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User and Service Guide Publication Number 54645-97012 December 1997 (pdf version Nov 1998) For Safety Information, Warranties, and Regulatory information, see the pages behind the Index.
The HP 54645A/D at a Glance Display shows current input signals • Eighteen (18) channels in main mode; 2 scope and 8 timing channels in delayed mode (HP 54645D) • Indicators for peak, avg, or normal acquisition, time base, channel activity, trigger and acquisition status • Softkey labels • Measurement results Storage Keys begin and end data acquisition • Run/Stop starts and stops continuous acquisitions • Single performs one acquisition • Autostore accumulates and displays the results of multiple acquisit
In This Book This manual will guide you in using and servicing the HP 54645A Oscilloscope and the HP 54645D Mixed-Signal Oscilloscope. This manual is organized in chapters as shown in the bleeder tab titles to the right.
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Contents 1 Getting Started Preparing the Oscilloscope 1–4 Check package contents 1–5 Adjust the handle 1–9 Connect the cables 1–9 Power-on the oscilloscope 1–10 Using the digital probes to probe a circuit Using the oscilloscope probes 1–13 Adjust display brightness 1–13 1–11 2 Front-Panel Overview Important Oscilloscope Considerations 2–2 HP 54645A/D Front Panels 2–6 Description of Front-Panel Areas 2–8 Front-Panel Operation 2–16 To use oscilloscope channels to view a signal 2–17 To use digital channels
Contents 3 Triggering HP 54645A/D Oscilloscopes Selecting Trigger Modes and Conditions 3–3 To select a trigger mode: Auto Lvl, Auto, Normal 3–3 To use holdoff 3–5 To trigger on a complex waveform 3–6 Triggering the HP 54645A Oscilloscope 3–7 To use external triggering 3–7 To trigger on an edge 3–8 To use glitch triggering 3–9 To use line triggering 3–10 To use TV triggering 3–10 Triggering the HP 54645D Mixed-Signal Oscilloscope 3–11 Trigger types 3–12 To define an edge trigger 3–16 To use line triggerin
Contents Run/Stop/Single/Autostore/Erase Operation 4–29 Acquiring Data 4–30 Memory Depth/Record Length 4–31 To run and stop an acquisition 4–33 To take a single trace 4–33 To capture a single event 4–34 To use Autostore 4–36 To Autostore Multiple Single Events 4–37 To erase the waveform display 4–38 Using Digital Channels to Probe Circuits 4–39 Saving and Recalling the Configuration 4–43 Using memories to save and recall configurations 4–43 To save, recall, and clear traces 4–46 To save or recall front-pa
Contents To use the XY display mode 5–14 To analyze video waveforms 5–18 Measuring Waveform Data 5–22 To make cursor measurements 5–22 To make frequency measurements automatically 5–26 To make time measurements automatically 5–28 To make voltage measurements automatically 5–32 6 Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To autoscale on a video signal 6–4 To trigger on a specific line of video 6–5 To trigger on all TV line sync pulses 6–7 To trigger on a specific field of the video signal 6–8
Contents Testing Threshold Accuracy 7–12 To set up and connect the equipment 7–13 To verify threshold accuracy 7–14 To check the output of the CALIBRATOR 7–15 To verify voltage measurement accuracy 7–16 To verify bandwidth 7–19 To verify horizontal ∆t and 1/∆t accuracy 7–22 To verify trigger sensitivity 7–24 To verify vertical output on Option 005 7–27 Adjusting the Oscilloscope 7–29 To adjust the power supply 7–30 To perform the self-calibration 7–33 To adjust the low-frequency compensation 7–35 To adjus
Contents To remove the power supply 8–8 To remove the keyboard 8–9 To remove the handle 8–9 Replacing the Option 005 board 8–10 Replaceable Parts 8–11 To order a replacement part 8–12 9 Performance Characteristics HP 54645A/D Oscilloscopes 9–3 HP 54645D Digital Channels 9–4 HP 54645A/D Oscilloscope Digitizing System 9–5 HP 54645D Logic Digitizing System 9–5 HP 54645A/D Time Base 9–6 HP 54645A/D Oscilloscope Trigger System 9–7 HP 54645A Oscilloscope Trigger System 9–8 HP 54645D Mixed-Signal Oscilloscope T
1 Getting Started
Getting Started When you use the HP 54645A/D Oscilloscopes to help test and troubleshoot your systems, you will do the following: • Prepare the oscilloscope by connecting it to power and setting up the handle and screen brightness as desired. • Define the measurement problem by understanding the parameters of the system you wish to test and the expected system behavior. • Set up channel inputs by connecting the probes to the appropriate signal and ground nodes in the circuit under test.
Getting Started The HP 54645A/D high-speed display can be used to isolate infrequently changing signals. You can then use the characteristics of these signals to help refine the trigger specification. See figure 1-2 below. For more information on triggering, data acquisition, data examination and measurement, and configuration, see chapters 3 and 4.
Preparing the Oscilloscope To prepare your HP 54645A Oscilloscope or HP 54645D Mixed-Signal Oscilloscope for use, you need to do the following tasks. After you have completed them, you will be ready to use the oscilloscope.
Getting Started Check package contents Check package contents • Verify that you received the following items and any optional accessories in the HP 54645A/D packaging. If anything is missing, contact your nearest Hewlett-Packard Sales Office. See figure 1-3. If the shipment was damaged, contact the carrier, then contact the nearest Hewlett-Packard Sales Office.
Getting Started Check package contents Figure 1-3 Items Supplied with the HP 54645A/D Oscilloscopes 1-6
Getting Started Check package contents Figure 1-4 Optional Accessories for the HP 54645A/D Oscilloscopes 1-7
Getting Started Check package contents Table 1-1 Power Cords Plug Type Cable Part No. Plug Description Length in/cm Color Opt 903 (U.S.A.) 124V ** 8120-1378 Straight (NEMA5-15P*) 90/228 Jade Gray Opt 900 (U.K.
Getting Started Adjust the handle Adjust the handle 1 Grasp the handle pivot points on each side of the instrument and pull the pivot out until it stops. 2 Without releasing the pivots, swivel the handle to the desired position. Then release the pivots. Connect the cables 1 Check to ensure that you received everything that is supplied with the oscilloscope. 2 Connect the oscilloscope to power and turn it on.
Getting Started Power-on the oscilloscope Power-on the oscilloscope 1 Connect the power cord to the rear of the HP 54645A/D, then to a suitable ac voltage source. The HP 54645A/D power supply automatically adjusts for input line voltages in the range 100 to 240 VAC. Therefore, you do not need to adjust the input line voltage setting. The line cord provided is matched by HP to the country of origin. Ensure that you have the correct line cord. See table 1-1. 2 Press the power switch.
Getting Started Using the digital probes to probe a circuit Using the digital probes to probe a circuit 1 If you feel it’s necessary, turn off the power supply to the circuit under test. Turning off power to the circuit under test would only prevent damage that might occur if you accidentally short two lines together while connecting probes. You can leave the HP 54645A/D powered on because no voltage appears at the probes. 2 Connect the digital probe cable to HP 54645D.
Getting Started Using the digital probes to probe a circuit 6 Connect the ground lead on each set of channels, using a probe grabber. The ground lead improves signal fidelity to the instrument, ensuring accurate measurements. 7 Repeat steps 3 through 6 until you have connected all points of interest. 8 If you need to remove a probe lead from the cable, insert a paper clip or other small pointed object into the side of the cable assembly, and push to release the latch while pulling out the probe lead.
Getting Started Using the oscilloscope probes Using the oscilloscope probes 1 Connect the HP 10074A 1.5-meter, 10:1 oscilloscope probe BNC connector to the channel 1 or 2 input on the HP 54645A or to channel A1 or A2 on the HP 54645D. 2 Connect the probe grabber to the circuit point of interest. Be sure to connect the ground lead to a ground point. Adjust display brightness The brightness control is at the lower left corner of the display.
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2 Front-Panel Overview
Front-Panel Overview Before you make measurements using the HP 54645A Oscilloscope and HP 54645D Mixed-Signal Oscilloscope, you must first set up the instrument using front-panel controls. Then, make the measurement and read the display results. See the following pages for descriptions of controls. The HP 54645A/D operates much like an analog scope, but it can do much more. Spending a few minutes to learn some of this capability will take you a long way toward more productive troubleshooting.
Front-Panel Overview Important Oscilloscope Considerations Viewing Signal Detail with Display Mode Remember how you had to constantly adjust the brightness on old analog scopes to see a desired level of detail in a signal, or to see the signal at all? With the HP 54645A/D, this is not necessary. The HP 54645A/D brightness knob operates much like the brightness knob on your computer screen, so you should set it to a level that makes for comfortable viewing, given the room lighting, and leave it there.
Front-Panel Overview Important Oscilloscope Considerations The simplest averaging is “smoothing.” For example, the sample rate at a Time/Div setting of ≥ 2 µs/div allows the extra 5-ns samples to be smoothed together, smoothing the data into one sample, which is then displayed. As with Peak Detect, smoothing has no effect at less than 2 µs/div. Smoothing works on a single acquisition (even untriggered and single-shot).
Front-Panel Overview Important Oscilloscope Considerations Delayed Sweep Delayed sweep on the HP 54645A/D is a simultaneous display of the waveform at two different sweep speeds. Because of the deep memory in the MegaZoom technology, it is possible to capture the main display at 1 ms/div, and redisplay the same trigger in the delayed display at any desired faster time base. There is no limit imposed on the zoom ratio between the main and delayed displays.
Front-Panel Overview HP 54645A/D Front Panels HP 54645A/D Front Panels Figure 2-1 Measurement Keys Display Storage Keys Trigger Keys Softkeys Brightness Control Calibration Output HP 54645A Oscilloscope Front Panel 2-6 Power Channel Inputs/ Controls Horizontal Controls Trigger Input
Front-Panel Overview HP 54645A/D Front Panels Figure 2-2 Measurement Keys Display Storage Keys Trigger Keys Softkeys Brightness Control Calibration Output Power Analog Channel Inputs/Controls Horizontal Digital Channel Controls Inputs/Controls HP 54645D Mixed-Signal Oscilloscope Front Panel 2-7
Front-Panel Overview Description of Front-Panel Areas Description of Front-Panel Areas Table 2-1 HP 54645A Front-Panel Areas Front-Panel Areas Functions Display Shows waveforms, measurement results and instrument configuration settings. Softkeys Set up various options for each major function, varying dynamically depending on the required function.
Front-Panel Overview Description of Front-Panel Areas Table 2-2 HP 54645D Front-Panel Areas Front-Panel Areas Functions Control Knobs Display Shows waveforms, measurement results and instrument configuration settings. Softkeys Set up various options for each major function, varying dynamically depending on the required function. General Controls Include various measurement functions, configuration, screen, and measurement results, save/recall, printing, and Autoscale functions.
Front-Panel Overview Description of Front-Panel Areas Table 2-3 HP 54645A/D Front-Panel Specifics General Front-Panel Areas Description Applies to Unit: Waveform Display The waveform display area shows all acquisition results. You can change the graticule or turn it off entirely using the Display menu. HP 54645A/D Softkeys Softkeys are shown along the bottom of the display. Some softkeys have an immediate action, such as taking you to another menu or initiating a measurement.
Front-Panel Overview Description of Front-Panel Areas General Front-Panel Areas Description Keypad and Softkeys Some keys, such as On/Off and Label also have special functions while in the menus that they activate. Keys on the HP 54645A/D front panels include the following: Control Knobs Applies to Unit: White keys have an immediate action, such as starting or stopping the instrument. No menus are associated with white keys.
Front-Panel Overview Description of Front-Panel Areas General Front-Panel Areas Display Regions Description Applies to Unit: The Position knob moves the selected channel to a new vertical position on the display. The HP 54645D has an additional Position knob for the DIGITAL channels. HP 54645A/D The Entry knob selects from multiple choices in menus. It also occasionally duplicates the function of the Select knob.
Front-Panel Overview Description of Front-Panel Areas Front-Panel Areas Description Status Indicators Status indicators include the following: Applies to Unit: Channels that are turned off are visible only if you select a channel that is off by using the Select knob. HP 54645D Average mode is indicated by “Av”. Peak detect mode is indicated by “Pk”. These indicators are active when displayed in inverse video on the line above the display.
Front-Panel Overview Description of Front-Panel Areas Front-Panel Areas Description Applies to Unit: Trigger condition shows the current trigger mode. The Auto Level and Auto trigger modes display the "Auto" indicator. For Edge trigger mode, it also shows the trigger condition and channel number. HP 54645A/D In normal trigger mode, when the TV trigger mode is selected, "TV" is displayed; when in Auto level or Auto modes, "TV" is replaced by the "Auto" indicator.
Front-Panel Overview Description of Front-Panel Areas Front-Panel Areas Description Applies to Unit: Channel Numbers The channel numbers are always shown along the left edge of the display. HP 54645A/D Channel Labels You can assign channel labels to help you remember the function of each channel in your circuit, or disable the labels to increase the waveform display area.
Front-Panel Operation By now you should be somewhat familiar with the VERTICAL or ANALOG, STORAGE, HORIZONTAL, TRIGGER, and DIGITAL groups of front-panel keys and knobs. You should also know how to determine the setup of the oscilloscope by looking at the status line. If you are unfamiliar with this information, we recommend that you read the introductory material at the start of this manual.
Front-Panel Overview To use oscilloscope channels to view a signal To use oscilloscope channels to view a signal • To configure the instrument quickly, press Autoscale . • To undo the effects of autoscale, press Setup , then press Undo Autoscale. • To set the instrument to the factory-default measurement configuration, press Setup , then press Default Setup.
Front-Panel Overview To use digital channels to view a signal To use digital channels to view a signal • To configure the instrument quickly, press Autoscale . • To undo the effects of autoscale, press Setup , then press Undo Autoscale. • To set the instrument to the factory-default measurement configuration, press Setup , then press Default Setup. Example Install grabbers on channels D0 and D1.
Front-Panel Overview To display signals automatically using Autoscale To display signals automatically using Autoscale • To configure the instrument quickly, press Autoscale . Autoscale displays all connected signals that have activity. • To undo the effects of autoscale, press Setup , then press Undo Autoscale.
Front-Panel Overview To apply the default factory configuration During Autoscale, the delay is set to 0.0 seconds, the Time/Div setting is a function of the input signal (about 2 periods of the triggered signal on the screen), and the triggering mode is set to edge. The instrument stays in Normal or Peak Detect display mode, depending on what was selected when Autoscale was performed. Vectors remain in the state they were before the Autoscale.
Front-Panel Overview To adjust oscilloscope vertical scaling To adjust oscilloscope vertical scaling This exercise guides you through the vertical keys, knobs, and status line. 1 Center the signal on the display using the Position knob. The Position knob moves the signal vertically; the signal is calibrated. Notice that as you turn the Position knob, a voltage value is displayed for a short time, indicating how far the ground reference is located from the center of the screen.
Front-Panel Overview To adjust oscilloscope vertical scaling • Toggle each softkey and notice which keys cause the status line to change. Channels 1 and 2 have a vernier softkey that allows the Volts/Div knob to change the vertical step size in smaller increments. These smaller increments are calibrated, which result in accurate measurements, even with the vernier turned on. • To turn the channel off, either press (for HP 54645A) or (for HP 54645D) a second time or press the left-most softkey.
Front-Panel Overview To adjust oscilloscope vertical scaling To Expand the Vertical Signal When changing the Volts/Div for analog channels, you can have the signal expand (or compress) about the signal offset or the ground point. This works well with two signals displayed, because you can position and see them both on the screen while you change the amplitude. • To expand the signal about the offset, press Print/Utility . Then select System Config and Expand Vertical Center.
Front-Panel Overview To turn analog channels on and off To turn analog channels on and off • To turn off analog channel #1, press 1 (on the HP 54645A), or A1 (on the HP 54645D), then press the leftmost softkey until Off is highlighted. • To turn off analog channel #2, press 2 (on the HP 54645A), or A2 (on the HP 54645D), then press the leftmost softkey until Off is highlighted.
Front-Panel Overview To turn digital channels on and off (HP 54645D) To turn digital channels on and off (HP 54645D) • To turn digital channels 0 through 7 on, press D0-D15 , then press the D0 - D7 On softkey. To turn these channels off, press the Off softkey. • To turn digital channels 8 through 15 on, press D0-D15 , then press the D8 - D15 On softkey. To turn these channels off, press the Off softkey. • To turn on an individual channel, press D0-D15 .
Front-Panel Overview To rearrange the digital channels (HP 54645D) To rearrange the digital channels (HP 54645D) 1 Turn the Select knob to choose the digital channel you want to move. Only channels that are currently on may be moved. 2 Turn the Position knob to move the selected channel to a new position. Turning the Position knob counter-clockwise moves the channel down; turning the knob clockwise moves the channel up.
Front-Panel Overview To operate the time base controls To operate the time base controls The following exercise guides you through the time base keys, knobs, and status line. • Turn the Time/Div knob and notice the change it makes to the status line. The Time/Div knob changes the sweep speed from 2 ns to 50 s (HP 54645A) and from 5 ns to 50 s (HP 54645D) in a 1-2-5 step sequence, and the value is displayed in the status line.
Front-Panel Overview To start and stop an acquisition All events displayed left of the trigger point ▼ happened before the trigger occurred, and these events are called pre-trigger information. You will find this feature very useful because you can now see the events that led up to the trigger point. Everything to the right of the trigger point ▼ is called post-trigger information. The amount of delay range (pre-trigger and post-trigger information) available depends on the sweep speed selected.
Front-Panel Overview To use the Entry and Select knobs To use the Entry and Select knobs The Select knob (HP 54645D only) always changes the selected channel. In most menus, its order is screen-oriented. In the simple pattern and advanced pattern definition menus, it moves from the lowest to highest number on clockwise rotation. The Entry knob increments and decrements the selected field—for example, glitch time and setup memory number. It also moves the selected cursor when cursors are on.
Front-Panel Overview To make cursor measurements To make cursor measurements The following steps guide you through the front-panel Cursors key. You can use the cursors to make custom voltage or time measurements on scope signals, and timing measurements on digital channels. 1 Connect a signal to the oscilloscope and obtain a stable display. 2 Press Cursors .
Front-Panel Overview To make cursor measurements On HP 54645D, the Readout softkey gives a reading of the time or voltage cursor measurement. • For the time cursor readout, you can select Time, Hex, Binary, or Degrees. Binary displays all digital channels by channel number. Hex shows only the displayed channels, with the top channel displayed as the most significant bit.
Front-Panel Overview To use delayed sweep To use delayed sweep Delayed sweep is a magnified portion of the main sweep. You can use delayed sweep to locate and horizontally expand part of the main sweep for a more detailed (high-resolution) analysis of signals. The following steps show you how to use delayed sweep. Notice that the steps are very similar to operating the delayed sweep in analog oscilloscopes. 1 Connect a signal to the oscilloscope and obtain a stable display. 2 Press Main/Delayed .
Front-Panel Overview To modify the graticule To modify the graticule 1 Press Display . 2 Press one of the Grid softkeys to define the graticule used for the waveform area on the display. • Frame has a set of hash marks along the top and bottom of the display only. Major divisions are indicated by longer hash marks. • Full has a set of hash marks through the center of the waveform display area, with major divisions indicated by a full-height dotted line through the waveform display.
Front-Panel Overview To print the display To print the display You can print the waveform display and status line to an HP printer or Epson-compatible printer attached to one of these optional interface modules: HP 54650A HP-IB Interface Module HP 54652A Parallel Interface Module HP 54652B RS-232/Parallel Interface Module HP 54657A Measurement/Storage Module (HP-IB) HP 54659B Measurement/Storage Module (RS-232/Parallel) 1 If you have one of these modules installed, configure the module first.
3 Triggering HP 54645A/D Oscilloscopes
Triggering HP 54645A/D Oscilloscopes The HP 54645A/D Oscilloscopes provide a full set of features to help automate your measurement tasks, including MegaZoom technology to help you capture and examine the stored waveforms of interest, even untriggered waveforms. With these oscilloscopes you can: • Modify the way the oscilloscope acquires data. • Set up simple or complex trigger conditions, as needed, to capture only the sequence of events you want to examine.
Selecting Trigger Modes and Conditions The trigger mode affects the way in which the oscilloscope searches for the trigger. Figure 3-1 shows the conceptual representation of acquisition memory. Think of the trigger event as dividing acquisition memory into a pre-trigger and post-trigger buffer. The position of the trigger event in acquisition memory is defined by the time reference point and the delay setting.
Triggering HP 54645A/D Oscilloscopes To select a trigger mode: Auto Lvl, Auto, Normal When you select Single, the oscilloscope will fill acquisition memory, and continue flowing data through the pre-trigger buffer until the auto trigger overrides the searching and commands a trigger. At the end of the trace, the scope will stop and display the results. Normal mode Use Normal trigger mode for low repetitive-rate signals.
Triggering HP 54645A/D Oscilloscopes To use holdoff To use holdoff By setting the Holdoff, you can synchronize triggers. The oscilloscope will trigger on one edge of the waveform, and ignore further edges until the holdoff time expires. The oscilloscope will then re-arm the trigger circuit to search for the next edge trigger. This allows the oscilloscope to trigger on a repeating pattern in a waveform. • Turn the holdoff knob in the trigger section to increase and decrease trigger holdoff time.
Triggering HP 54645A/D Oscilloscopes To trigger on a complex waveform To trigger on a complex waveform The difficulty in viewing a complex waveform is triggering on the signal. The simplest trigger method is to trigger the oscilloscope on a sync pulse that is associated with the waveform. If there is no sync pulse, use these steps to trigger on a periodic complex waveform. 1 Connect a signal to the oscilloscope. 2 Set the trigger level to the middle of the waveform.
Triggering the HP 54645A Oscilloscope The HP 54645A Oscilloscope allows you to synchronize the display to the actions of the circuit under test by defining a trigger condition. The triggering modes include Auto Lvl, Auto, and Normal. Triggering types include Glitch, TV, and Slope/Edge and you can use channels 1 or 2, Line, or the External Trigger BNC for the source.
Triggering HP 54645A/D Oscilloscopes To trigger on an edge To trigger on an edge 1 Press Source . 2 Select 1, 2, Ext, or Line as the trigger source. You can choose a channel that is turned off as the source for the edge trigger. You cannot select the Line trigger source when Glitch trigger mode is selected. 3 Press Slope/Glitch to set the trigger condition. 4 Select either the rising edge or falling edge softkey to choose whether the trigger will occur on the rising or falling edge of the input signal.
Triggering HP 54645A/D Oscilloscopes To use glitch triggering To use glitch triggering 1 Press Slope/Glitch . Then select Glitch. 2 Select Glitch Menu. 3 Define the polarity, duration qualifier, and duration time for the glitch.
Triggering HP 54645A/D Oscilloscopes To use line triggering To use line triggering • Press Source . Then select Line. To use TV triggering 1 Press Source . Select 1 or 2 for the Trigger Source channel. 2 Press Slope/Glitch . Then select TV. 3 Select TV Menu. 4 Select positive or negative polarity. 5 Select the TV mode. • Pressing Field 1 triggers on the video signal field 1 portion (odd fields). • Pressing Field 2 triggers on the video signal field 2 portion (even fields).
Triggering the HP 54645D Mixed-Signal Oscilloscope The HP 54645D Mixed-Signal Oscilloscope allows you to synchronize the oscilloscope display to the actions of the circuit under test by defining a trigger condition. The trigger types include edge, pattern, and advanced, allowing you to match the complexity of the trigger to that of the data you want to capture. The triggering modes include Auto Lvl, Auto, and Normal. Advanced triggering consists of Glitch, Advanced Pattern, and TV.
Triggering HP 54645A/D Oscilloscopes Trigger types Trigger types These trigger types are available: • Edge trigger • Pattern trigger • Advanced trigger Changes to the trigger specification are applied when you make them. If the oscilloscope is stopped when you change a trigger specification, the scope will use the new specification when you press Run/Stop, Single, or Autostore.
Triggering HP 54645A/D Oscilloscopes Trigger types Glitch Trigger The advanced glitch trigger menu lets you select the analog (A1 or A2) or digital (D0-D15) channel on which to capture a glitch event. You specify the polarity and duration qualifier—either less than (<), greater than (>), or a range—for the glitch. The HP 54645D can capture glitches >8 nanoseconds and <100 seconds.
Triggering HP 54645A/D Oscilloscopes Trigger types Specifying a Logic Threshold You can specify a threshold for the logic channels. See “To change the logic threshold for input signals” in chapter 4 for information about setting a threshold on the HP 54645D. Advanced Pattern Trigger In advanced pattern trigger, you define a maximum of two pattern and edge sources that are combined with a variety of operators to form the complete trigger specification.
Triggering HP 54645A/D Oscilloscopes Trigger types Sharing of Sources The source definitions for the simple pattern trigger are shared with the Pattern 1 and Edge 1 sources of the advanced pattern trigger specification. Thus, changes to the simple pattern trigger will affect that specification, and changes to Pattern 1 and Edge 1 in the advanced pattern trigger specification will affect the simple pattern trigger. Logical Combinations In advanced trigger, settings within pattern terms are logically ANDed.
Triggering HP 54645A/D Oscilloscopes To define an edge trigger To define an edge trigger 1 Press Edge . 2 Select a channel as the trigger source using either the Select knob or by pressing a Trigger Source softkey. You can choose a channel that is turned off as the source for the edge trigger. 3 Press one of the Edge softkeys to choose whether the trigger will occur on the rising or falling edge.
Triggering HP 54645A/D Oscilloscopes To define a pattern trigger To define a pattern trigger 1 Press Pattern . 2 For each analog channel (A1 or A2) or digital channel (D0-D15) you want to include in the desired pattern, press the Source softkey to select the channel, or rotate the Entry knob or the Select knob.
Triggering HP 54645A/D Oscilloscopes To use glitch triggering To use glitch triggering 1 Press Advancd . Then select Glitch. 2 Select Glitch Menu. 3 Select the analog channel (A1 or A2) or digital channel (D0-D15) source for the trigger by pressing the Source softkey until the desired source is highlighted. 4 Select positive or negative polarity for the glitch to capture.
Triggering HP 54645A/D Oscilloscopes To define an advanced pattern trigger To define an advanced pattern trigger The advanced triggering operation depends on previous selections in the Advanced Trigger menu. 1 Press Advancd . Then select Pattern. 2 Press the Overview softkey to turn on the trigger overview, if desired. The trigger overview display shows all the choices available in this menu. 3 Select Pattern Menu.
Triggering HP 54645A/D Oscilloscopes To define an advanced pattern trigger 5 Select the source(s) for the trigger operator by pressing the leftmost Source softkey until the desired source is highlighted. Refer to the table of trigger operators and sources to see the sources and operators with which they can be used.
Triggering HP 54645A/D Oscilloscopes To define an advanced pattern trigger 9 To set up a pattern trigger source, do the following: a Select a channel for the source. • To set the condition for that channel, press the L, H, or X softkey. • To clear the conditions for all channels, press Clear Pattern. b Repeat step a for all channel sources you want to define. c Press Previous Menu to return to the Advanced Pattern Trigger menu.
Triggering HP 54645A/D Oscilloscopes To define an advanced pattern trigger Setup rules Remembering the following rules will make it easier to work with the advanced triggering capabilities: • Duration operators are valid when only pattern terms are involved. Duration is not selectable when any edge term is selected as a source. • When you have selected a combination source, like Pattern 1 AND Edge 1, you cannot directly define the pattern or edge.
Triggering HP 54645A/D Oscilloscopes To define an advanced pattern trigger Example Suppose you have a pulse train where one of the pulses is of constant duration (4 µs) and all other signals of interest are repeated with that pulse train, as shown in the following figure.
Triggering HP 54645A/D Oscilloscopes To define an advanced pattern trigger Source Operator and Parameters Pattern/Edge Pattern 1 Then L on channels D2, D1, and D0, others don’t care Pattern 2 L on channels 2 and 1, H on channel 0, others don’t care All Qualifiers must be Satisfied to Trigger the Oscilloscope When setting up an advanced trigger, remember that all required events must be satisfied to trigger the oscilloscope.
4 MegaZoom Concepts and Oscilloscope Operation
MegaZoom Concepts and Oscilloscope Operation This chapter gives an overview of some oscilloscope concepts that will help you make better measurements. It discusses the relationship between the time base setting and other time-dependent oscilloscope functions, explains how to achieve the most accurate signal fidelity through good probing practices, and describes how glitch detection works.
MegaZoom Concepts MegaZoom technology combines the advantages of conventional deep-memory digital oscilloscopes with the responsiveness and update rate of traditional analog oscilloscopes. Conventional deep-memory digital oscilloscopes are known for their ability to capture long time intervals while still maintaining high sample rates.
MegaZoom Concepts Deep Memory Deep Memory The primary advantage of a deep-memory oscilloscope is sustained sample rate, allowing you to capture at the maximum sample rate and capture a much longer time window. For example, you may want to capture a fast digital event, such as an interrupt line being asserted, while being able to look far out in time to see when the line was de-asserted.
MegaZoom Concepts Oscilloscope Responsiveness Oscilloscope Responsiveness An important element of an oscilloscope is how responsive it is to control changes. After a control is changed, such as the time/division, if you must wait for the test instrument to respond, the feedback loop between the instrument and you can become difficult. You could confuse adjustments because of the delay between making a change to the instrument and seeing the effect of that change take place.
MegaZoom Concepts Display Update Rate Display Update Rate In analog oscilloscopes, the scope is “blind” while the electron beam is reset to the left side of the screen. Thus, the update rate of an analog scope seems high because the blind or dead time of the analog scope is low. High update rate is advantageous because infrequent or random events that happen while the scope is blind are missed, and thus not displayed.
MegaZoom Concepts Display Modes Display Modes Remember how when using your analog oscilloscope you had to constantly adjust the brightness? You did this to see the desired level of detail in a signal, or sometimes to see the signal at all! The brightness knob on the HP 54645A/D operates much like the brightness knob on your computer screen. You should set it to a level that makes for comfortable viewing, given the room lighting, and keep it there.
MegaZoom Concepts Display Modes Normal Mode Normal mode is the display mode that you will use most of the time. For the majority of use models and signals, normal mode yields the best scope picture of the waveform. In the case of the HP 54645A/D, the analog channels can have up to 1 million samples behind the 4,000-point scope display. Some compression of samples to display points is obviously necessary. Normal mode follows the model of the dithered system described earlier.
MegaZoom Concepts Display Modes Figure 4-1 Attempting to Capture Narrow Pulse As you change the Time/Div setting (zoom in), and look at a smaller time window around the trigger, the percentage of the acquired samples to the displayed samples increases. For example, at 2 µs/div (20 µs/div across the screen), we now display every sample acquired in that time window (20 µs / 5 ns = 4,000 samples). By zooming in to this range, we can see the pulse of interest.
MegaZoom Concepts Display Modes Between the 500-µs/div picture (figure 4-1), and the 2-µs/div picture (figure 4-2), whether or not the pulse or some part of the pulse is displayed is simply a statistical problem. For every new sweep speed, a new ratio of displayed-versus-sample points is necessary to provide the “best” representative picture. Thus, you may see part of the pulse at one sweep speed, and it may disappear at the next sweep speed.
MegaZoom Concepts Display Modes Peak Detection Prevents Aliasing Aliasing produces misleading information. The peak detection circuitry in the HP 54645A/D helps to prevent aliasing by identifying additional transitions that occur between logic samples. Because of the high sample rate of the HP 54645A/D MegaZoom technology, you should not see aliasing. Consider the following example. The following picture shows a simple square wave with the scope in peak detect mode at 1 µs/div.
MegaZoom Concepts Display Modes Now consider the same waveform at 200 µs/div. All that remains is the signal’s maximum and minimum values. This could lead you to believe the signal transitioned very infrequently because of the lack of any intermediate signal values. Figure 4-4 Same Square Wave in Peak Detect Mode at 200 µs/div on HP 54600 The HP 54645A/D goes one step further in peak detect mode. In addition to the maximum and minimum values, the HP 54645A/D includes some “normal” or dithered samples.
MegaZoom Concepts Display Modes Figure 4-5 Same Square Wave on HP 54645D The maximum and minimum values are displayed in additional to some normal samples. The additional normal samples here give you a better understanding of the actual waveform by showing you the signal transitions in addition to the maximum and minimum values. Changing Display Modes While Stopped One of the benefits of the HP 54645A/D is that you can change display modes after you acquire data.
MegaZoom Concepts Display Modes Peak Detect versus Normal on HP 54645D Digital Channels In a digital system design, a glitch is an unintentional or unexpected signal transition which may or may not pass through the logic threshold. The HP 54645D supports capturing glitches on digital channels during data acquisition. However, because the scope cannot determine whether the transition was valid, it defines the concept of a glitch differently.
MegaZoom Concepts Display Modes Average Mode Averaging is a way to pull the signal out of the noise. Averaging works better than either a bandwidth limit or a brightness control. The averages you can select include "Smoothing", 4, 8, 16, 32, 64, 128, and 256. Smoothing is an oversampling technique, and operates as described in the “Display Modes” section in this chapter.
MegaZoom Concepts Display Modes Vectors On/Off One of the most fundamental choices you must make about your display is whether to draw vectors between the samples, or simply let the samples fill in the waveform. To some degree, this is a matter of personal preference, but it also depends on the waveform. • Having vectors on slows the display of the oscilloscope. This works better for slower sweep speeds, peak detect or average displays, and signals with stable triggers.
MegaZoom Concepts Display Modes Displaying Analog Channels After the Acquisition The two scope channels are always acquired, so you can turn them on and look at them even if they were off during the acquisition. You can do math functions on channels that are turned off, but you cannot make measurements on them.
MegaZoom Concepts Pan and Zoom Pan and Zoom The ability to pan (move horizontally) and zoom (expand or compress horizontally) an acquired waveform is important because of the additional insight it can reveal about the captured waveform. This additional insight is often gained from seeing the waveform at different levels of abstraction. You may want to view both the big picture and the specific little picture details.
MegaZoom Concepts Pan and Zoom In peak detect display mode, the useful limit is more apparent from the display. As we zoom in on peak detected data, we eventually see the resolution of the peak detected information. The appearance of the resolution limit differs based on whether vectors are on or off. With vectors on, the resolution limit in peak detect appears as shown in the following figure.
MegaZoom Concepts Pan and Zoom With vectors off, the resolution limit appears as shown in the following figure. Figure 4-8 max value min value Horizontal lines indicate the search time (line length) and max and min values (line position). max value min value Normal point Resolution Limit in Peak Detect with Vectors Off Recall that in peak detect, the HP 54645A/D shows both peak detect information and some “normal” points.
MegaZoom Concepts Recovering the waveform on the screen Recovering the waveform on the screen In the HP 54645A/D, pressing Run/Stop freezes the screen. When either of the following occur, there will be several triggers of information on the screen. • The scope is running at fast sweep speeds (1 µs/div and faster). For example, at 5 ns/div, the scope acquires 10 samples per trigger, and the display record will contain many different triggers.
MegaZoom Concepts Changing the time reference position Changing the time reference position 1 Press Main/Delayed . 2 Choose the time reference position from the Time Reference softkeys: • To set the time reference so that most of the acquired data follows the trigger, press Left. The time reference indicator will be one division in from the left side of the display. The trigger event will be at the same location unless the delay is set to a value other than 0.
MegaZoom Concepts Changing the time reference position The time reference position sets the initial position of the trigger event within acquisition memory and on the display, with delay set to 0. The delay setting sets the specific location of the trigger event with respect to the time reference position. The time reference setting affects the delayed sweep as described in the following ways. When the horizontal mode is set to Main, the delay positions the main sweep relative to the trigger.
MegaZoom Concepts Changing the time reference position At 5 µs/div, we are sampling at 200 MSa/s (scope), and 400 MSa/s (digital). When no delay value is set, and the time reference is set to Center, the trigger point is displayed at the center of the screen. Consider a measurement where we want to view a signal from 30 µs before the trigger point, and 30 µs after the trigger point.
MegaZoom Concepts Changing the time reference position When we pan the display (move it horizontally) back and set the delay to 15 µs, the trigger point is displayed on the screen. The part of the signal we see displayed at the center of the screen is to the right of the trigger point. The result resembles: Figure 4-10 The trigger event is displayed on the screen. Center screen still shows part of the signal to the right of the trigger.
MegaZoom Concepts Changing the time reference position Setting a negative delay lets us look at the part of the signal to the left of the trigger point. Suppose we set the time reference to Right, with a sweep speed of 5 µs, and a delay value of -30 µs. When we perform a single acquisition, the display resembles: Figure 4-11 The trigger event is off the screen to the right. Center screen shows part of the signal to the left of the trigger.
MegaZoom Concepts Changing the time reference position If we set the time reference to center, then pan the display back to set the delay to 0 µs, the trigger point is displayed at center screen, and the result resembles: Figure 4-12 Panning the Display to View the Trigger Point Here, the trigger point is in memory. For more information on the specific limits available under delayed sweep, see the chapter “Performance Characteristics.
MegaZoom Concepts Changing the time reference position Post Acquisition Processing In addition to changing display parameters after the acquisition, all of the measurements and math functions can be done after the acquisition. The measurement and math functions will be re-calculated as you pan/zoom and turn on/off channels. As you zoom in and out on the signal, you affect the resolution of the display, and the resolution of functions and measurements.
Run/Stop/Single/Autostore/Erase Operation During an acquisition, the oscilloscope examines the input voltage at each input probe. • For analog channels on HP 54645A/D, the input voltage is determined by the Volts/Div settings. • For digital channels in the HP 54645D, at each sample, the scope compares the input voltage to the logic threshold. If the voltage is above the threshold, the oscilloscope stores a “1” in sample memory; otherwise, it stores a “0.
Run/Stop/Single/Autostore/Erase Operation Acquiring Data Acquiring Data The HP 54645A/D operates like an analog scope, but it can do much more. Spending a few minutes to learn some of this capability will take you a long way toward more productive troubleshooting. Single versus Run/Stop The HP 54645A/D both have a Single key and a Run/Stop key. When you press Run/Stop, the trigger processing rate is optimized over memory depth. Single always uses the maximum memory available.
Run/Stop/Single/Autostore/Erase Operation Memory Depth/Record Length Memory Depth/Record Length Run/Stop versus Single The HP 54645A/D both have a Single key and a Run/Stop key. When you press Run, the trigger processing or update rate is optimized over memory depth. When you press Single, memory depth is maximized. Single For a single acquisition, all available memory is filled with each acquisition, regardless of sweep speed. To acquire data with the longest possible record length, use Single.
Run/Stop/Single/Autostore/Erase Operation Memory Depth/Record Length Given that this is the case, we now have two options: • We could acquire a full 500,000 points for every acquisition, resulting in some samples being “off screen.” • We could decrease the acquired record size, only filling a fraction of the available 500,000 points. When continuously running, the scope will automatically decrease the record sizes at the faster time base settings to further increase screen update rate.
Run/Stop/Single/Autostore/Erase Operation To run and stop an acquisition To run and stop an acquisition • To begin an acquisition, press the Run/Stop key. The instrument begins acquiring data while searching for a trigger condition. The RUN indicator is shown in the upper-right corner of the display. If a trigger occurs, the acquired data is shown in the display. • To stop an acquisition in process, press the Run/Stop key.
Run/Stop/Single/Autostore/Erase Operation To capture a single event To capture a single event To capture a single event, you need some previous knowledge of the signal to set up the trigger level and slope. For example, if the event is derived from TTL logic, a trigger level of 2 volts should work on a rising edge. These steps show you how to use the oscilloscope to capture a single event. 1 Connect a signal to the oscilloscope. 2 For HP 54645A, set up the trigger. a Press Source . Select a trigger source.
Run/Stop/Single/Autostore/Erase Operation To capture a single event 4 Press Single . Pressing Single arms the trigger circuit. When the trigger conditions are met, data appears on the display, representing the data points that the oscilloscope obtained with one acquisition. Pressing the Single again re-arms the trigger circuit and erases the display. Operating Hints When Trigger Mode is set to Auto or Auto Lvl (auto-single mode), each time Single is pressed the oscilloscope will wait for a valid trigger.
Run/Stop/Single/Autostore/Erase Operation To use Autostore To use Autostore With Autostore or infinite persistence, the scope updates the display with new acquisitions, but does not erase the results of previous acquisitions. Rather than being erased by subsequent acquisitions, each pixel memory location turned on by a previous acquisition is turned into a pixel in half-bright. Thus, the results of all previous acquisitions are displayed in half-bright, with the latest acquisition in full-bright.
Run/Stop/Single/Autostore/Erase Operation To Autostore Multiple Single Events To Autostore Multiple Single Events To Autostore single events, you first need to configure the instrument to do single Autostores. 1 Press Autostore to put the instrument in Autostore mode. This causes the instrument to run. 2 Press Single to take a single autostored acquisition. After the single acquisition, the scope will stop. 3 You may want to press Erase to display a clean screen.
Run/Stop/Single/Autostore/Erase Operation To erase the waveform display To erase the waveform display • Press Erase . Acquisition memory and the current display are immediately erased. If the instrument is in Run or Autostore mode, however, and the oscilloscope finds a trigger condition, the display will be quickly updated after the erasure. Summary of Oscilloscope Storage Keys Run—acquires data and displays the most recent trace. Stop—freezes the display. Single—acquires a single trace.
Run/Stop/Single/Autostore/Erase Operation Using Digital Channels to Probe Circuits Using Digital Channels to Probe Circuits You may encounter problems when using the HP 54645D that are related to probing. These problems fall into two categories: probe loading and probe grounding. Probe loading problems generally affect the circuit under test, while probe grounding problems affect the accuracy of the data to the measurement instrument.
Run/Stop/Single/Autostore/Erase Operation Using Digital Channels to Probe Circuits Ω Figure 4-14 Ω Ω High-Frequency Probe Equivalent Circuit The impedance plots for the two models are shown in these figures. By comparing the two plots, you can see that both the series tip resistor and the cable’s characteristic impedance extend the input impedance significantly. The stray tip capacitance, which is generally small (1 pF), sets the final break point on the impedance chart.
Run/Stop/Single/Autostore/Erase Operation Using Digital Channels to Probe Circuits Probe Grounding A probe ground is the low-impedance path for current to return to the source from the probe. Increased length in this path will, at high frequencies, create large common mode voltages at the probe input.
Run/Stop/Single/Autostore/Erase Operation Using Digital Channels to Probe Circuits In addition to the common mode voltage—ground bounce—longer ground returns also degrade the pulse fidelity of the probe system. Risetime is increased, and ringing, due to the undamped LC circuit at the input of the probe, is also increased. Because the HP 54645D digital channels display reconstructed waveforms, they do not show ringing and perturbations.
Saving and Recalling the Configuration With the HP 54645A/D Oscilloscopes, you can save traces and the oscilloscope setup. Traces are stored in trace memories, and front-panel setups are stored in setup memories. Using memories to save and recall configurations Trace memory Two trace memories, also called pixel memories, are available in the HP 54645A/D. These allow you to save the visible portion of the acquisition—the displayed waveform—for later recall and comparison with other measurements.
Saving and Recalling the Configuration Using memories to save and recall configurations Figure 4-17 Selects trace memory Selects whether the memory is on (displayed) or off Saves current waveform to the selected memory Erases the selected memory Sets the HP 54645A/D to the configuration saved with the waveform Trace Memory Softkeys on HP 54645D with HP 54659B Measurement/Storage Module Installed Setup memory The HP 54645A/D has 10 separate setup memories that allow you to save the current configurat
Saving and Recalling the Configuration Using memories to save and recall configurations For example, suppose that you use the HP 54645A/D in field testing of a system where ten separate tests are used. You can predefine the test configurations and save them in setup memories 1-10. You might also record the expected results as part of field test documentation.
Saving and Recalling the Configuration To save, recall, and clear traces To save, recall, and clear traces To save traces, two trace memories are available. The following exercise shows you how to store and recall waveforms from pixel memories. 1 Connect a signal to the oscilloscope and obtain a stable display. 2 Press Trace . A softkey menu appears with trace memory selections. Trace selects trace memories Mem1 or Mem2 (Trace 1 - Trace 100 if the oscilloscope has a Measurement/Storage module installed).
Saving and Recalling the Configuration To save, recall, and clear traces 3 Select a trace memory by pressing the Trace softkey. 4 Press the Save to Mem softkey. The current oscilloscope screen and setup are copied to the selected trace memory. 5 Press the Trace Mem On softkey to display memory. The trace is displayed in half-bright video. Automatic measurements do not operate on stored traces because stored waveforms are pictorial information, rather than stored data.
Saving and Recalling the Configuration To save or recall front-panel setups To save or recall front-panel setups Ten memories are available to store front-panel setups. Saving front-panel setups can save you time in situations where several setups are repeated many times. 1 Press Setup . 2 To change the selected memory location, press either the left-most softkey or turn the Entry knob. 3 Press the Save softkey to save a front-panel setup, then press the Recall softkey to recall a front-panel setup.
Saving and Recalling the Configuration To reset the HP 54645A/D instrument setup Table 4-1 HP 54645A Factory-Preset Default Configuration Settings Configuration Item Cursors Trace memories Graticule Autostore Time base Display Channels Trigger Mode Trigger Condition Setting Cursors off; time readout is selected; all cursors are set to time/voltage zero. Both trace memory 1 and 2 are off; trace 1 memory is selected.
Saving and Recalling the Configuration To reset the HP 54645A/D instrument setup Table 4-2 HP 54645D Factory-Preset Default Configuration Settings Configuration Item Cursors Trace memories Graticule Autostore Time base Display Channels Labels Threshold Trigger Mode and Condition Edge Trigger Pattern Trigger Advanced Trigger 4-50 Setting Cursors off; time readout is selected; all cursors are set to time/voltage zero Both trace memory 1 and 2 are off; trace 1 memory is selected Grid set to Full Off Time re
Configuring the Mixed-Signal Oscilloscope This section describes how to configure the following items for the HP 54645D Mixed-Signal Oscilloscope, including changing the logic threshold for input signals. To change the logic threshold for input signals 1 Press Label/Threshold . 2 Press the Threshold Menu softkey to display the range of channels for which you want to set the logic threshold, and the available logic thresholds. 3 Press the Set softkey to select a group of digital channels.
Configuring the Mixed-Signal Oscilloscope To change the logic threshold for input signals Figure 4-19 Variable threshold softkey Logic Threshold Setup The threshold voltage setting is used by the input comparators to determine whether an input signal is a logic low or logic high. The settings for each option are shown in the following table. Table 4-3 Threshold Voltage Settings Option Voltage TTL 1.40 V CMOS 2.50 V ECL -1.30 V Variable Variable from –6.00 V to +6.
Using Labels on the Mixed-Signal Oscilloscope The HP 54645D Mixed-Signal Oscilloscope allows you to define and assign labels to each input channel. Or, you can turn labels off to increase the waveform display area. To turn the label display on or off • To display channel labels, press Label/Threshold , then press the Labels On softkey. • To turn off channel labels display, press Label/Threshold , then press the Labels Off softkey.
Using Labels on the Mixed-Signal Oscilloscope To assign a predefined label to a channel To assign a predefined label to a channel 1 Press Label/Threshold . 2 Press the Define Labels softkey. The following figure shows the label maker. A label definition menu is shown on the right-hand side of the display. 3 Select the channel for which you want to assign a label using the Select knob. You can assign labels to channels that are off and to channels that are on.
Using Labels on the Mixed-Signal Oscilloscope To assign a predefined label to a channel If you defined a new label, it is added to the non-volatile label list and will be saved with the oscilloscope configuration. Figure 4-20 The entry field shows you what will be assigned to the channel. Scroll through the label and character lists using the Entry knob. Shows what will be put in the entry field when you press Copy. Select the channel with the Select knob.
Using Labels on the Mixed-Signal Oscilloscope To define a new label Label List Management The label list contains 75 of the most recently used labels. The list does not save duplicate labels, nor does it save multiple labels that differ by, at most, two trailing numeric characters. The label list is non-volatile. Thus, after you use the label list for a while, your labels will predominate, making it easier to customize the instrument display for your needs.
Using Labels on the Mixed-Signal Oscilloscope To define a new label 4 To enter characters into the new label: a Press the Position softkey until the cursor position in the entry field corresponds to the point where you want to replace a character. b Enter or delete a character. • To enter a character, use the Entry Knob to choose a character from the character list. Then press the Copy softkey. • To insert a space, press the Insert Space softkey.
Using Labels on the Mixed-Signal Oscilloscope To initialize the label list To initialize the label list 1 Press Label/Threshold . 2 Press the Initialize Label List softkey. A message appears, warning you that this operation will overwrite the current label list. • To confirm the operation, press the Yes softkey. You will be prompted to press Yes again to initiate the operation. • To cancel the operation, press the No softkey.
5 Making Measurements with HP 54645A/D Oscilloscopes
Making Measurements with HP 54645A/D Oscilloscopes By now you are familiar with the VERTICAL/ANALOG, HORIZONTAL, and TRIGGER groups of the front-panel keys. You should also know how to determine the setup of the oscilloscope by looking at the status line. We recommend you perform all of the following exercises so you become familiar with the powerful measurement capabilities of the oscilloscope.
Capturing Data In the HP 54645A Oscilloscope, an 8-bit A/D converter converts the input waveform into an evenly-spaced series of voltage readings. These readings are made once for each sample, and are stored into memory in time-voltage pairs. Main and Delayed Sweep The delayed sweep display function magnifies the contents of sample memory—data used by the main and delayed sweep windows is acquired on a single acquisition; the data corresponds to the same trigger event.
Making Measurements with HP 54645A/D Oscilloscopes To use delayed sweep To use delayed sweep You can use the delayed sweep window to locate and horizontally expand part of the main sweep for a more detailed (high-resolution) analysis of signals. The following steps show you how to use delayed sweep. These steps are similar to operating the delayed sweep in analog oscilloscopes. 1 Connect a signal to the oscilloscope and obtain a stable display. 2 Press Main/Delayed . 3 Press the Delayed softkey.
Making Measurements with HP 54645A/D Oscilloscopes To use delayed sweep The screen divides in half. The top half displays the main sweep, and the bottom half displays an expanded portion of the main sweep. This expanded portion of the main sweep is called the delayed sweep. The top half also has two solid vertical lines called markers. These markers show what portion of the main sweep is expanded in the lower half.
Making Measurements with HP 54645A/D Oscilloscopes To view asynchronous noise on a signal To view asynchronous noise on a signal The following exercise shows how to use the oscilloscope to view asynchronous noise on a signal that is not synchronous to the period of the waveform. 1 Connect a noisy signal to the oscilloscope and obtain a stable display. This shows a waveform with asynchronous noise in the pulse.
Making Measurements with HP 54645A/D Oscilloscopes To view asynchronous noise on a signal 2 Press Autostore . Notice that STORE is displayed in the status line. 3 Set the trigger mode to normal, then adjust the trigger level into the noise region of the signal. 4 Decrease the sweep speed for better resolution of the asynchronous noise. Pan and zoom the waveform to view signal details. To characterize the asynchronous noise signal, use the cursors.
Making Measurements with HP 54645A/D Oscilloscopes To reduce the random noise on a signal To reduce the random noise on a signal If the signal you are applying to the oscilloscope is noisy, you can set up the oscilloscope to reduce the noise on the waveform. First, you stabilize the displayed waveform by removing the noise from the trigger path. Second, you reduce the noise on the displayed waveform. 1 Connect a signal to the oscilloscope and obtain a stable display.
Making Measurements with HP 54645A/D Oscilloscopes To reduce the random noise on a signal Low-frequency reject (LF reject) adds a high-pass filter with the 3-dB point at 50 kHz. Use LF reject to remove low-frequency signals, such as power line noise, from the trigger path. Figure 5-5 0 dB 3 dB down point Pass Band dc 50 kHz LF Reject Noise reject increases the trigger hysteresis band. By increasing the trigger hysteresis band, you reduce the possibility of triggering on noise.
Making Measurements with HP 54645A/D Oscilloscopes To reduce the random noise on a signal 3 Use averaging to reduce noise on the displayed waveform. • Press Display , then press Average. Notice that Av appears in the status line. • Toggle the # Average softkey to select the number of averages that best eliminates the noise from the displayed waveform. Av in the status line indicates how much of the averaging process is finished, by turning to inverse video as the oscilloscope performs averaging.
Making Measurements with HP 54645A/D Oscilloscopes To capture glitches or narrow pulses with peak detect To capture glitches or narrow pulses with peak detect A glitch is a rapid change in the waveform that is usually narrow as compared to the waveform. Peak detect mode displays any signal wider than 5 ns, allowing you to find glitches and narrow spikes regardless of the sweep speed. To capture glitches or narrow pulses: 1 Connect a signal to the oscilloscope and obtain a stable display. 2 Find the glitch.
Making Measurements with HP 54645A/D Oscilloscopes To use channel math 3 Characterize the glitch with delayed sweep. To characterize the glitch with delayed sweep, follow these steps: • Press Main/Delayed . Press the Delayed softkey. • To obtain a better resolution of the glitch, expand the time base. • Use the Delay knob to pan through the waveform to set the expanded portion of the main sweep over the glitch.
Making Measurements with HP 54645A/D Oscilloscopes To use the Roll display mode With the Measurement/Storage module installed, two functions define these operations that create mathematically altered waveforms (not pixel math): • Function 1 will add, subtract, or multiply the signals acquired on vertical inputs 1 and 2, then will display the result as F1. • Function 2 will integrate, differentiate, or perform an FFT on the signal acquired on input 1, input 2, or the result in F1.
Making Measurements with HP 54645A/D Oscilloscopes To use the XY display mode To use the XY display mode The XY display mode converts the oscilloscope from a volts-versus-time display to a volts-versus-volts display. You can use various transducers so the display could show strain versus displacement, flow versus pressure, volts versus current, or voltage versus frequency.
Making Measurements with HP 54645A/D Oscilloscopes To use the XY display mode Figure 5-9 Signal Centered on the Display 4 Press Cursors . 5 Set the Y2 cursor to the top of the signal, and set Y1 to the bottom of the signal. Note the ∆Y value at the bottom of the display. In this example, we are using the Y cursors, but you could have used the X cursors instead. If you use the X cursors, make sure you center the signal in the Y axis.
Making Measurements with HP 54645A/D Oscilloscopes To use the XY display mode Figure 5-11 Cursors Set to Center of Signal 6 Move the Y1 and Y2 cursors to the center of the signal. Again, note the ∆Y value. 7 Calculate the phase difference using the formula below. sin θ = second ∆Y 111.9 = = 27.25 degrees of phase shift. 244.4 first ∆Y XY Display Mode Operating Hint When you select the XY display mode, the time base is turned off.
Making Measurements with HP 54645A/D Oscilloscopes To use the XY display mode Figure 5-12 Signals are 90° Out of Phase Figure 5-13 Signals are In Phase 5-17
Making Measurements with HP 54645A/D Oscilloscopes To analyze video waveforms To analyze video waveforms The TV sync separator in the oscilloscope has an internal clamp circuit. This removes the need for external clamping when you are viewing unclamped video signals. TV triggering requires two vertical divisions of display, either channel 1 or channel 2 as the trigger source, and the selection of internal trigger.
Making Measurements with HP 54645A/D Oscilloscopes To analyze video waveforms 5 Set the time base to 200 µs/div, then center the signal on the display with the Delay knob (delay about 800 µs). 6 Press Main/Delayed , then press the Delayed softkey. Pan and zoom the waveform to view signal details. 7 Set the delayed sweep to 20 µs/div, then set the expanded portion over the VITS (delay about 900 µs).
Making Measurements with HP 54645A/D Oscilloscopes To analyze video waveforms 8 Press Main/Delayed , then press the Main softkey. 9 Use the horizontal vernier to change the time base to 1 µs/div, then center the signal on the display with the Delay knob (delay about 901 µs). Figure 5-15 Modulated 12.
Making Measurements with HP 54645A/D Oscilloscopes To analyze video waveforms Triggering on both TV Fields at the Same Time The HP 54645A/D Oscilloscopes can trigger on the vertical sync pulse in both TV fields at the same time. This allows you to view noninterlaced video signals which are common in today’s computer monitors. To trigger on both sync pulses, press Field 1 and Field 2 at the same time, or press Vertical (HP 54645A).
Measuring Waveform Data With the HP 54645A/D Oscilloscopes, you can measure waveform data using Voltage, Time, and Cursor keys. This section shows you how. To make cursor measurements The following steps guide you through the front-panel Cursors key. You can use the cursors to make custom voltage or time measurements on the signal. 1 Connect a signal to the oscilloscope and obtain a stable display. 2 Press Cursors .
Making Measurements with HP 54645A/D Oscilloscopes To make cursor measurements Use the Entry knob to move the cursors. You can toggle the active cursor by pressing the cursor key while in the cursors menu. Cursor measurements are not bound to the edge of the screen. If you set a cursor, then pan and zoom the waveform until that cursor is off the screen, when you set the other cursor, the measurement will still be accurate.
Making Measurements with HP 54645A/D Oscilloscopes To make cursor measurements Figure 5-18 Cursors Track Delayed Sweep Expand the display with delayed sweep, then characterize the event of interest with the cursors.
Making Measurements with HP 54645A/D Oscilloscopes To make cursor measurements Figure 5-19 Moving Cursors Together Pressing the time cursor softkey until both time cursors are highlighted allows you to move them together when rotating the Entry knob. Figure 5-20 Checking Pulse Width Variations Move the cursors together to check for pulse width variations in a pulse train.
Making Measurements with HP 54645A/D Oscilloscopes To make frequency measurements automatically To make frequency measurements automatically The automatic measurement capability of the HP 54645A/D Oscilloscopes allows you to easily make frequency measurements. 1 Connect a signal to the oscilloscope and obtain a stable display. 2 Press Time . The first softkey menu appears with frequency, period, and duty cycle measurement choices.
Making Measurements with HP 54645A/D Oscilloscopes To make frequency measurements automatically • To find the Show Meas softkey, press the Next Menu softkey key. When the Show Meas softkey is turned on, cursors are displayed on the waveform, and show measurement points for the measurement result displayed on the right-most part of the status line. If you select more than one measurement, you can show a previous measurement by reselecting the measurement.
Making Measurements with HP 54645A/D Oscilloscopes To make time measurements automatically To make time measurements automatically You can measure the following time parameters with the oscilloscope: frequency, period, duty cycle, positive and negative widths, rise time, and fall time. The following exercise guides you through the time keys by making a rise-time measurement. Steps for making other measurements are included at the end of the procedure.
Making Measurements with HP 54645A/D Oscilloscopes To make time measurements automatically 2 Press Time . The first softkey menu appears with frequency, period, and duty cycle measurement choices. Source selects channel 1 or 2 for the time measurement. Time Measurements include frequency, period, and duty cycle. These measurements are made at the 50% levels. Clear Meas (clear measurement) erases the measurement results and removes the cursors from the display.
Making Measurements with HP 54645A/D Oscilloscopes To make time measurements automatically 4 Press the Rise Time softkey. The oscilloscope automatically measures the rise time of the signal and displays the result on the display. Automatic Measurements The oscilloscope makes automatic measurements on the first displayed event. The following figure shows how to use delayed sweep to isolate an edge for a rise-time measurement.
Making Measurements with HP 54645A/D Oscilloscopes To make time measurements automatically To measure the duty cycle • Press Next Menu until you find the Duty Cy softkey, and press it. To measure the pulse widths 1 To measure the positive pulse width, press Next Menu until you find the +Width softkey, and press it. Figure 5-24 Positive Width Measurement on HP 54645D Digital Channels 2 To measure the negative pulse width, press Next Menu until you find the -Width softkey, and press it.
Making Measurements with HP 54645A/D Oscilloscopes To make voltage measurements automatically To make voltage measurements automatically You can measure the following voltage parameters automatically with the oscilloscope: peak-to-peak, average, rms, maximum, minimum, top, base, amplitude, overshoot, and preshoot. The following exercise guides you through the Voltage keys by making an rms voltage measurement. Steps for making other voltage measurements are included at the end of the procedure.
Making Measurements with HP 54645A/D Oscilloscopes To make voltage measurements automatically Voltage Measurements Voltage measurements do not work on digital channels on HP 54645D. 1 Connect a signal to the oscilloscope and obtain a stable display. 2 Press Voltage . A softkey menu appears with voltage measurement choices. Source selects a channel for the voltage measurement. Voltage Measurements include peak-to-peak (Vp-p), average (Vavg), and root mean square (Vrms).
Making Measurements with HP 54645A/D Oscilloscopes To make voltage measurements automatically Figure 5-27 Isolating Area for Vtop Voltage Measurement 4 Press the Next Menu softkey. A softkey menu appears with additional voltage measurement choices. Show Meas (show measurement) displays the horizontal and vertical cursors showing where the measurement was taken. Voltage Measurements include choices for measuring the maximum (Vmax), minimum (Vmin), top (Vtop), and base (Vbase) voltages.
6 Using Option 005 Enhanced TV/Video Trigger (HP 54645A)
Using Option 005 Enhanced TV/Video Trigger You can use the Option 005 Enhanced TV/Video trigger with the HP 54645A Oscilloscope. One of the first things you will want to do with your oscilloscope’s new Option 005 Enhanced TV/Video trigger is to become acquainted with its menu choices. Therefore, we have written the exercises in this chapter to familiarize you with its basic controls. To use the TV/Video trigger, you must be familiar with your oscilloscope.
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) Option 005 gives you an Enhanced TV/Video Trigger for the HP 54645A Oscilloscope, allowing highly detailed analysis of TV waveforms.
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To autoscale on a video signal To autoscale on a video signal 1 Use a cable to connect a TV signal to channel 1. 2 Press Slope/Glitch in the TRIGGER section of the front panel, and select the TV softkey as your trigger mode. 3 To select a TV standard, press the TV Menu softkey, then press the Standard softkey to select the TV standard. Your choices are NTSC, PAL, SECAM, and GENERIC. GENERIC is used for other TV/Video standards.
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To trigger on a specific line of video To trigger on a specific line of video TV triggering requires greater than 1/4 division of sync amplitude, either channel 1 or channel 2 as the trigger source. Turning the trigger level knob in TV trigger does not change the trigger level because the trigger level is automatically set to the sync pulse tips.
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To trigger on a specific line of video Figure 6-1 Triggering on Line 71 Note the TV Grid displayed (selected from the Display menu).
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To trigger on all TV line sync pulses To trigger on all TV line sync pulses To quickly find maximum video levels, you could trigger on all TV line sync pulses. When All Lines is selected as the TV trigger mode, the oscilloscope will trigger on the first line that it finds when the acquisition starts. 1 Select the TV display, TV as the trigger mode, and the appropriate TV standard as described in the previous section, "To autoscale on a video signal.
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To trigger on a specific field of the video signal To trigger on a specific field of the video signal To examine the components of a video signal, trigger on either Field 1 or Field 2. When a specific field is selected, the oscilloscope triggers on the rising edge of the first serration pulse in the vertical sync interval in the specified field (1 or 2).
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To trigger on all fields of the video signal To trigger on all fields of the video signal To quickly and easily view transitions between fields, or to find the amplitude differences between the fields, use the All Fields trigger. The oscilloscope will trigger on the first field it finds at the start of acquisition.
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To trigger on odd or even fields To trigger on odd or even fields To check the envelope of your video signals, or to measure worst case distortion, trigger on the odd or even fields. When Field 1 is selected, the oscilloscope triggers on color fields 1 or 3. When Field 2 is selected, the oscilloscope triggers on color fields 2 or 4.
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To trigger on odd or even fields If a more detailed analysis is required, then only one color field should be selected to be the trigger. You can do this by using the oscilloscope’s holdoff control. Using the holdoff settings shown in the following table, the oscilloscope will now trigger on color field 1 OR color field 3 when Field 1 is selected. This is known as odd field selection. Even fields will be selected with Field 2.
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To analyze video waveforms with Option 005 To analyze video waveforms with Option 005 The combination of the TV trigger, delayed sweep, and automatic measurements allow this oscilloscope to precisely analyze video waveforms. There is no need for external clamping to obtain a stable trigger when you are viewing unclamped video signals. This is because the TV sync separator in the oscilloscope has an internal clamp circuit in the trigger path.
Using Option 005 Enhanced TV/Video Trigger (HP 54645A) To analyze video waveforms with Option 005 5 Set the time base to 200 µs/div, then center the signal on the display with the delay knob (delay about 800 µs). 6 Press Main/Delayed , then press the Delayed softkey. 7 Set the delayed sweep to 20 µs/div, then set the expanded portion over the VITS (delay about 988.8 µs). Figure 6-7 Second VITS Displayed This figure shows the second vertical interval test signals displayed with delayed sweep.
6-14
7 Testing, Adjusting, and Troubleshooting
Testing, Adjusting, and Troubleshooting This chapter explains the general procedures for solving problems, verifying correct oscilloscope operation, adjusting the oscilloscope display and power supply, correcting malfunctions in the oscilloscope, and performing tests to ensure that the oscilloscope meets performance specifications. It also describes how to verify operation of the Option 005 Enhanced TV/Video Trigger board, along with information for adjusting the offset, and troubleshooting.
Solving Problems with HP 54645A/D Oscilloscopes This chapter describes possible solutions if you encounter problems while making measurements with HP 54645A/D Oscilloscopes. If you need to replace parts, refer to chapter 8, “Replacement Parts.
Testing, Adjusting, and Troubleshooting If there is no trace display If there is no trace display Check that the power cord is connected to the oscilloscope and to a live power source. Check that the front-panel power switch is set to 1 (on). Check that the display is illuminated and that the brightness is adjusted correctly. If there is no display, see the troubleshooting procedures in this chapter.
Testing, Adjusting, and Troubleshooting If the trace display is unusual or unexpected If the trace display is unusual or unexpected Check that the Time/Div setting is correct for the expected frequency range of the input signals. The sampling speed of the oscilloscope depends on the Time/Div setting. Thus, when the Time/Div setting is slower than 1 µs/div, the oscilloscope may be sampling too slowly to capture all the transitions on the waveform.
Testing, Adjusting, and Troubleshooting If you can’t get any response from the oscilloscope Check that the grabbers are securely connected to the nodes in the circuit under test. Check that the circuit under test is powered on. You may have pressed Autoscale with no input signal available. Performing the checks described above ensures that the signals from the circuit under test are seen by the oscilloscope. Check that the desired channels are on. 1 Press On/Off.
Getting Service If the oscilloscope is under warranty, you must return it to Hewlett-Packard for all service work covered by the warranty. See "To return the oscilloscope to Hewlett-Packard." If the warranty period has expired, you can still return the oscilloscope to Hewlett-Packard for all service work. Contact your nearest Hewlett-Packard Sales Office for additional details on service work.
Testing, Adjusting, and Troubleshooting To return the oscilloscope to Hewlett-Packard To return the oscilloscope to Hewlett-Packard Before shipping the oscilloscope to Hewlett-Packard, contact your nearest Hewlett-Packard Sales Office for additional details. 1 Write the following information on a tag and attach it to the oscilloscope. • • • • Name and address of owner Model number Serial number Description of service required or failure indications 2 Remove all accessories from the oscilloscope.
Verifying Oscilloscope Performance To completely test and troubleshoot the oscilloscope, you will need to fabricate two test accessories: • The test connectors make it easy to hook the oscilloscope probes to function generators and measurement equipment with minimum electrical distortion. These connectors are used in the threshold and time interval tests. • The dummy load is used to troubleshoot the power supply. Refer to “To construct your own dummy load” later in this chapter.
Testing, Adjusting, and Troubleshooting To construct test connectors for digital channels 1 Build the first test connector using a BNC connector and an 8-by-2 section of Berg strip. a Solder a jumper wire to all pins on one side of the Berg strip. b Solder a jumper wire to all pins on the other side of the Berg strip. c Solder the center of the BNC connector to the center pin of one row on the Berg strip. d Solder the ground tab of the BNC connector to the center pin of the other row on the Berg strip.
Testing, Adjusting, and Troubleshooting To test the digital channels To test the digital channels Instructions for HP 54645D These instructions apply only to the HP 54645D Mixed-Signal Oscilloscope. Testing the acquisition system does not check a specification, but does provide confidence that the system is functioning correctly. 1 Disconnect probes from the circuit under test or other input source.
Testing Threshold Accuracy Instructions for HP 54645D These instructions apply only to the HP 54645D Mixed-Signal Oscilloscope. Testing the threshold accuracy verifies the data channel threshold accuracy specification. You should perform this test every 24 months or 4000 hours of operation, whichever comes first. These instructions include detailed steps for testing the threshold settings of digital channels D0-D7. After testing digital channels D0-D7, connect and test digital channels D8-D15.
Testing, Adjusting, and Troubleshooting To set up and connect the equipment To set up and connect the equipment Instructions for HP 54645D These instructions apply only to the HP 54645D Mixed-Signal Oscilloscope. 1 Turn on the test equipment and the oscilloscope. Let them warm up for 30 minutes before beginning the test. 2 Set up the function generator. a Set up the function generator to provide a DC offset voltage at the Main Signal output.
Testing, Adjusting, and Troubleshooting To verify threshold accuracy To verify threshold accuracy Instructions for HP 54645D These instructions apply only to the HP 54645D Mixed-Signal Oscilloscope. 1 Press Label/Threshold . Select Threshold Menu, and select D0-D7 under the Set softkey. Then, select the variable threshold softkey just to the right of ECL.
Testing, Adjusting, and Troubleshooting To check the output of the CALIBRATOR To check the output of the CALIBRATOR In this test, you measure the output of the rear-panel DC CALIBRATOR OUTPUT with a multimeter. The CALIBRATOR is used for self-calibration of the HP 54645A/D. The accuracy of the CALIBRATOR is not specified, but it must be within the test limits to provide for accurate self-calibration. The CALIBRATOR output produces DC voltages between 0 and 5V during vertical calibration.
Testing, Adjusting, and Troubleshooting To verify voltage measurement accuracy To verify voltage measurement accuracy In this test, you verify the voltage measurement accuracy by measuring the output of a power supply using dual cursors on the oscilloscope, and comparing the results with a multimeter. Test limits: ±1.5% of full scale ± 1 LSB* Full scale is defined as 16 mV on the 1 mV/div range. Full scale on all other ranges is defined as 8 divisions times the V/div setting. * 1 LSB = 0.
Testing, Adjusting, and Troubleshooting To verify voltage measurement accuracy 1 Set up the oscilloscope. a Press Setup , then press the Default Setup softkey. b Adjust the channel 1 Position knob to place the baseline at approximately 0.5 division from the bottom of the display. Channel 1 is labeled "1" on HP 54645A and "A1" on HP 54645D. c Set the Volts/Div to the first line of the following table. d Press Display . Then press the Average softkey and set # Average to 64.
Testing, Adjusting, and Troubleshooting To verify voltage measurement accuracy 7 Continue checking the voltage measurement accuracy with the remaining power supply setting lines in the following table. Table 7-6 Voltage Measurement Accuracy Volts/Div setting Power supply setting Test limits 5 V/Div 35 V 34.24 V to 35.76 V 2 V/Div 14 V 13.696 V to 14.304 V 1 V/Div 7V 6.848 V to 7.152 V 0.5 V/Div 3.5 V 3.424 V to 3.576 V 0.2 V/Div 1.4 V 1.3696 V to 1.4304 V 0.
Testing, Adjusting, and Troubleshooting To verify bandwidth To verify bandwidth In this test you verify bandwidth by using a power meter and power sensor to set output of a signal generator at 1 MHz and at 100 MHz. You use the peak-to-peak voltage at 1 MHz and at 100 MHz to verify the bandwidth response of the oscilloscope. The test is repeated at 5 mV/div (75-MHz bandwidth).
Testing, Adjusting, and Troubleshooting To verify bandwidth 1 Connect the equipment. a Connect the signal generator to the input of the power splitter. b Connect the power sensor to one output of the power splitter, and connect channel 1 of the oscilloscope to the other power splitter output. Put a 50-Ω feedthrough at the input of the oscilloscope. Channel 1 is labeled "1" on HP 54645A and "A1" on HP 54645D. 2 Set up the oscilloscope. a Press Setup , then press the Default Setup softkey.
Testing, Adjusting, and Troubleshooting To verify bandwidth 8 Change the time base to 5 ns/div. Wait a few seconds for the measurement to settle (the Av letters in the status line indicate how much of the averaging process is finished by turning to inverse video as the oscilloscope performs averaging), then note the Vp-p reading from the bottom of the display. Vp-p = ______ mV. 9 Calculate the response using the following formula.
Testing, Adjusting, and Troubleshooting To verify horizontal ∆t and 1/∆t accuracy To verify horizontal ∆t and 1/∆t accuracy In this test, you verify the horizontal ∆t and 1/∆t accuracy by measuring the output of a time mark generator with the oscilloscope. Test limits: ±0.01% ±0.
Testing, Adjusting, and Troubleshooting To verify horizontal ∆t and 1/∆t accuracy 5 Press Time , then press the Freq and Period softkeys. You should measure the following: Frequency 1 MHz, test limits are 995.9 kHz to 1.0042 MHz. Period 1 µs, test limits are 995.9 ns to 1.0041 µs. If the measurements are not within the test limits, see "Troubleshooting the Oscilloscope." 6 Change the time mark generator to 10 ns, and change the time base to 5 ns/div. Adjust the trigger level to obtain a stable display.
Testing, Adjusting, and Troubleshooting To verify trigger sensitivity To verify trigger sensitivity In this test, you verify the trigger sensitivity by applying 25 MHz to the oscilloscope. The amplitude of the signal is decreased to the specified levels, then you check to see if the oscilloscope is still triggered. You then repeat the process at the upper bandwidth limit.
Testing, Adjusting, and Troubleshooting To verify trigger sensitivity Internal Trig Sensitivity 1 Press Setup , then press Default Setup. 2 Connect the signal generator to channel 1 using a 50-Ω feedthrough at the oscilloscope input. Channel 1 is labeled "1" on HP 54645A and "A1" on HP 54645D. 3 Verify the trigger sensitivity at 25 MHz and 0.35 divisions. a Set the signal generator to 25 MHz and about 100 mV. b Press Autoscale . c Set the time base to 50 ns/div. d Set channel 1 to 100 mV/div.
Testing, Adjusting, and Troubleshooting To verify trigger sensitivity External Trig Sensitivity 6 Verify the external trigger sensitivity at 100 MHz, 100 mVp-p and at 25 MHz, 50 mVp-p. Instructions for HP 54645A Only This procedure applies only to the HP 54645A Oscilloscope. a Using the power splitter, connect the signal generator to the b c d e f g h i channel 1 input and to the external trigger input. Use the 50-Ω feedthroughs at the oscilloscope inputs.
Testing, Adjusting, and Troubleshooting To verify vertical output on Option 005 To verify vertical output on Option 005 This section applies only to the Option 005 Enhanced TV/Video Trigger. In this test, we will use the oscilloscope’s channel 2 to measure the amplitude of the vertical output signal. Test limits: approximately 90 mVp-p into 50 Ω with a full-screen input.
HP 54645A/D Performance Test Record Serial No. ______________________________________ Test Interval ____________________________________ Recommended Next Testing _______________________ Test by____________________________ Work Order No._____________________ Temperature _______________________ Threshold Accuracy ± (100 mV + 3% of threshold setting) Test Specification Limits Ch D0-D7 Calibrator Output dc +5 V – 250 mV +5 V + 250 mV –5 V – 250 mV –5 V + 250 mV 0 V – 100 mV 0 V + 100 mV +4.750 V +5.
Adjusting the Oscilloscope This section explains how to adjust the oscilloscope so that it is at optimum operating performance. You should perform the hardware adjustments and Self Cal periodically as indicated in this section. • Perform hardware adjustments at 12 months or 2,000 hours of operation. • Perform Self Cal at 6 months or 1000 hours of operation, or if ambient temperature is greater than 10 °C from the calibration temperature, or if the user wants to maximize the measurement accuracy.
Testing, Adjusting, and Troubleshooting To adjust the power supply To adjust the power supply The power supply has a +5.1 V adjustment and a –5.25 V adjustment. The other voltages are based on the +5.1 V adjustment. In this procedure you use a multimeter to measure the +5.1 V and –5.25 V, and if necessary, adjust the power supplies to within tolerance. Table 7-11 Equipment Required Equipment Critical specifications Digital multimeter 0.1 mV resolution, accuracy ±0.
Testing, Adjusting, and Troubleshooting To adjust the power supply 2 Measure the power supply voltages at E1 through E6 on the system board. The test points are not marked on the system board; see the following figure for the location of test points. Make sure that the voltage measurements are within the following tolerances. Table 7-12 Power Supply Voltage Tolerances Supply Voltage +5.1 V –5.25 V +15.75 V − 15.75 V Tolerance ±153 mV (+4.947 V to +5.253 V) ±158 mV (–5.092 V to –5.408 V) +1.
Testing, Adjusting, and Troubleshooting To adjust the power supply If the +5.1 V measurement is out of tolerance, adjust the +5.1 V adjustment on the power supply; if the –5.25 V measurement is out of tolerance, adjust the –5.25 V adjustment on the power supply (see the following figure). The ±15.75 V supplies are not adjustable and are dependent upon the +5.1 V supply. If adjusting the power supply does not bring all the voltages within tolerance, see "Troubleshooting the Oscilloscope" in this chapter.
Testing, Adjusting, and Troubleshooting To perform the self-calibration To perform the self-calibration In this procedure, you load the default calibration factors to give a known starting point for the firmware calibration. However, once the default calibration factors are loaded, you must perform the remainder of the firmware calibration to maintain the accuracy of the oscilloscope.
Testing, Adjusting, and Troubleshooting To perform the self-calibration 1 Check the rear panel CALIBRATOR output level. If you are not sure how to check the CALIBRATOR, see "To check the output of the CALIBRATOR." 2 Load the default calibration factors. a Set the rear-panel CALIBRATION switch to the UNPROTECTED position. b Press Print/Utility . Then press Service Menu and Self Cal Menu. c Press the Load Defaults softkey.
Testing, Adjusting, and Troubleshooting To adjust the low-frequency compensation To adjust the low-frequency compensation In this procedure, you adjust the low-frequency compensation adjustment for each channel.
Testing, Adjusting, and Troubleshooting To adjust the high-frequency pulse response 6 Adjust the channel 1 low-frequency compensation adjustment for as flat a pulse top as possible. Channel 1 is labeled "1" on HP 54645A and "A1" on HP 54645D. 7 Repeat steps 1 through 6 for channel 2. Channel 2 is labeled "2" on HP 54645A and "A2" on HP 54645D.
Testing, Adjusting, and Troubleshooting To adjust the high-frequency pulse response 1 Connect the pulse generator to channel 1, using a 50-Ω feedthrough at the oscilloscope input. Channel 1 is labeled "1" on HP 54645A and "A1" on HP 54645D. 2 Press Autoscale . 3 Change the time base to 10 ns/div. 4 Press 1 on the HP 54645A, or A1 on the HP 54645D, then toggle the Vernier softkey to On. 5 Adjust the Volts/Div until there are about 6 divisions of vertical deflection.
Testing, Adjusting, and Troubleshooting To adjust the display To adjust the display The display adjustments are optional and normally do not require adjustment. You should use this procedure only for the few cases when the display is obviously out of adjustment. Equipment Required Table 7-16 Equipment Critical specifications Digital multimeter Accuracy ±0.
Testing, Adjusting, and Troubleshooting To adjust the display 8 Adjust HB Cont (half-bright contrast) for the best contrast between the half-bright and full-bright blocks. You can re-adjust Sub Bri, intensity control, and HB Cont to suit your preference. 9 Press any key to continue to the next test pattern. Then, adjust H.Hold (horizontal hold) to center the display horizontally. 10 Adjust Focus for the best focus. 11 Press any key to continue to the normal display pattern. Then adjust V.
Testing, Adjusting, and Troubleshooting To adjust the Option 005 offset (R15) (HP 54645A) To adjust the Option 005 offset (R15) (HP 54645A) On the Option 005 board, there is only one adjustment. You must calibrate the oscilloscope before performing this adjustment. You must also remove the cabinet to access R15. Refer to chapter 8, “Replacement Parts,” for instructions on how to remove the cabinet to gain access to R15.
Troubleshooting the Oscilloscope The service policy for this instrument is replacement of defective assemblies. The following procedures can help isolate problems to the defective assembly. WARNING CAUTION CAUTION The maintenance described in this section is performed with power supplied to the oscilloscope and with the protective covers removed. Only trained service personnel who are aware of the hazards involved should perform the maintenance.
Testing, Adjusting, and Troubleshooting To construct your own dummy load To construct your own dummy load 1 Obtain a connector that is compatible with the connector J3 on the Low Voltage Power Supply. 2 Connect the following load resistors to the connector: +5.1 V requires a 4-A load, 1.3 Ω and 20.4 W on pins 9–12. –5.25 V requires a 3-A load, 1.75 Ω and 15.8 W on pins 15–18. +15.75 V requires a 1.3-A load, 12.2 Ω and 20.5 W on pins 5–6. –15.75 V requires a 0.8 A-load, 19.7 Ω and 13 W on pin 3.
Testing, Adjusting, and Troubleshooting To check out the oscilloscope To check out the oscilloscope 1 Is there an interface module connected to the rear panel of the oscilloscope? If yes, do the following steps. If not, go to step 2. a Turn off the oscilloscope. b Remove the module. c Turn on the oscilloscope, then check for the failing symptom. If the failing symptom disappears, replace the module. If not, go to step 2. 2 Turn off the oscilloscope for 30 seconds minimum and then turn it on again.
Testing, Adjusting, and Troubleshooting To check out the oscilloscope 6 Disconnect the ribbon cable from the display board, then check the following signals on the system board. Table 7-19 Display Signals Signal Name Frequency Pulse width Voltage U5 Pin 36 U76 Pin 1 (HP 54645A) U77 Pin 1 (HP 54645D) U5 Pin 2 DE Hsync 19.72 kHz 19.72 kHz 38.0 µs 3.0 µs 2.6 Vp-p 5.0 Vp-p Vsync 60.00 Hz 253.5 µs 5.2 Vp-p If the signals are good, replace the display assembly. If not, replace the system board.
Testing, Adjusting, and Troubleshooting To check out the oscilloscope 9 Is the fan running? If yes, go to "To run the internal self-tests." If not, do the steps below. The Low Voltage Power Supply has a thermal cut-out circuit. If the fan is defective, the Low Voltage Power Supply shuts down when it gets too hot for safe operation. a Disconnect the fan cable from the power supply. b Measure the fan voltage at the connector on the power supply. See the following figure for location of the fan connector.
Testing, Adjusting, and Troubleshooting To clear error messages To clear error messages One or more of the following error messages may appear on the display (within the graticule space) as a result of internal NVRAM (non-volatile random access memory.) 1 If the message "Vertical Cal factors failed checksum test–defaults loaded" appears on the screen, go to "To perform the self-calibration," perform steps 1 through 5, then continue the steps below.
Testing, Adjusting, and Troubleshooting To clear error messages 3 If any Fail message appears on the display after cycling power: a Press any menu key and cycle the power on the oscilloscope again. b Hold the menu key down until the message "Key-down power-up executed" is displayed. c If the original fail message still appears, contact your HP Service Center for diagnosis and repair. 4 Continue with "To check out the oscilloscope.
Testing, Adjusting, and Troubleshooting To check the Low Voltage Power Supply To check the Low Voltage Power Supply 1 Disconnect the power cord, remove the cover and set the oscilloscope on its side. CAUTION If you operate the oscilloscope without the cabinet, use an external fan to blow air across the system board. This air flow is necessary to cool the heat sinks on the system board. 2 Connect the negative lead of the multimeter to a ground point on the oscilloscope.
Testing, Adjusting, and Troubleshooting To check the Low Voltage Power Supply If the +5.1 V measurement is out of tolerance, adjust the +5.1 V adjustment on the power supply; if the –5.25 V measurement is out of tolerance, adjust the –5.25 V adjustment on the power supply. The ±15.75 V supplies are not adjustable and are dependent upon the +5.1 V supply. Blown fuse If the power supply fuse is blown, the power supply is defective. Replace the power supply.
Testing, Adjusting, and Troubleshooting To run the internal self-tests To run the internal self-tests 1 Perform the display test. a Press Print/Utility . b Press Service Menu, then Self Tst Menu and Display. c Do the half-bright and full-bright squares appear? If yes, continue with the steps below. If not, replace the display. d Press any key to continue. e Do squares appear in the four corners? If yes, the display is good. If not, replace the display. f Press any key to end the test.
Testing, Adjusting, and Troubleshooting To run the internal self-tests 4 Perform the ROM test a Press the ROM softkey. b Does the display message say "Scope self-test passed"? If yes, press any key to continue. If not (the display message says Scope self-test Failed), replace the system board. 5 Perform the RAM test. a Press the RAM softkey. b Does the display message say "Scope self-test passed"? If yes, press any key to continue.
Testing, Adjusting, and Troubleshooting To troubleshoot Option 005 To troubleshoot Option 005 To isolate a malfunction to the Option 005 board, do the following: 1 Disconnect the three cables that connect the Option 005 board to the system board. 2 Verify proper oscilloscope operation, as described in this chapter. 3 If the oscilloscope passes the performance verification and the malfunction still occurs when the Option 005 board is reconnected, then you should replace the Option 005 board.
8 Replacement Parts
Replacement Parts This chapter contains instructions for removing and ordering replaceable assemblies. Also included is a parts list for the assemblies and hardware of the oscilloscope that you can order from Hewlett-Packard. Before working on the oscilloscope, read the safety summary at the back of this book. WARNING CAUTION CAUTION Hazardous voltages are on the CRT, power supply, and display sweep board. To avoid electrical shock, disconnect the power cord from the oscilloscope.
Removing and Replacing Assemblies Refer to the exploded view of the oscilloscope in this chapter for details on how the oscilloscope fits together. To install an assembly, follow the instructions in reverse order. You will need the following tools to disassemble the oscilloscope: • T15 TORX driver to remove the oscilloscope from the cabinet and to remove the fan. • T10 TORX driver to remove the assemblies from the deck.
Replacement Parts To remove the cabinet To remove the cabinet 1 Turn off the oscilloscope and disconnect the power cable. 2 If a module is installed, remove it from the oscilloscope. 3 Using the T15 TORX driver, remove the two screws from the rear of the cabinet. 4 Using your thumbs, gently push on the rear-panel connector to slide the oscilloscope out of the cabinet. To remove the fan 1 Disconnect the fan cable from the power supply board.
Replacement Parts To remove the front panel To remove the front panel 1 2 3 4 Remove the intensity knob by pulling it straight out. Disconnect the keyboard ribbon cable from the system board. Remove the External Trigger nut from the BNC (HP 54645A only). Use a screwdriver to release retainer tab A, and your finger to release retainer tab B. See the following figure.
Replacement Parts To remove the display To remove the display 1 Remove the front panel on the HP 54645A/D. 2 Disconnect the ribbon cable and the calibration cable from the display. 3 Using the T10 TORX driver, remove the two screws that hold the display to the deck. Make sure that when you re-install these screws that you use the correct parts. If longer screws are used, they can short the system board to ground. 4 As you lift the display, rotate it off the two tabs on the side of the deck.
Replacement Parts To remove the front-panel BNC connectors To remove the front-panel BNC connectors This procedure applies to channel 1 and 2 BNC connectors on HP 54645A, and to channel A1 and A2 BNC connectors on HP 54645D. 1 Remove the system board. 2 De-solder the center conductor wire and the probe readout wire from the board. 3 Using the T10 Torx driver, remove the screw holding the BNC to the housing.
Replacement Parts To remove the power supply To remove the power supply 1 Remove the fan. 2 Disconnect the ground wire (green wire with the yellow stripe) from the deck. 3 Disconnect the ribbon cable from the power supply board. 4 Use a screw driver to gently unhook the latch that holds the white shaft to the power switch, then disconnect the shaft from the power switch. After you disconnect the shaft, make sure you position it in the recess along the side of the display bracket.
Replacement Parts To remove the keyboard To remove the keyboard 1 Remove the front panel. 2 Remove all the knobs by pulling straight out. 3 Flex the bezel of the front panel to unsnap the small keyboard under the display opening. 4 Using the T10 TORX driver, remove the three screws from the large keyboard. Make sure that when you re-install these screws that you use the correct parts. If longer screws are used, they can damage the front-panel label.
Replacement Parts Replacing the Option 005 board Replacing the Option 005 board The Option 005 board is only serviceable at the board level. No component level information is available. WARNING CAUTION Hazardous voltages are on the CRT, power supply, and display sweep board. To avoid electrical shock, disconnect the power cord from the oscilloscope. Wait at least three minutes for the capacitors in the instrument to discharge before you begin disassembling the oscilloscope to remove Option 005.
Replaceable Parts The Hewlett-Packard exchange program allows you to exchange a faulty assembly with one that has been repaired and performance verified by Hewlett-Packard. The system board is part of this exchange program with Hewlett-Packard. After you receive the exchange assembly, return the defective assembly to Hewlett-Packard. • Customers in the United States have 30 days to return the defective assembly.
Replacement Parts To order a replacement part To order a replacement part • To order a part in the material list, quote the Hewlett-Packard part number, indicate the quantity desired, and address the order to your nearest Hewlett-Packard Sales Office. • To order a part not listed in the material list, include the model number and serial number of the oscilloscope, a description of the part (including its function), and the number of parts required.
Replacement Parts To order a replacement part Figure 8-3 Exploded View of HP 54645A/D Oscilloscope 8-13
Replacement Parts To order a replacement part Table 8-1 HP 54645A/D Oscilloscope Replaceable Parts Reference Designator A1 A2 A3 (HP 54645A) A3 (HP 54645A) A3 (HP 54645D) A3 (HP 54645D) A4 (HP 54645A) A4 (HP 54645D) HP Part Number 0950-2735 2090-0316 54645-66503 54645-69503 54645-66501 54645-69501 54600-66502 54645-66502 Qty Description 1 1 1 1 1 1 1 1 Power supply assembly Display assembly System board Exchange system board System board Exchange System board Keyboard Keyboard B1 3160-1006 1 Fan
Replacement Parts To order a replacement part Reference Designator HP Part Number Qty Description MP17 MP18 (HP 54645A) MP19 MP20 MP21 MP22 MP23 MP24 MP25 MP26 54630-94605 54645-42501 54630-61601 54630-61602 54645-27601 54645-09101 0380-0912 2190-0068 1250-2075 54601-04101 1 1 1 1 2 2 1 1 1 1 Rear-panel label External trigger nut Ribbon cable—display Ribbon cable—power supply BNC RFI spring Spacer Washer—calibrator output Nut—calibrator output Attenuator lid W1 W1 W1 W1 W1 8120-1521 8120-1703 8120
Replacement Parts To order a replacement part Figure 8-4 Exploded View of Option 005 and Related Oscilloscope Parts 8-16
Replacement Parts To order a replacement part Table 8-2 Option 005 Replaceable Parts Reference Designator HP Part Number Qty Description A3 A5 * 54602-66502 1 1 System Board (part of standard instrument) Video Trigger Board H2 H3 0515-0380 0515-0430 5 7 Machine screw M4 X 10 (part of standard instrument) Machine screw M3 X 6 (+2 screws for Option 005) MP6 MP11 54601-00101 54602-64402 1 1 MP30 54602-94305 1 Deck (part of standard instrument) Cabinet (comes with handle and feet installed –
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9 Performance Characteristics
Performance Characteristics This chapter lists the operating characteristics and performance specifications for both the HP 54645A and HP 54645D Oscilloscopes.
Performance Characteristics HP 54645A/D Oscilloscopes HP 54645A/D Oscilloscopes Number of Channels Probes Range Vernier calibrated Position (offset) range Dynamic Input Range DC Vertical Gain Accuracy 1, 2, 5 sequences Vernier DC Vertical Offset Accuracy serial prefix < US3707 serial prefix ≥ US3707 Single-Cursor Accuracy Dual-Cursor Accuracy Bandwidth (3dB) Repetitive Single shot Bandwidth limit Rise Time (calculated) Coupling AC Coupling Corner Frequency Input Impedance Maximum Input Probe ID (HP & Tek
Performance Characteristics HP 54645D Digital Channels HP 54645D Digital Channels Number of Channels Threshold Selections Maximum Input Voltage Threshold Range Threshold Accuracy1 Input Dynamic Range Minimum Input Voltage Overdrive Minimum Input Voltage Swing Input Capacitance Input Resistance Channel-to-Channel Skew Predefined Thresholds Cable Specifications 1 16 Digital—labeled D0-D15 D0-D7, D8-D15 ± 40 V peak ± 6.
Performance Characteristics HP 54645A/D Oscilloscope Digitizing System HP 54645A/D Oscilloscope Digitizing System Vertical Resolution Horizontal Resolution Sample Rate Sample Rate Accuracy Peak Detection Averages Memory Depth Data Throughput 8 bits on all settings except 7 bits on < 2 mV/div to 1 mV/div 500 (displayed points) 200 MSa/s maximum per channel 0.01% 5 ns digital 4, 8, 16, 32, 64, 128, 256, Smoothing—selectable 1 M maximum Up to 3.
Performance Characteristics HP 54645A/D Time Base HP 54645A/D Time Base Range 2 ns/div to 50 s/div (HP 54645A) 5 ns/div to 50 s/div (HP 54645D) Resolution 40 ps Vernier 1-2-5 increments when Off, 25 minor increments between major settings when On Reference Positions Left, Center, Right Random Repetitive Stop freezes display Pan and Zoom (Random Repetitive) Shows only 1 trigger Delay Range Pre-trigger (negative delay) Post-trigger (positive delay) 1 screen or 2.
Performance Characteristics HP 54645A/D Oscilloscope Trigger System HP 54645A/D Oscilloscope Trigger System Sources Range (Internal) Edges Sensitivity < 10 mV/div, DC to 25 MHz < 10 mV/div, 25 MHz to 100 MHz > 10 mV/div, DC to 25 MHz > 10 mV/div, 25 MHz to 100 MHz Coupling Maximum Input Range (External) Sensitivity Coupling Modes Holdoff Time Channels 1 and 2, line, and EXT (on HP 54645A only) ± 6 div Either rising or falling ≤ 1 div or 2 mV ≤ 1.5 div or 3 mV ≤ .35 div or 3.
Performance Characteristics HP 54645A Oscilloscope Trigger System HP 54645A Oscilloscope Trigger System Trigger System Glitch Triggering Minimum duration time Maximum duration time Source, Mode/Coupling, Slope/Glitch Holdoff, Level Channels 1 and 2, Line, EXT (no trigger out) Either rising or falling (not both) Enhanced TV/Video Trigger, Basic TV (Line, Field) < and > duration, in range, out of range, 8 ns 100 seconds HP 54645D Mixed-Signal Oscilloscope Trigger System Trigger System Edge Trigger Patte
Performance Characteristics HP 54645A/D Setup Functions HP 54645A/D Setup Functions Save/Recall 10 front-panel setups can be stored and recalled from non-volatile memory. Trace Memory Two volatile pixel memories allow storage of Autostore waveforms. Channel Labels (HP 54645D only) Each channel may be identified with a six-character label. Labels can be created from a front-panel label generator and a library of up to 75 preset and user-defined labels. Probe Calibrator Amplitude 5.0 V, Frequency ~1.
Performance Characteristics HP 54645A/D General Characteristics HP 54645A/D General Characteristics Environmental Characteristics Physical EMI Commercial EMI, Military 1 Meets the requirements of MIL-T-28800D for Type III, Class 3, Style D equipment as described here.
Performance Characteristics Option 005 General Performance Characteristics Option 005 General Performance Characteristics Video Standards NTSC, PAL, PAL-M, SECAM, Generic Video Trigger Modes: Line Field 1, Field 2, Alternate Fields All Lines Field 1 Defined as that field with the 3 lines of vertical sync starting at line 4. Is actually color field 1 or color field 3. Field 2 Defined as that field with the 3 lines of vertical sync starting at the midpoint of line 3.
9-12
10 Messages
Messages This chapter presents the various messages displayed by the instrument, explains what they mean, and gives instructions for corrective action if necessary. All messages in this chapter in presented in alphabetical order. Other messages may be self-explanatory There may be other messages that appear on the HP 54645A/D display that are self-explanatory, or clear enough that they are not described in this chapter.
Messages Messages Address Error A processing fault occurred during operation. Cycle power to the oscilloscope, or perform a hard reset by cycling power with the two rightmost softkeys depressed. If this does not correct the problem, contact your HP Sales Office for assistance. Are you REALLY Sure?? Overwrite ALL 75 labels, YES to proceed This message appears when you press Yes to confirm initialization of the label list. (HP 54645D only) • To initialize the label list, press the Yes softkey.
Messages Delay time = When the Horizontal Mode is Delayed, this message appears while you are adjusting the Delay knob, to inform you of the current delay time setting. Digital channels are not available in XY or Roll mode When setting the Horizontal Mode to XY or Roll, you cannot select digital channels D0-D15 on HP 54645D. Digital channels cannot be moved in XY or Roll mode When setting the Horizontal Mode to XY or Roll, you cannot change the position of channels D0-D15 on HP 54645D.
Messages Measurement already selected This message appears when you select a single-channel measurement that is already running. Note that measurement results for the selected measurement are displayed on the message line, but are temporarily overwritten by this message. No active signal was found: Please check connections This message appears when you select Autoscale, but the oscilloscope was unable to find an input signal on any channel at any threshold setting.
Messages Privilege Violation A processing fault occurred during operation. Cycle power to the oscilloscope, or perform a hard reset by cycling power with one of the softkeys depressed. If this does not correct the problem, contact your HP Sales Office. Scope self-test passed This message appears when one of the oscilloscope self-tests passes. The selected channel is not displayed: Please select another The channel you selected with the Select knob is off.
Messages The Label List has not been changed This message appears when you press the No softkey during any step of label list reinitialization. Initialization of the label list is canceled, and the top-level label list menu reappears. (HP 54645D only) The Printing is canceled This message appears when you press the Cancel Print softkey to stop printing. The printing is complete This message appears when the oscilloscope has finished copying the screen to the printer.
Messages Threshold is at limit The threshold setting is used by the HP 54645D oscilloscope digital channel input comparators to decide whether a signal is a logic high or logic low. The threshold must be set to a value between –6.00 V and +6.00 V inclusive. Time/Div is at limit The time per division must be set to a value between 50 s/div and 2 ns/div inclusive.
Glossary This glossary is organized into two parts: logic and scope terms. Logic terms apply only to the HP 54645D MSO (Mixed-Signal Oscilloscope), and scope terms apply to both the HP 54645A/D Oscilloscopes. HP 54645D Logic Terms Acquisition is the process by which the MSO collects data. The oscilloscope acquires data by sampling the voltage on each analog and digital input channel and comparing it to the trigger condition.
Glossary Entered trigger operator is used in the advanced pattern trigger. “Entered” means that the trigger qualifier is satisfied as soon as the input waveforms have transitioned from a state that does not match the pattern to a state that does match the pattern. Graticule refers to the hash marks on the display. These marks can be set to full, frame, or none. Labels are terms defined or chosen from a predefined list to associate input channels with their functions in the system under test.
Glossary Sweep speed (time base) is the amount of time per division on the display, and is shown on the status line. When you vary the Time/Div setting while running an acquisition, the sample period is also being adjusted. HP 54645A/D Oscilloscope Terms Thresholds define the voltage at which there is a change from low to high. Thresholds specified can be TTL, CMOS, or ECL, or variable from -6.0 V to +6.0 V.
Glossary Autostore records the result of every acquisition on the display in half-bright tone. When Autostore is on, the oscilloscope updates pixel (display) memory with new acquisitions, but does not erase the results of previous acquisitions. Auto trigger mode causes the oscilloscope to fill the pre-trigger buffer, then searches for the trigger event for a predetermined interval. If no trigger is found, the oscilloscope forces a trigger and displays the data as though the trigger had occurred.
Glossary Delayed a horizontal mode that gives an expanded view of the main sweep. Delayed sweep is the oscilloscope display function that magnifies the contents of sample memory. Use delayed sweep to zoom in on a portion of the waveform and pan and zoom through it to examine it in greater detail. Display allows selection of either normal, peak detect, or averaged display modes. It also allows selection of vectors on/off and provides grid choices. Display memory is also called pixel memory.
Glossary Glitch trigger mode is indicated by a positive or negative pulse on the status line. In glitch capture mode, the oscilloscope uses memory resources to record an event where at least two transitions occurred between sample periods. The oscilloscope can capture pulses as narrow as 3.5 ns and as long as the sample period—1 ns at any sweep speed. HF Reject (high-frequency reject) adds a low-pass filter with a 3 dB point at 50 kHz to the trigger path.
Glossary Noise Rej (noise reject) decreases the trigger sensitivity to reduce triggering on signal noise. Normal allows a waveform to be displayed if a trigger signal is present and the trigger conditions are met. If there is no trigger signal, the oscilloscope does not trigger and the display is not updated. Normal trigger mode causes the oscilloscope to begin filling the pretrigger buffer with data. When the buffer is full, the oscilloscope will begin searching for the trigger event.
Glossary Run acquires data and displays the most recent trace. bleshooting. These memories are non-volatile. Run indicator is displayed at the right end of the status line when the acquisition is running. Single (single shot) triggers once when the trigger conditions are met. The oscilloscope must be rearmed before the oscilloscope retriggers by pressing either the Run or Autostore front-panel keys. Sample period is the interval at which the input is sampled.
Glossary Softkeys set up various options for major functions. The softkeys change depending on the function you select. Some softkeys have an immediate action, and others allow you to scroll through a list of choices. Some softkeys are labeled with two choices below; the highlighted choice is currently active. When several softkeys are displayed with a labeled bar over them, they are either related, or the choices are mutually exclusive. Source allows you to select a trigger source.
Glossary Trigger mode can be set to Auto Level, Auto, or Normal. See “Normal trigger mode” or “Auto trigger mode.” TV allows access to the TV mode and polarity keys. Vernier is a softkey for both HP 54645A/D in the Main/Delayed and Analog channel menus that gives finer increments of the sweep speed and Volts/Div. Voltage allows access to the automatic voltage measurement keys. Volts/Div Changes the vertical scaling in a 1-2-5 step sequence from 2 mV to 5 V. Waveform parameters are measured using cursors.
Index A accessories optional, 1–7 supplied, 1–5 to 1–9 accuracy testing thresholds, 7–12 acquisition and channels off, 2–24 buffer, 2–28 indicator for, 2–13 to 2–14 setting up with Autoscale, 2–18 to 2–19 single, 4–33 starting, 2–28 stopping, 2–28 acquisition memory location of trigger event, 4–22 to 4–28 setting time reference in, 4–22 to 4–28 time base affects time to fill, 4–27 acquisition results save in trace memory, 4–45 acquisition system performance characteristics, 9–6 self-tests, 7–11 action to c
Index preset configuration, 4–48 selecting, 2–26 selecting for edge trigger, 3–16 selecting for pattern trigger, 3–17 test thresholds, 7–14 testing acquisition system, 7–11 testing threshold accuracy, 7–12 turning labels on or off, 4–53 turning on and off, 2–24 characteristics Option 005, 9–11 See performance characteristics probe input impedance, 4–39 to 4–42 checking package contents, 1–5 to 1–9 checklist for solving problems, 7–4 to 7–6 circuit ground connecting oscilloscope, 1–11 to 1–12 circuit signal
Index E ECL threshold, 4–51 to 4–52 Edge, 3–16 edge and pattern triggers combined, 3–22 edge qualifier in pattern trigger, 3–17 edge trigger, 3–16 applications of, 3–12 qualifying a pattern, 3–13 edges defining for trigger, 3–20 Edit Label softkey, 4–46 entered (pattern trigger), 3–13 Entry knob, 3–17 choosing edge trigger channel, 3–16 choosing labels from list, 4–54 to 4–55 equation for voltage behavior, 4–41 equipment for testing threshold accuracy, 7–12 set up to test threshold accuracy, 7–13 Erase, 4–
Index status, 2–13 to 2–14 initializing label list, 4–58 input setting signal thresholds, 4–51 signals setting threshold, 4–51 to 4–52 input channels performance characteristics, 9–3 input comparators, 4–51 to 4–52 interface modules documentation, 2–34 make trace memory non-volatile, 4–43 interface parameters, 2–34 interfaces message, 10–6 interlaced TV system, 6–6 internal trigger, 9–11 interval of auto trigger, 3–3 vertical, 6–8 K keyboard removing, 8–9 kit training, 1–7 L Label, 4–56 to 4–58 Label key,
Index non-volatile settings label list, 4–56 non-volatile setup memory, 4–44 NTSC, 6–4, 6–6, 6–10 to 6–11 O odd field, 6–10 to 6–11 On/Off "Off" channels, 2–24 measurements and channels, 2–24 operation of Autoscale, 2–20 operators for trigger, 3–19 to 3–24 Option 005, 6–2 characteristics, 9–11 triggering, 6–5 troubleshooting, 7–52 optional accessories, 1–7 order of channels, 2–26 ordering new assemblies, 8–11 to 8–17 oscilloscope, 1–2 accessories supplied with, 1–5 to 1–9 configuration preset, 4–48 to 4–50
Index sensing, 2–23 tip design, 4–40 probe cable, 1–11 to 1–12 probe calibrator performance characteristics, 9–9 probe leads removing from cable, 1–12 probes connect grabbers, 1–11 to 1–12 short together, 1–11 to 1–12 probing circuit under test practices, 4–42 problems obtain HP service, 7–4 solving, 7–3 trace display, 7–4 to 7–5 with channels, 7–5 to 7–6 procedures to test threshold accuracy, 7–12 to verify correct operation, 7–2 pulse measurements, 5–28 to 5–31 sync, 6–7 pulse parameters See time measure
Index On/Off, 2–24 Pattern, 3–17 software BenchLink for Microsoft Windows, 1–7 solutions to problems channels, 7–5 to 7–6 trace display, 7–4 to 7–5 solving problems See Service section Source softkey, 5–26, 5–29, 5–33 sources defining patterns and edges, 3–20 for trigger, 3–19 to 3–24 specifications performance, 9–2 threshold accuracy, 7–12 starting an acquisition, 2–28 state machine triggering on outputs, 3–23 status indicators, 2–13 to 2–14 status line, 2–32, 6–2 Stop, 2–28 Stop key, 4–38 stop printing,
Index trigger event position in acquisition memory, 4–22 to 4–28 trigger mode Auto, 2–13 to 2–14 Normal, 2–13 to 2–14 trigger not found and auto trigger, 3–3 trigger system Option 005 characteristics, 9–11 performance characteristics, 9–7 troubleshooting oscilloscope, 7–2, 7–17 TTL threshold, 4–51 to 4–52 turning channels on and off, 2–24 TV trigger, 5–18, 5–21, 6–12 trigger mode, 5–18 trigger-both fields, 5–21 vertical sync, 5–21 U undo Autoscale, 2–18 to 2–19, 4–48, 6–4 unexpected trace display, 7–5 unho
DECLARATION OF CONFORMITY according to ISO/IEC Guide 22 and EN 45014 Manufacturer’s Name: Hewlett-Packard Company Manufacturer’s Address: Colorado Springs Division 1900 Garden of the Gods Road Colorado Springs, CO 80907 USA declares, that the product Product Name: Digitizing Oscilloscope Model Number(s): HP 54645A/D Product Option(s): All conforms to the following Product Specifications: Safety: IEC 1010-1:1990+A1 / EN 61010-1:1993 UL 3111 CSA-C22.2 No. 1010.
Product Regulations Safety IEC 1010-1:1990+A1 / EN 61010-1:1993 UL 3111 CSA-C22.2 No.1010.1:1993 EMC This Product meets the requirement of the European Communities (EC) EMC Directive 89/336/EEC. Emissions EN55011/CISPR 11 (ISM, Group 1, Class A equipment) Immunity EN50082-1 IEC 555-2 IEC 555-3 IEC 801-2 (ESD) 4kV CD, 8kV AD IEC 801-3 (Rad.) 3 V/m IEC 801-4 (EFT) 0.5 kV, 1kV Sound Pressure Level Code1 Notes2 1 1 2 1 2 1 Performance Codes: 1 PASS - Normal operation, no effect.
© Copyright HewlettPackard Company 1996-1997 All Rights Reserved. Reproduction, adaptation, or translation without prior written permission is prohibited, except as allowed under the copyright laws. Microsoft is a registered trademark of Microsoft Corporation. Document Warranty The information contained in this document is subject to change without notice.
Product Warranty This Hewlett-Packard product has a warranty against defects in material and workmanship for a period of three years from date of shipment. During the warranty period, Hewlett-Packard Company will, at its option, either repair or replace products that prove to be defective. For warranty service or repair, this product must be returned to a service facility designated by Hewlett-Packard.
