Operating instructions

ManualsBrandsAeroflex ManualsComputer equipment2946A

Contains

Operating Manual

for

COMMUNICATIONS

SERVICE MONITOR

2945A

Part number 46882-311D

Issue 4

Creation date 11-Nov-99

Summary of content (237 pages)

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Contains Operating Manual for COMMUNICATIONS SERVICE MONITOR 2945A Part number 46882-311D Issue 4 Creation date 11-Nov-99
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COMMUNICATIONS SERVICE MONITOR 2945A  IFR Ltd. 1999 No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, or recorded by any information storage or retrieval system, without permission in writing by IFR Ltd. Printed in the UK Manual part no.
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About this manual This manual explains how to use the Communications Service Monitor 2945A. It applies to instruments fitted with main software version 4.xx and cellular software version 4.xx. Intended audience People who need to test mobile radio systems and associated equipment. Structure Chapter 1 General information and performance specification. Chapter 2 Gives installation instructions, including connection of peripheral equipment. Chapter 3 Operating instructions. Setting up and use.
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About this manual (continued) Associated publications (continued) Operating manual supplements provide operating details for specific system test software.
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Contents Precautions ........................................................................................................................................................v Chapter 1 GENERAL INFORMATION.................................................................................................. 1-1 Performance data ..................................................................................................................... 1-7 Chapter 2 INSTALLATION ........................................
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Precautions These terms have specific meanings in this manual: WARNING information to prevent personal injury. information to prevent damage to the equipment. important general information.
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PRECAUTIONS Fuses Note that the internal supply fuse is in series with the live conductor of the supply lead. If connection is made to a 2-pin unpolarized supply socket, it is possible for the fuse to become transposed to the neutral conductor, in which case, parts of the equipment could remain at supply potential even after the fuse has ruptured. WARNING Fire hazard Make sure that only fuses of the correct rating and type are used for replacement.
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OPERATING MANUAL 2945A Do not charge at an ambient temperature of greater than 40°C. Do not dispose of in a fire. Do not short circuit. Do not crush, puncture, open, dismantle or otherwise mechanically interfere with. Do not store at temperatures in excess of 60°C. Do observe the correct polarity and connect correctly. During normal service, small quantities of hydrogen and oxygen may be vented from the battery pack.
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Chapter 1 GENERAL INFORMATION Contents Purpose and features ...................................................................................................................... 1-2 Transmitter testing .................................................................................................................. 1-2 Receiver testing ...................................................................................................................... 1-3 Duplex testing...................................
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GENERAL INFORMATION Purpose and features 2945A is a portable Communications Service Monitor for carrying out production, routine and maintenance testing on radio transmitters, receivers and two way radio communication equipment.
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OPERATING MANUAL 2945A The AF generators, to provide a source of modulation for the transmitter under test. The RF power meter, to measure the mean output power level of the transmitter. The RF counter, to obtain the mean RF frequency of the transmitter output. The modulation meter, to measure the modulation depth or the deviation level and to provide a demodulated output signal. Single sideband transmissions can be demodulated when the SSB option is implemented.
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GENERAL INFORMATION During all of the above procedures, the RF levels, the distortion levels and modulation levels can be displayed on bar charts as well as being provided as a digital read-out. The AF waveforms can also be studied using the digital oscilloscope facility. Duplex testing Service Monitor MODULATED RF TEST SIGNAL RF SIGNAL FROM RADIO UNDER TEST DEMODULATED AF SIGNAL Rx/Tx Under Test AF GENERATOR OUTPUT C3242 Fig.
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OPERATING MANUAL 2945A Systems testing Cellular and trunked radio-telephone systems Service Monitor ! RF ! AF OUT AF IN + SERVICE CONNECTION DC SUPPLY C3253 Fig. 1-5 Cellular radio-telephone test setup With the appropriate cellular or trunked mobile telephone option included, the monitor has built-in software to generate and interrogate signals of the various cellular or trunked telephone systems. This gives the facility for testing all aspects of these systems.
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GENERAL INFORMATION AF testing Service Monitor AUDIO Amplifier Under Test AUDIO C3244 Fig. 1-6 AF test setup The AF testing mode allows the dual AF generators and the tones generator to be used as a signal source. The AF voltmeter, distortion meter, bar chart displays and the AF counter can all be used to provide data relating to signals applied to the AF input connector. The digital oscilloscope is also available for studying AF waveforms.
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OPERATING MANUAL 2945A Performance data Receiver measurements RF signal generator Frequency Range 400 kHz to 1.05 GHz Resolution 10 Hz Indication 10 digit display Setting Keyboard entry, delta increment / decrement function and rotary control Accuracy As frequency standard Output Level Range Rx Test: N-Type socket: −141 dBm to −21 dBm BNC socket: −115 dBm to +5 dBm. (usable to +7 dBm) Resolution 0.1 dB Indication 4 digits plus sign (dBm, dBµV, µV, mV, PD/EMF).
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GENERAL INFORMATION ±7% ±1 digit, for mod freq of 1 kHz, CW 1.5 MHz to 400 MHz. Accuracy ±10% ±1 digit for mod freq of 50 Hz to 5 kHz, CW 1.5 MHz to 400 MHz. ±15% ±1 digit, for mod freq of 50 Hz to 15 kHz, CW 1.5 MHz to 400 MHz.
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OPERATING MANUAL 2945A Audio Frequency Meter Frequency Range 20 Hz to 20 kHz Resolution 0.1 Hz, less than 10 kHz 1 Hz, at 10 kHz and above Indication 5 digits Accuracy As frequency standard ± 1 digit ± resolution Sensitivity 50 mV Audio SINAD Meter Frequency 1 kHz Range 0 to 18 dB and 0 to 50 dB Resolution 0.1 dB Indication 3 digits and barcharts Accuracy ± 1 dB Sensitivity 50 mV (100 mV for 40 dB SINAD).
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GENERAL INFORMATION Audio and Modulation Filters 300 Hz Lowpass 300 Hz Highpass 3 kHz Lowpass 300 Hz to 3.4 kHz Bandpass 15 kHz Lowpass 750 µs de-emphasis. (NOT available in Audio Mode) Transmitter measurements RF Frequency Meter Frequency Range 100 kHz to 1.05 GHz Resolution 1 Hz or 10 Hz, selectable Indication Up to 10 digits Accuracy As frequency standard ±resolution Acquisition Time Less than 1 second (manual). Typically 3 seconds (autotune), operates over 10 MHz - 1.
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OPERATING MANUAL 2945A Modulation Meter Sensitivity Autotuned: 5 mW (N-Type) 0.05 mW BNC (antenna port) Manual Tuned:−34 dBm(N-Type) −60 dBm BNC (antenna port) Audio filters 300 Hz Lowpass 300 Hz Highpass 3 kHz Lowpass 300 Hz to 3.4 kHz Bandpass 15 kHz Lowpass 750 µs de-emphasis Amplitude Modulation Frequency Range 100 kHz to 1.
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GENERAL INFORMATION Intermodulation Distortion Better than 70 dB for two signals at −30 dBm into first mixer Sweep speeds 10 ms/div minimum (Optimum sweep speed and bandwidth selected according to span) Update Rate Using “AUTO” resolution B/W selection SPAN Marker Indication RES B/W UPDATE 10 kHz 100 kHz 1 MHz 300 Hz 3 kHz 30 kHz 5 SWEEP/sec 9 SWEEP/sec 9 SWEEP/sec 10 MHz 100 MHz 1000 MHz 300 kHz 300 kHz 3 MHz 9 SWEEP/sec 5 SWEEP/sec 5 SWEEP/sec Single marker for frequency and level display
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OPERATING MANUAL 2945A User Defined Tones Up to two sequential tones frequency plans may be defined and stored within the Service Monitor. Any of the standard tone frequency plans may be copied to user defined and modified. Tone length 20 ms to 1 s. Standard tone frequencies may be selected from a menu. DTMF Generation and decoding of DTMF tones. DCS Generation and decoding of Digitally Coded Squelch, DCS. POCSAG Generation of POCSAG code CCIR No. 1 Rec 584. Bit rates from 400 to 4800 bit/s.
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GENERAL INFORMATION Safety This instrument is designed to comply with the requirements of EN61010-1 / IEC1010-1, for Class 1 Portable equipment and is for use in a pollution degree 2 environment. The equipment is designed to operate from an installation categories 1 or 2 supply.
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OPERATING MANUAL 2945A Printers supported 75,100,150 dots per inch laser printers FX80, FX100 Epson format. Accessory port Connector Outputs GPIB (Option 5) Capability 9 way female D-type. 4 independently programmable output lines, each one configurable as a logic line or as a relay contact closure. +5V supply available. For remote instrument control.
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GENERAL INFORMATION Optional Accessories 44991/145 43113/021 54431/023 Microphone with PTT Battery Pack 20 dB AF attenuator (BNC) 46884/728 54421/001 46662/571 46880/079 Rack Mounting Kit Antenna BNC Ever Ready Case Service Manual 54421/002 54421/003 54421/016 46884/789 54432/012 Directional Power Head 1 to 50 MHz Directional Power Head 50 to 1000 MHz 70 to 1000 MHz Lightweight Directional Power Head and Adaptor 400 to 1000 MHz Lightweight Directional Power Head and Adaptor Power Head Adaptor Wideba
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OPERATING MANUAL 2945A 46882-311D 1-17
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Chapter 2 INSTALLATION Contents Introduction.................................................................................................................................... 2-2 Initial visual inspection of new instruments................................................................................... 2-2 Ventilation ..................................................................................................................................... 2-2 ‘Ever-ready’ case shoulder strap................
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INSTALLATION Introduction This chapter deals with preparing the Service Monitor for use for the first time and with the checks to be made when the Service Monitor may have been used under unknown conditions. The latter situation could well apply where the Service Monitor is used by several users for differing tasks. Initial visual inspection of new instruments After unpacking the Service Monitor and before making any connections to a power source, inspect for any signs of mechanical damage.
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OPERATING MANUAL 2945A Bail arm option If the bail arm carrying handle is fitted, the Service Monitor will not fit into the optional Ever Ready Case, 46662/571. Do not attempt to attach the shoulder strap supplied with this Ever Ready Case to a Service Monitor fitted with a bail arm carrying handle. Power requirements The Service Monitor can be powered from a wide range of power sources, both AC and DC.
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INSTALLATION British Country IEC 320 plug type IFR part number United Kingdom Straight through 23422-001 United Kingdom Right angled 23422-002 The UK lead is fitted with an ASTA approved moulded plug to BS 1363. A replaceable 13 A fuse to BS 1362 is contained within the plug. This fuse is only designed to protect the lead assembly. Never use the plug with the detachable fuse cover omitted or if the cover is damaged.
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OPERATING MANUAL 2945A Hinweis: Dieser Schukostecker paßt nicht in die italienischen Standardsteckdosen nach CEI 23-16 Norm. Dieses Netzkabel sollte nicht in Dänemark verwendet werden, da hier keine Erdeverbindung hergestellt wird.
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INSTALLATION RF and AF connections All RF and AF connections should made using good quality connectors correctly fitted to appropriate cable. All connectors should be locked to the Service Monitor using the bayonet or threaded locking rings. Do not use leads that have damaged connectors or cable as this can cause poor performance and might damage the Service Monitor. RF leakage levels in a test set-up can be aggravated by the use of poor quality connector leads.
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OPERATING MANUAL 2945A 2 4 5 1 3 6 7 EARTH SHIELD C1785 Fig. 2-2 Accessory in/out socket pin numbers The socket is used for connecting dedicated accessories such as directional power heads and microphones with press to talk switching capabilities. Selection logic [or data signals] on pins 1,3 and 6 enables the Service Monitor to recognise the connections of an external accessory.
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INSTALLATION The pin connections are listed below and the pin locations shown in Fig. 2-3 RS232 serial port connections (as seen facing panel). Contact 1 2 3 4 5 Function Contact Not connected Rx data in Tx data out DTR Ground Function 6 7 8 9 1 DSR RTS CTS Not connected 5 C0783 6 9 Fig. 2-3 RS232 serial port connections (as seen facing panel) The use of a NULL MODEM cable assembly is required for connecting to control equipment such as PCs.
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OPERATING MANUAL 2945A Contact 1 2 3 4 5 6 7 8 9 10 11 12 Function Contact Data I/O 1 Data I/O 2 Data I/O 3 Data I/O 4 EOI DAV NRFD NDAC IFC SRQ ATN Ground shield Function 13 14 15 16 17 18 19 20 21 22 23 24 12 1 24 13 Data I/O 5 Data I/O 6 Data I/O 7 Data I/O 8 REN Pair with 6 Pair with 7 Pair with 8 Pair with 9 Pair with 10 Pair with 11 Logic ground C0683 Fig.
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INSTALLATION Test No 6 Transmitter Frequency. 10 MHz The above tests compare the generated power and frequency against the broadband power meter and the frequency meter at each of the frequencies specified. Related set-up. Manual tune The functions verified by the above tests are:Signal generator frequency and level accuracy. Power meter accuracy. Test No 7 to 14 Narrow band power meter. Power level +10 dBm. (Test No 7) to -60 dBm.
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OPERATING MANUAL 2945A Routine maintenance Ventilation fan and filter The ventilator fan on the rear of the Service Monitor is fitted with a filter to prevent the ingress of foreign matter into it. This should be inspected and cleaned at regular intervals. The procedure for this is as follows:Disconnect the Service Monitor from the mains supply and from any DC supply. Remove any other connections to the Service Monitor.
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INSTALLATION Check that the equipment has been installed in accordance with the instructions provided (e.g. that ventilation is adequate, supply isolators are accessible, supply wiring is adequate and properly routed). The condition of the mains supply lead and supply connector(s). Check that the mains supply switch isolates the Service Monitor from the supply. The correct rating and type of supply fuses. Security and condition of covers and handles. Check the supply indicator functions (if fitted).
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OPERATING MANUAL 2945A Cleaning Before commencing any cleaning, switch off the Service Monitor and disconnect it from the supply. The exterior surface of the case may be cleaned using a soft cloth moistened in water. Do not use aerosol or liquid solvent cleaners.
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Chapter 3 LOCAL OPERATION Contents About this chapter ....................................................................................................................3-4 Front panel layout.....................................................................................................................3-4 Rear panel controls and connectors ...........................................................................................3-8 Getting started ....................................................
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LOCAL OPERATION Contents (continued) Output level..................................................................................................................... 3-71 Tone selection.................................................................................................................. 3-71 Tone frequency shift ........................................................................................................ 3-71 DCS ......................................................................
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OPERATING MANUAL 2945A Fig. 3-11 Fig. 3-12 Fig. 3-13 Fig. 3-14 Fig. 3-15 Fig. 3-16 Fig. 3-17 Fig. 3-18 Fig. 3-19 Fig. 3-20 Fig. 3-21 Fig. 3-22 Fig. 3-23 Fig. 3-24 Fig. 3-25 Fig. 3-26 Fig. 3-27 Fig. 3-28 Fig. 3-29 46882-311D Spurious response ‘Image Frequency’ location.......................................................3-48 One port duplex test setup......................................................................................3-50 Alternative two port duplex setups..............................
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LOCAL OPERATION About this chapter This chapter deals with using the Communications Service Monitor as a ‘stand alone’ instrument. The front panel layout is described and a brief explanation of all controls and connections is given. The connectors and occasional controls on the rear panel are identified. An introduction to each of the test modes explains the principles behind tests that can be carried out and suggests some applications for the use of the monitor.
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OPERATING MANUAL 2945A The information display area, which shows the parameters relating to the test, together with settings and results, including bar charts. When the oscilloscope function is called up, all bar charts are removed from the display and the standard or expanded oscilloscope screen displayed. When the SPEC ANA test mode is selected, the display changes to the SPECTRUM ANALYZER screen. The test title area, where the current test description is displayed.
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LOCAL OPERATION Terminator keys used to conclude a parameter value are on the right of the group. They are coloured orange. When setting a modulation level, the entry is completed using the Hz, kHz, MHz or % key. The appropriate modulation type, FM or AM, is automatically selected. (4), (5) & (6) RF input and output connectors. The three sockets at the right hand edge of the front panel are the RF input/output connectors.
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OPERATING MANUAL 2945A undefined signal, or assessing the squelch operating level of a receiver. It has no mechanical stops. This control is also used to select items or digits from displayed lists, in conjunction with TONES and SYSTEM modes. (10) Audio connections. AF GEN OUT socket. The signal available at this BNC socket is the combined output from both or either of the AF generators and/or the tones generator. AF INPUT socket.
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LOCAL OPERATION Rear panel controls and connectors Fig. 3-3 Rear panel layout, (with optional GPIB fitted) On the rear panel of the instrument are: - 3-8 (20) AC power supply input connector. One range for all mains voltages. See the Performance data section in Chapter 1. The AC supply fuse is contained within this connector. (21) DC input voltage selector. Switches the power supply DC input circuits to match the available supply voltage. Ranges are 11-20 V and 18-32 V. (22) Power switch.
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OPERATING MANUAL 2945A (31) Serial port. The SERIAL PORT connector provides RS232 interface facilities for remote control. It is also used for the serial output to a printer. Connection details are given in Chapter 2, under Remote control connections, RS232. Getting started (Applying power and selecting test modes) The power ON/OFF switch, located on the rear of the instrument, has three positions. Pressing the inside toggle will power up the instrument, from either AC or DC supply.
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LOCAL OPERATION To move to the top level menu of any test mode, including the currently active mode, press the relevant ‘MODE’ key. For detailed use of specific TEST MODES see the section later in this chapter relating to that test mode. HELP/SETUP Pressing the [HELP/SETUP] key, at any time, will display the screen shown in fold out diagram (1-0), or a variation of it. Displaying the HE LP/SETUP screen does not interrupt any ongoing operation or test.
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OPERATING MANUAL 2945A Setup page 1 This page allows the following optional settings to be selected. RF Counter Resolution 1 Hz/10 Hz The RF counter resolution can be set to 1 Hz or 10 Hz. Selecting 1 Hz will slow the screen update rate by a factor of 10:1. The choice is made by toggling between the two options using the soft key adjacent to the text.
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LOCAL OPERATION Setup page 2 This page allows the following optional settings to be selected. Audio Level Measured in: Repeated presses of the adjacent soft key will toggle through Volts, dBm, dBV or Watts and highlight the selection in inverse video. The level of a signal applied to the AF input socket is measured in terms of the selected option. This will then apply to all subsequent measurements. The indicated output level from the AF generators is not affected by this selection.
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OPERATING MANUAL 2945A Power Up From Successive presses of this key will toggle through the options available for configuration of the Service Monitor at ‘Power Up’. Last Used Store 0 Store 0 is loaded with the current settings each time power is removed from the instrument. With this selection made, the instrument will power up to the same settings as when power was removed, whether this was by user action or through power failure. Preset Store 1 Store 1 contains the factory preset settings.
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LOCAL OPERATION Spectrum analyzer The spectrum analyzer (SPEC ANA) mode presents a graphical display of Radio Frequency against RF level over a selected sweep of the RF spectrum. Data relating to the setup and to measurements of the signals being analyzed is presented on the periphery of the display. As well as the basic spectrum analyzer function, the monitor has a ‘Look and Listen’ function which allows the operator to listen to the demodulated signal extracted from the RF signal being examined.
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OPERATING MANUAL 2945A Using the test modes Brief descriptions As the Service Monitor 2945A is a duplex instrument, the RF signal generator and the receiver circuits are able to operate simultaneously. This allows mobile transceivers to be tested under their normal operating conditions, with both their receiver section and transmitter section functioning. By selecting a particular test mode on the Service Monitor, one or both sections of the transceiver can be studied.
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LOCAL OPERATION AF TEST With AF TEST selected, the AUDIO TEST screen is displayed and access to the AF TEST features is available. See fold out diagram (7-0) at the end of this chapter. The RF generator is disabled. SYSTEMS The SYSTEM key gives access to the SYSTEM TEST mode. If any of the system test options have been provided on the particular Service Monitor, the user is able to carry out automatic and/or manual tests to pertinent equipment.
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OPERATING MANUAL 2945A Tx test (transmitter testing) Overview The Communications Service Monitor 2945A has been designed to test the performance of mobile communication equipment. This section explains the use of the Tx TEST mode. Typical uses are:• Performance checking following manufacture • Routine quality assurance testing • Workshop or field fault diagnosis etc.
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LOCAL OPERATION Connections AF VOLTMETER AF GEN 1 RF POWERMETER DISTORTION METER 20dB ATTENUATOR AF GEN 2 MODULATION METER AF FILTERS AF COUNTER TONES GEN RF COUNTER AF OSCILLOSCOPE SERVICE MONITOR AUDIO AMPLIFIER RF IN AF GEN OUT 'N' ANTENNA ALTERNATIVE CONNECTIONS Tx UNDER TEST C3373 Fig. 3-4 Transmitter test connections The transmitter and the Service Monitor are connected as shown in Fig. 3- 4, Transmitter test connections.
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OPERATING MANUAL 2945A The Audio frequency input connection to the transmitter must be to the audio input, in place of the usual microphone input. This connection will vary for differing types of equipment. Points to note are:• The microphone must be disconnected, as any input from it would affect the performance of the test. • The microphone and its cable may complete the ‘keying’ circuit of the transmitter using a ‘press to talk’ switch, in which case an alternative arrangement must be provided.
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LOCAL OPERATION Manual frequency setting Range; 100 kHz to 1.05 GHz 2 $0#/ legend highlighted, data can be entered from the keyboard to the Tx FREQ With the parameter. As the entry can only be a frequency setting, it is not necessary to select the orange [FREQ] key. Enter the required frequency by using the digit keys and the decimal point key if relevant.
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OPERATING MANUAL 2945A Directional Power The [Dir Power] key displays the screen required for using the optional directional power and VSWR accessories. The use of the Directional Power Head accessory is described in Appendix A of this manual, and of the Light-weight Directional Power Head accessory, in Appendix B. To leave this screen, press any of the blue MODE keys. The top level screen of that mode will be displayed.
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LOCAL OPERATION When ‘SSB’ demodulation has been selected, the RF sensitivity of the Service Monitor can be controlled manually. Three sensitivity settings are given as soft key choices; high, medium and low.
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OPERATING MANUAL 2945A Audio distortion measurement The Service Monitor is able to measure signal noise and distortion against the following parameters:Signal to noise ratio SINAD level Percentage distortion Press the [Dist S/N] key. The right hand soft keys change, to allow selection of S/N, SINAD and distortion measurements. Off Disables any active distortion measuring function. Hint.
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LOCAL OPERATION More (de-emphasis, FM deviation pk/rms, modulation dBr) Press the [More] key. The right hand soft keys change, to allow selection of de-emphasis mode, and FM deviation and modulation measurement modes. De-emph De-emphasis filtering, ON/OFF, is toggled by alternate presses of the [Deemph] key. The de-emphasis filtering uses a 750 µs time constant to give a 6 dB/octave roll-off. De-emph ON appears on the main display when appropriate.
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OPERATING MANUAL 2945A shape settings of their last use in the Rx TEST mode will be retained within the Rx TEST mode setup. These settings will be effective when the generators are switched to the ‘ON’ condition in receiver test mode. Their use as audio generators in the Tx TEST mode will then be disabled. Pressing the [Lock] key locks the output level of the two audio generators to the same level. The unselected generator locks to the level of the selected generator.
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LOCAL OPERATION WARNING Hot surfaces Take care when touching the RF Input Type N connector after the application of high levels of continuous power. If 50 W is applied for a prolonged period, the temperature of the connector can become excessive. With the monitor in the Tx TEST mode, and the transmitter connected to the monitor as described above, key up the transmitter. The RF power bar chart gives an analogue representation of the active power meter reading.
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OPERATING MANUAL 2945A The harmonic number and frequency is shown over each active bar chart, with the level, in dBc, given as a digital read-out. The level of a harmonic which has a frequency above the RF range of the monitor cannot be measured and bar charts which would be given to these frequencies remain inactive. IF passband filters When making harmonic analysis readings, the IF passband of the Service Monitor can be set independently to that set in the main Tx TEST mode.
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LOCAL OPERATION To observe the power level profile of an RF signal during a level transition, the signal is applied to the RF input of the monitor and the instrument armed to trigger when a specific RF level is passed through. The instrument then displays an RF Power Level vs Time graph, showing the transition. Bandwidth The IF filter selected on the Tx TEST screen remains selected when the function is selected.
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OPERATING MANUAL 2945A trigger point centre screen with pre-trigger levels shown to the left and post-trigger levels shown to the right while 100 % will cause the display to finish (on the right of the screen) at the time of trigger. 25 % and 75 % will produce displays with these proportions of pre-trigger visible. The trigger point is indicated on the display by a medium pecked line.
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LOCAL OPERATION Fig. 3-7 Transient Analysis displays From this condition a permanent record can be made on a suitable printer by using the [DISPLAY HOLD], [Print], key sequence or stored to a memory card using the [DISPLAY HOLD], [Store], [Store Screen], key sequence. phase can be reset by pressing the When the current display is no longer required, the [arm] key.
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OPERATING MANUAL 2945A External attenuators Compensation for an external attenuator or test fixture included in the RF input path of the monitor can be programmed. The value, in dBs, of the attenuator should be entered in the RF Power Ext Atten: field of setup page 1. The value of the attenuator will then be included in power calculations and the power indicated by the power meter will be that at the input to the external attenuator. This feature makes use of the extended ranges of the power meter.
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LOCAL OPERATION Modulation characteristics Modulation frequency response and Companding/limiting The requirements of individual users will vary but the principle of the tests will be the same. A signal having a known level and frequency is applied to the AF input of the transmitter and the level of modulation produced is measured. To test the modulation characteristics of a transmitter with any degree of accuracy requires that the signal used to provide the modulation is accurately defined.
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OPERATING MANUAL 2945A *DUPLEX* All of the above information relating to modulation characteristics and frequency response testing also applies to tests made using the Dx TEST mode. The oscilloscope facility is not available when in Dx TEST mode. Modulation distortion dB dB Distortion Products Signal Filter Response Noise 1 a kHz Frequency 1 b dB Frequency kHz dB Filter Response Distortion Products Noise 1 c Frequency Noise kHz 1 d Frequency kHz C1640 Fig.
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LOCAL OPERATION The SINAD level is then calculated according to the formula:SINAD = 20 log = 20 log V1 dB V2 ( S + N + D) dB ( N + D) To obtain the distortion factor of a signal at the output of a transmitter the output level is measured and noted as for SINAD level measurement. A notch filter as used for SINAD measurement is used to make a second reading which comprises the same values as for the second SINAD measurement.
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OPERATING MANUAL 2945A The input signal level influences the readings obtained by the distortion measuring system and is usually specified as part of the test specification. *OSCILLOSCOPE* With the oscilloscope facility selected, the distortion level bar chart is removed from the display but the digital read-out is retained. *DUPLEX* When in the Dx TEST mode, modulation distortion tests are not displayed.
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LOCAL OPERATION Rx test (receiver testing) Overview The Communications Service Monitor 2945A has been designed to test the performance of mobile communication equipment. This section explains the use of the Rx TEST mode. Typical uses are:• Performance checking following manufacture • Routine quality assurance testing • Workshop or field fault diagnosis etc.
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OPERATING MANUAL 2945A Connections MOD GEN 1 AF VOLTMETER AF FILTERS MOD GEN 2 DISTORTION METER RF GENERATOR 20dB ATTENUATOR AF COUNTER TONES GEN AF OSCILLOSCOPE RF OUT SERVICE MONITOR BNC 'N' AF IN ALTERNATIVE CONNECTIONS RF IN AF OUT Rx UNDER TEST C3374 Fig. 3-9 Receiver test connections Before making any connections between the Service Monitor and the receiver ensure that the RF generator of the Service Monitor is OFF. With the Rx TEST mode selected, press [RF Gen] key legend.
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LOCAL OPERATION The receiver and the Service Monitor should be connected as shown in Fig. 3- 9 Receiver test connections. The block diagram of the Service Monitor shows the signal routeing within it. Points to note are:The power source for the receiver should be reliable and stable. The battery of a vehicle may discharge if supplying a mobile transceiver during prolonged testing or the earth connection may become open circuit if the transceiver is removed from its normal location.
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OPERATING MANUAL 2945A Output level setting Range N-Type connector, -135 dBm to -15 dBm; 0.04 mV to 40 mV pd BNC connector, -115 dBm to +5 dBm; 0.4 mV to 400 mV pd (with uncalibrated overrange to +7 dBm) WARNING Hot surfaces Take care when touching the RF Input Type N connector after the application of high levels of continuous power. If 50 W is applied for a prolonged period, the temperature of the connector can become excessive. The signal generator output level is set using the data keys.
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LOCAL OPERATION Modulation frequency and level The frequency range and level must not exceed the following limits:Modulating freq. range 20 Hz to 20 kHz. AM depth range 0 to 99% total sum of active modulation sources. FM deviation range 0 to 75 kHz total sum of active modulation sources. To enable or set up the modulation generators press the [Mod Gen] key. The screen and menu shown in fold out diagram (4-2) will be displayed.
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OPERATING MANUAL 2945A External Modulation An external modulation source may be used to modulate the RF generator signal. Pressing the [Ext Mod] key will display the external modulation input selection menu. The options available are:[DC Ext] Selects the ‘EXT MOD IN’ connector on the rear of the instrument, with DC coupling. [AC Ext] Selects the ‘EXT MOD IN’ connector on the rear of the instrument, with AC coupling .
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LOCAL OPERATION that of the input to the Service Monitor. With the input impedance set at High, the indicated level is that of the input to the Service Monitor with an assumed 600 Ω load. AF filters The AF signal to the AF INPUT connector on the front panel can be filtered using the following audio filters:0.3 - 3.4 kHz band pass † ‡ 50 kHz low pass 15 kHz low pass 300 Hz low pass CCITT† or C-MESS‡ Only if option 23 (CCITT filter) is fitted. Only if option 24 (C-MESS filter) is fitted.
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OPERATING MANUAL 2945A See Fig. 3-8 a, & d, Distortion level and signal to noise level measurements , on page 3-33. The distortion bar chart is graduated in dB and is also displayed as a digital read -out above the bar chart. The Rx test menu is recalled automatically after pressing this key. SINAD Selects SINAD as the measurement method. The modulation generator is set to 1 kHz.
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LOCAL OPERATION As there is no direct/linear relationship between RF signal level and audio output with FM receivers, most manufacturers normally quote receiver sensitivity in one of the following four ways:12 dB SINAD sensitivity. 20 dB weighted SINAD sensitivity. 20 dB signal to noise sensitivity. 20 dB quieting sensitivity. When defined as part of a specification, the sensitivity will be given in the form:‘Sensitivity (12 dB SINAD) 0.25 µV’ or ‘Sensitivity (20 dB SINAD) 1.
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OPERATING MANUAL 2945A 20 dB signal to noise sensitivity This test determines the level of RF carrier which, when unmodulated will produce an AF output level due only to receiver noise, 20 dB below the AF level produced when modulated at the specified level and at the specified frequency. As the RF signal level is reduced, the ‘noise’ component of the AF signal will become proportionally greater. This will result in the Signal to Noise dB reading becoming closer to zero.
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LOCAL OPERATION Return to the RECEIVER TEST screen and adjust the RF output level to that required by the test specification. Switch the RF generator output ON by pressing the orange [ON OFF] function key. The audio output from the receiver is measured and the level and frequency displayed.
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OPERATING MANUAL 2945A Selectivity 2041 Signal Generator 'ADJACENT CHANNEL' SIGNAL Coupler Service Monitor 'ON CHANNEL' SIGNAL DE MODULATED AF TEST SIGNAL Rx Under Test C3375 Fig. 3-10 Selectivity test setup Selectivity tests are measurements of the capability of a receiver to differentiate between a wanted signal and an unwanted signal, usually that transmitted on an adjacent channel.
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LOCAL OPERATION In the example above, with a ‘wanted’ signal level of −90 dB and a ‘adjacent’ signal level of −7 dB, the performance of the receiver would be satisfactory. If the ‘adjacent’ signal level was found to read −13 dB the performance of the receiver would be below specification.
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OPERATING MANUAL 2945A difference in the level of the RF generator readings for the two frequencies, expressed in dB, is the ‘image frequency rejection ratio’. The procedure for measuring the IF rejection ratio is similar to that used to measure image frequency rejection and uses the same setup. The RF reference level is found at the RF frequency to which the receiver is tuned, then the RF generator is retuned to the IF frequency of the receiver under test.
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LOCAL OPERATION Dx test (duplex testing) TONES GEN RF GEN. ➤ ➤ MOD METER POWER METER MOD GEN 1 RF COUNTER AF COUNTER AF FILTERS DISTORTION METER SERVICE MONITOR MOD GEN 2 BNC RF OUT AF OUT AF VOLTMETER 20dB ATTEN. ANTENNA 'N' RF IN RF IN/OUT AF IN AF IN AF OUT TRANSCEIVER UNDER TEST C3376 Fig. 3-12 One port duplex test setup Overview With the Dx TEST mode selected, the screen and menu shown in fold out diagram (4 -0) is displayed.
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OPERATING MANUAL 2945A RF GEN. ➤ ➤ TONES GEN MOD METER POWER METER MOD GEN 1 RF COUNTER AF COUNTER AF FILTERS DISTORTION METER SERVICE MONITOR MOD GEN 2 AF VOLTMETER 20dB ATTEN. AF OUT BNC RF OUT 'N' RF OUT ANTENNA RF IN AF IN RF IN AF OUT AF IN TRANSCEIVER UNDER TEST ➤ ➤ ➤ ➤ SERVICE MONITOR SERVICE MONITOR 20dB ATTEN. RF BNC OUT 20dB ATTEN. RF 'N' IN RF OUT ANTENNA RF IN RF BNC OUT RF OUT 'N' RF IN ANTENNA RF IN C3377 Fig.
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LOCAL OPERATION Spectrum analyzer See Fig. 3-14, Spectrum analyzer test setup, and Fig. 3-15, Spectrum analyzer test setup using the tracking generator. LOCAL OSCILLATOR SERVICE MONITOR 20dB ATTEN. INPUT/ OUTPUT SWITCHING 'N' TYPE RECEIVER CIRCUIT SWEEP GENERATOR RF DETECTOR LOG. AMPLIFIER OSCILLOSCOPE ANTENNA RF OUT RF GENERATOR UNDER TEST C3378 Fig. 3-14 Spectrum analyzer test setup SERVICE MONITOR LOCAL OSCILLATOR OFFSET CONTROL TRACKING GEN. 20dB ATTEN.
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OPERATING MANUAL 2945A The level of RF signal present at the active RF input connector is measured at regular points along the sweep and plotted progressively across the display, thus building up a graph of RF level against frequency. The uses to which this facility can be put are varied. Within the radio communication field these can include examining the output of a transmitter for spurious radiations, for sideband response or noise levels.
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LOCAL OPERATION Start frequency Pressing the [Start Freq] key allows the required start point to be entered using the data entry keys. legend is highlighted. The variable control is active when the 1 Note that when using the variable control the span of the display remains constant. Therefore the stop frequency will follow any change to the start frequency. This is not the case when entering a start frequency by using the data keys.
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OPERATING MANUAL 2945A (6-2) to be displayed. Repeated presses of the [10 dB/2 dB] key will toggle the options, with the current choice being shown in the display. Ö × The LEVEL [ ] and [ ] keys adjust the reference level in either 2 dB or 10 dB steps, depending on the setting of the reference level vertical range. Video filter A video bandwidth filter can be switched into the display path to reduce the visible noise. To set the state of this, first press the [Vert Scale] key.
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LOCAL OPERATION The frequency response of any circuit connected between the tracking generator output and the spectrum analyzer input will be displayed. When making calculations relating to frequency response results, take into account the impedance matching between the circuit and the Service Monitor. (See performance specification.) The frequency offset facility adds to the above capability by allowing tests to be made to frequency shifting circuits.
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OPERATING MANUAL 2945A Look and Listen LOCAL OSCILLATOR ! I/O SWITCHING RECEIVER CIRCUITS SWEEP GEN. RF DET. LOG. AMP. AM/FM DEMOD AUDIO AMP. OSCILLOSCOPE ! 20 dB ATTEN. B1417 Fig. 3-16 Spectrum Analyzer setup, Look and Listen function The Look and Listen facility allows the instrument to be used for ‘OFF-AIR’ monitoring of transmissions while examining the area of radio spectrum on which the transmission being monitored is centred.
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LOCAL OPERATION The Span setting controls the sweep range covered by the spectrum analyzer. When in the Look and Listen mode the sweep span is selected from the Span menu accessible by pressing the [Span] key. Four span widths are available as listed below. 1 MHz 500 kHz 200 kHz 100 kHz Demod settings The ‘listen’ demodulator and its associated circuits are set to extract the information from the signal tuned to the centre frequency of the display.
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OPERATING MANUAL 2945A When operating in the Look and Listen mode, some functions or options of SPEC ANA mode will be available to the user. Reference to these is made on the display but their condition cannot be changed without returning to the main spectrum analyzer display.
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LOCAL OPERATION To enter the AF TEST mode press the blue [AF TEST] key. This will cause the screen and menu shown in fold out diagram (7-0) to be displayed. When the AF TEST mode is selected, the combined output from the AF generators, plus the data generator facility, is available at the AF output connector. Signals fed to the AF input connector are routed to the AF signal analysing circuits. See Fig. 3- 17, Audio test setup.
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OPERATING MANUAL 2945A Input filtering The AF signal to the AF INPUT connector on the front panel can be filtered using the following audio filters:0.3 - 3.4 kHz band pass † ‡ 50 kHz low pass 15 kHz low pass 300 Hz low pass CCITT† or C-MESS‡ Only if option 23 (CCITT filter) is fitted. Only if option 24 (C-MESS filter) is fitted. Press the [AF Filter] key. The right hand soft keys change, to allow selection of AF filters as shown above. Press the [Return] key after selecting the required filter.
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LOCAL OPERATION The monitor software calculates the SINAD level according to the formula:SINAD = 20 log = 20 log V1 dB V2 ( S + N + D) dB ( N + D) The distortion bar chart ranges available are 0 to 18 dB and 0 to 50 dB. The SINAD level is displayed as a digital readout above the bar chart. The AF test menu is recalled automatically after pressing this key. Dist’n Selects distortion percentage as the measurement method.
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OPERATING MANUAL 2945A Parameter Test mode Tx frequency Tx test mode AF generator 1 frequency AF generator 2 frequency Tx test mode Tx test mode AF generator 1 level AF generator 2 level Tx test mode Tx test mode RF generator frequency † RF generator level Rx test mode Rx test mode Modulation generator 1 frequency Modulation generator 2 frequency Rx test mode Rx test mode Modulation generator 1 level Modulation generator 2 level Rx test mode Rx test mode AF generator 1 frequency AF generator
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LOCAL OPERATION adjusted by use of the variable control (or the data entry keys) to 1,495 Hz, the next incremental step down will produce a frequency of 995 Hz. The assignment and value of a incremental setting will be retained, with the mode setup, when a different mode is selected or the instrument is powered down. This is of particular note when assigned to the AF generators as they are also the modulation generators within the Rx TEST mode and the AF generators within the AF TEST mode.
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OPERATING MANUAL 2945A Observing tones signals in other test modes The effect of any tones signalling on transmitters or receivers under test can be studied using any test mode of the Service Monitor. When a test mode is selected, (either by pressing the [Tx TEST] key, [Rx TEST] key etc. or by pressing the [Return] key), while any tones signal is running continuously (CTCSS or DCS Tones On; Sequential or DTMF continuous mode Sending), the tones will continue to be generated.
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LOCAL OPERATION When using the AF INPUT connector for TONES operation, the [ ] and [ ] keys on the TONES selection screen set the AF input sensitivity. The column headed Audio, in the above table, lists the AF input settings. The AF input signal level should be less than that shown for the current setting. Sequential tones Overview Sequential tones signalling systems use sequences of audio tones to control various functions of a radio system.
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OPERATING MANUAL 2945A Fig. 3-19 RF Sequential tones encoder display, main menu Setting the Tones mode The display is divided into three areas. • At the bottom of the display is a table listing the frequencies allocated to the 15 tones, 0 to E. Above the table is shown the system type, i.e. CCIR, ZVEI etc. • At the top of the display is a panel in which the tone sequence to be transmitted is assembled or edited. • The centre of the display shows information relating to the parameters of the system.
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LOCAL OPERATION Creating the tone sequence To create the required tone sequence, first press the [Enter Sequ] key to display the cursor in the tone sequence panel. Enter the required sequence by using any of the data entry keys 1 to 9, zero and the Hex digits A to E. The [Extend Tone] key is used to convert a standard tone to an extended tone or an extended tone to a standard tone.
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OPERATING MANUAL 2945A *-"B $0#/ of the orange [ON/OFF] function key. If is selected, the tones are still controlled by the orange [ON/OFF] function key, but if a frequency is entered using the data keys or if the variable control is adjusted, the tones will cease. They can then be re-started only when the RF SEQUENTIAL ENCODER screen or the AF SEQUENTIAL ENCODER screen is displayed. If the tones out routeing has been set to give AF tones, this is provided by audio generator 1.
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LOCAL OPERATION Revertive tones Revertive tones signalling takes various forms. The common factor is that a tone sequence received by a mobile transceiver or other receiver, will trigger a second sequence to be returned. The second sequence may be a duplicate of the first or a different sequence. It can be used to modulate a signal on a reverse channel or on a different channel. For some applications either or both of the tone sequences may be used as an AF signal.
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OPERATING MANUAL 2945A Output level The required output level of the tone signal can be set using the data entry keys, after highlighting the legend 2 + F by pressing the [Tone Level] key. The units used to specify the output level will relate to the selected output routeing and, when RF output is selected, the modulation method. The modulation type is automatically set, to be appropriate to the level terminator key used (FM for Hz, kHz or MHz; AM for %).
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LOCAL OPERATION The coded signal consists of a repeating 23 bit word which has error correcting information and timing using 14 bits, leaving nine bits available to carry address code. The digital signal is formatted as a simple non-return to zero (NRZ) signal which is used to directly modulate the transmitter. On frequency shift modulating systems a ‘1’ is usually made to increase the carrier frequency and a ‘0’ to decrease the carrier frequency.
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OPERATING MANUAL 2945A Return to the Rx TEST mode and check that the RF generator is active, then return to the TONES, DCS mode. The DCS coded signal will be produced when the legend Tone On is displayed against Tone Generate Mode:. See Tone ON/OFF control below. Tone ON/OFF control When the RF DCS ENCODER screen or the AF DCS ENCODER screen is displayed, the tone is turned on or off by the orange [ON/OFF] function key.
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LOCAL OPERATION Tx test DTMF tones function 0$ In the Tx TEST mode, with [Tones In] set to , DTMF tones generated within the mobile under test, are recovered from the RF signal and routed to the DTMF decoder. The RF frequency and modulation type of the transmitter under test is set up from the Tx TEST mode. Pressing the [Tones] key will display the screen shown in fold out diagram (2-5). The [DTMF] key will then give access to the RF DTMF DECODER screen shown in Fig.
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OPERATING MANUAL 2945A Press the [Tones] key to display the screen shown in fold out diagram (3-5). The [DTMF] key will then give access to the RF DTMF ENCODER screen. Formatting a tone sequence To create the required tone sequence, first press the [Enter Sequ] key to display the cursor in the tone sequence panel. If the tone sequence panel is not empty use the [DELETE] key to clear the sequence. Enter the required sequence by using any of the 16 available characters of the DTMF keypad.
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LOCAL OPERATION [Single Tone] After pressing this key, pressing any data entry key will cause the corresponding tone to be generated for the duration specified. Using the appropriate keys to send the selected tones to the receiver, tests can be made to the DTMF decoder. Dx test DTMF tones function When in Dx test mode the DTMF tones function can be accessed by pressing the [Tones] key. The user can select encode or decode.
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OPERATING MANUAL 2945A The POCSAG test facility within the Service Monitor generates a paging signal containing all elements of a ‘live’ signal. This signal is transmitted using the RF generator output to feed a suitable test rig or TEM cell. The decoder test facility allows a POCSAG type encoded signal to be decoded and displayed. To access the POCSAG test facility use the following key sequence:[Rx TEST], [Tones], [POCSAG]. The screen and menu shown in Fig.
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LOCAL OPERATION Table showing one possible arrangement of responses to differing function bit combinations Function Bit Combination Following Message Type Alerting Tones (00) (01) (10) (11) Numeric-only No message No message Alpha-numeric 1 beep 2 beeps 3 beeps 1 beep Level Alert type Select mess Address/Alert Type messages are selected by repeatedly pressing the Alert type key C1883 Fig.
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OPERATING MANUAL 2945A • Set the RIC (Radio Identification Code), to match that of the pager. Press the [RIC] key to on the display and enter the required number using the data entry highlight the legend keys, followed by [ENTER]. An attempt to enter a number which exceeds the range of the will be retained. system maximum will not be accepted and the previously displayed 0'!F 0'! The Service Monitor is now configured to produce a signal compatible with the radio pager.
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LOCAL OPERATION • On sequence 12345 to respond to, and display, the first incoming POCSAG format message which contains the numeric sequence ’12345’. Press the [Clear Sequ] key to remove any data from the decode register and to re-arm the decode function. The next message received, if it conforms to the set decode format, will be decoded and the message displayed. The following parameters of the signal are decoded and shown on the display:Bit Rate: The bit rate of the received signal.
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OPERATING MANUAL 2945A The soft keys have the following functions, (top to bottom):- ] [ ] [ ] [ ] Increases Y Sensitivity by one range per key press. [ Decreases Y Sensitivity by one range per key press. Increases Time/Division by one range per key press. Decreases Time/Division by one range per key press. [Scope/Bar] Steps to Expanded display or Bar chart display [Return] Returns display and menu to Tx TEST, Rx TEST or AF Test.
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LOCAL OPERATION Stores, settings/results Overview A section of the non-volatile RAM in the Service Monitor is designated as a user store for instrument settings and results. ’Power Down’ and ’Factory Pre-set’ settings are also held in this area of memory. The memory card option extends the ’User store’ facility, by providing additional memory and by allowing screen bitmaps, ’SYSTEM’ settings, ’SYSTEM’ results and ’SYSTEM User Defined’ test programs to be stored.
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OPERATING MANUAL 2945A Recalling Results When ’Results’ are recalled, the RESULTS SCREEN is displayed. The test results are shown against each of the parameter headings. Results of tests made when in the Dx TEST mode are shown with the RECEIVER TEST results in the top half of the display and the TRANSMITTER TEST results in the bottom half.
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LOCAL OPERATION Deleting store contents To delete the contents of an unprotected store location, proceed as follows:Press the [Delete] key. The inverse video message, ’Delete Store No.’ will be displayed. Key in the two digit address of the location to be deleted, using the data entry keys. The contents will be deleted as soon as the second digit is keyed and the location address list will show the location as ’Empty’. Once deleted, the contents cannot be retrieved.
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OPERATING MANUAL 2945A If a memory card is inserted that has not been formatted to the required standard, the message ’Card Not Formatted’ is displayed on the MEMORY CARD FORMAT screen. To apply formatting, press the [Format Card] key. The message ’Writing To Mem Card. Do Not Remove.’ is displayed until the formatting is completed.
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LOCAL OPERATION Coded store protection Memory cards can have code protected locking applied to a portion of the store locations. This locking prevents the state of write-protection from being changed. This allows users not in possession of the code, to have access to data held in protected stores, without being able to remove the protection. Only users in possession of the code can unlock the protection and change the contents. The same code is needed to adjust the portion of memory locations locked.
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OPERATING MANUAL 2945A Key in the existing code number and press the [ENTER] key. The ’locked’ and the ENTER CODE legends will no longer be shown. Press the [Change Code] key. The inverse video legend ’New Card Code’ is displayed. Key in a new four figure number and press the [ENTER] key. The new code will apply to the card but it will not be protected in the Service Monitor until the next power-up.
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LOCAL OPERATION Error messages There are a number of error messages associated with the store facility, which will be displayed, for approximately 10 seconds, under certain conditions. These are listed below. *** ERROR Store Empty *** *** ERROR Card Not Formatted *** *** ERROR Store Protected *** *** ERROR No Card Present *** *** ERROR No Card Interface *** *** ERROR Card Directory Full *** The recalled store location is empty.
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OPERATING MANUAL 2945A Access The real time clock read-out with its setting facility, is on the MEMORY CARD FORMAT screen and menu. This is accessed by the key sequence, [HELP/SETUP], [Card Setup]. Setting the clock date and time The soft keys on the left of the screen are all relevant to the real time clock. A new date or time can only be set if the clock set locking facility shows ’Enabled’. If it shows ’Locked’ the clock four figure access code must be entered. See ’Locking and enabling’, below.
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LOCAL OPERATION Test results held in the Service Monitor memory stores or on memory cards can also be printed. The procedures for these operations are described earlier in this chapter. See Stores, settings/results, on page 3-82 and Printing from memory cards, on page 3-87. Parallel printer port option Parallel output The parallel printer port option provides an output suitable for direct connection to a parallel drive printer. Fig.
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OPERATING MANUAL 2945A Table 3-2 Rear accessory port connections Contact 1 2 3 4 5 6 7 8 9 Function +5 V Logic line 3 or logic contact 3(a) Logic line 2 or logic contact 2(a) Logic line 1 or logic contact 1(a) Logic line 0 or logic contact 0(a) logic contact 3(b) Logic contact 2(b) Logic contact 1(b) Logic contact 0(b) SW1(a) 5 LINE 0 RELAY SW1(b) 4 LINE 1 FROM LOGIC CIRCUITS 9 RELAY SW1(c) 8 ACCESSORY PORT 3 LINE 2 RELAY SW1(d) 7 2 LINE 3 RELAY 6 +5V 1 C2157 Fig.
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LOCAL OPERATION Setting up Logic line state The state of the logic lines outputs can be set from the logic lines setup menu, accessible by the key sequence, [HELP/SETUP], [Setup], [Setup Page 2], [Logic Lines]. The top four soft keys on the right of the display control the normal state of the logic lines. Pressing these keys will set the options alternately. If the appropriate section of S1 is closed, the output can be set to either logic high or logic low.
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To Printer: Trim A3 printed sheets by 0.75" (19mm) from right edge to clear binder. OPERATING MANUAL 2945A Test mode screen and menu (1.0). HELP/SETUP with lower levels.
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LOCAL OPERATION Fold out diagram number (1.
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To Printer: Trim A3 printed sheets by 0.75" (19mm) from right edge to clear binder. OPERATING MANUAL 2945A Test mode screen and menu (2.0). Tx TEST with next levels.
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LOCAL OPERATION Fold out diagram number (2.
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To Printer: Trim A3 printed sheets by 0.75" (19mm) from right edge to clear binder. OPERATING MANUAL 2945A Test mode screen and menu (3.0). Rx TEST with next levels.
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LOCAL OPERATION Fold out diagram number (3.
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To Printer: Trim A3 printed sheets by 0.75" (19mm) from right edge to clear binder. OPERATING MANUAL 2945A Test mode screen and menu (4.0). Dx TEST with next levels.
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LOCAL OPERATION Fold out diagram number (4.
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To Printer: Trim A3 printed sheets by 0.75" (19mm) from right edge to clear binder. OPERATING MANUAL 2945A Test mode screen and menu (5.0). SYSTEMS with next levels.
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LOCAL OPERATION Fold out diagram number (5.
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To Printer: Trim A3 printed sheets by 0.75" (19mm) from right edge to clear binder. OPERATING MANUAL 2945A Test mode screen and menu (6.0). SPEC ANA with next levels.
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LOCAL OPERATION Fold out diagram number (6.
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To Printer: Trim A3 printed sheets by 0.75" (19mm) from right edge to clear binder. OPERATING MANUAL 2945A Test mode screen and menu (7.0). AF TEST with next levels.
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LOCAL OPERATION Fold out diagram number (7.
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Chapter 4 TECHNICAL DESCRIPTION Contents Overview........................................................................................................................................ 4-2 Power supply .......................................................................................................................... 4-2 The display ............................................................................................................................. 4-3 Tx test mode ..........................
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TECHNICAL DESCRIPTION Overview This simple description is provided to give the user an insight into the working of the Service Monitor at the block diagram level. See Fig. 4-2 Simplified block diagram. The power supply and display unit are described first. The functional circuit blocks of each test mode are then described in sequence. The Service Monitor is of modular construction, comprising a number of printed circuit boards, (at least 15, depending on options included).
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OPERATING MANUAL 2945A An additional requirement is for a charging facility to provide a trickle charge to the DC supply when the instrument is working from the AC supply and a recharge facility from the AC supply when the instrument is not operating. The AC supply enters the instrument through a connector on the rear panel and passes through a fuse and two poles of a triple pole, double throw switch. This switch selects the operate condition, the charge condition or off.
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OPERATING MANUAL 2945A Fig. 4-2 Simplified block diagram Note to Printer: Replace this A4 page with an A3 page of the same number.
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OPERATING MANUAL 2945A Tx test mode When operating in the Tx TEST mode the Service Monitor has to provide a source of modulation for the transmitter being tested and also analyse the RF output signal from the transmitter. Modulation sources The modulating signal is provided by one or both of the audio generators or the data generator and is taken from the AF output connector on the front panel. A B A.F.
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TECHNICAL DESCRIPTION Output from the EPROM is as 8 bit parallel information corresponding to the selected shape and at the repetition frequency instructed by the information latched into the programmable array device. The EPROM output is applied to a digital to analogue converter which, by converting each digital value to the corresponding analogue level, produces the required signal. The mean output level from the digital to analogue converter is constant.
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OPERATING MANUAL 2945A Receiver circuits Input switching TO OVERLOAD WARNING CIRCUIT BNC RF OUT OVERLOAD DETECTOR FROM RF GENERATOR VIA ATTENUATOR ➤ ’N’ TYPE RF IN/OUT TO FIRST FREQUENCY CHANGER VIA ATTENUATOR 0/10dB ATTEN. 25kHz POWER LEVEL 9mV FOR +7dBm AT ’N TYPE’ INPUT TO OVERLOAD WARNING CIRCUIT 20dB ATTEN. ➤ 0/10dB ATTEN. AGC AMPLIFIER 25kHz 1V RMS 25kHz DETECTOR - INTEGRATOR + BNC ANTENNA RF IN OVERLOAD DETECTOR LIMITER RF DETECTOR TO OVERLOAD WARNING CIRCUIT C1411 Fig.
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TECHNICAL DESCRIPTION Overload detection An overload detection circuit is activated if power in excess of 1.0 W is applied to the BNC antenna connector or to the BNC RF output connector. The overload detect lines are activated and trigger the overload warning message from the microprocessor.
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OPERATING MANUAL 2945A Third frequency changer/mixer A third frequency change is made to the signal to achieve a final IF of 10.7 MHz. The local oscillator signal for the third mixer is provided by the voltage controlled oscillator on A10. This oscillator runs at 90 MHz and for normal transmitter testing is locked to the output of a 90 MHz reference oscillator on the second and third oscillator board A9/1. Bandwidth filters The 10.
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TECHNICAL DESCRIPTION output signal will equal the difference in frequency between the original carrier frequency and the original sideband frequency. Either an upper sideband signal or lower sideband signal will produce an output. This will equal the frequency of the applied modulation. The demodulated signal is fed to the input of the audio routeing circuits.
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OPERATING MANUAL 2945A generator will allow the other to function as an AF generator for the Tx TEST mode, but using both as modulation sources will remove both from Tx TEST use. RF generator The RF signal is produced within the monitor by a fractional N controlled oscillator with a range of 1,280.1 MHz to 2,280.0 MHz. This is located on the RF generator oscillator board A13/1.
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TECHNICAL DESCRIPTION digital to analogue converter. This device provides fine level control of the RF signal by applying a DC level to the AM modulator as described earlier. Pre-emphasis filter A 750 µs pre-emphasis filter is included on the audio processor board and is switched into the FM modulation path when selected as part of the Rx TEST set-up. AF measuring circuits The AF output signal from the receiver under test is fed into the AF INPUT connector of the Service Monitor.
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OPERATING MANUAL 2945A AF test mode The AF TEST mode requires a signal source to apply to the circuit or equipment under test and a measuring facility to analyse the resultant output signal. The signal source is provided by the audio generators as for the Tx TEST mode and the AF measuring circuits configured as for the Rx TEST mode. The RF generator and IF local oscillators are disabled. The power metering and modulation metering functions are also disabled.
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OPERATING MANUAL 2945A A11/1 SEE FIG. DETAILED BLOCK DIAGRAM 1ST MIXER A11/1 INPUT/ OUTPUT SWITCHING A2 1359.3 MHz A2 A3 A3 A3 10.7 MHz (10.625 MHz SSB) 3RD MIXER A3 A3 A4/1 A4/1 A4/1 A4/1 LOG 1280 MHz A7-A8 A9/1 1ST LOCAL OSCILLATOR A10 A15 A10 SSB DEMOD OUTPUT 10 MHz REF 400 kHz-1.05 GHz AM MODULATOR TO SQUELCH ON SYSTEMS BOARD B3/1 2ND LOCAL OSCILLATOR A12 A6/1 ONLY PRESENT WHEN SSB OPTION FITTED 3RD LOCAL OSCILLATOR 90 MHz +/- 0.
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TECHNICAL DESCRIPTION Simplified block diagram 4-6 46882-311D
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Chapter 5 ACCEPTANCE TESTING Contents Introduction.................................................................................................................................... 5-2 Results tables .......................................................................................................................... 5-2 Before starting ........................................................................................................................ 5-2 Test equipment ..........................
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ACCEPTANCE TESTING Fig. 5-14 Fig. 5-15 Fig. 5-16 Fig. 5-17 Fig. 5-18 Fig. 5-19 Audio oscilloscope check ......................................................................................... 5-18 Modulation meter FM............................................................................................... 5-20 Modulation analyzer - AM........................................................................................ 5-23 RF frequency meter.......................................................
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OPERATING MANUAL 2945A Test equipment Description Minimum specification Example Frequency counter 400 kHz to 1.05 GHz. 1 Hz resolution, external standard In/Out. IFR* 2440 or EIP 25B RF power meter ± 0.1 dB from 10 MHz to 1 GHz. IFR* 6960/A/B + 6912 and 6920 sensor Measuring receiver −21 dBm to −127 dBm, 2.5 MHz to 1 GHz. HP 8902A + 11772A sensor Spectrum analyzer 400 kHz to 3 GHz, noise floor < −127 dBm. IFR* 2383 Low-noise FM demodulator Residual FM to be less than 2 Hz up to 1 GHz.
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ACCEPTANCE TESTING RF output tests Carrier frequency accuracy This check provides a conventional method of checking the signal generator frequency locking circuitry. It will confirm correct operation of phase lock loop and dividers. Overall accuracy is determined by the instrument’s internal reference standard. Specification Frequency range: 400 kHz to 1.
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OPERATING MANUAL 2945A Table 5-1 Carrier frequencies Frequency 400.000 kHz UUT area checked 2440 range Oscillator, bottom A 1050.00000 MHz Oscillator, top C 500.00000 MHz Oscillator, middle B 188.88888 177.77777 166.66666 155.55555 144.44444 133.33333 122.22222 111.
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ACCEPTANCE TESTING (3) Check that the power meter indicates −21 dBm ± 2 dB. (4) Select N-type output/N-type input mode and check that the level measured is −21 dBm ±2 dB. (5) Press RF IN/OUT [SELECT] until the mode returns to N-type output/antenna input. (6) Repeat steps 3 to 5 for 100 MHz and then in 100 MHz steps up to and including 1000 MHz. ALC linearity (1) Refer to Results table 5-3 on page 5-31. Connect the sensor to the N-type output socket, as shown in Fig. 5-2.
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OPERATING MANUAL 2945A (4) Decrement the output of the UUT in 10 dB steps down to an RF level of −121 dBm measuring the RF level at each step. (5) Repeat steps 2 to 4 for frequencies of 500 and 1000 MHz. Alternative attenuator functional check Spectrum analyzer UUT N TYPE OUTPUT C2583 Fig. 5-4 Attenuator functional check (1) Connect the test equipment as shown in Fig. 5-4. (2) Set the UUT to [Rx TEST], RF IN/OUT [SELECT] N-type output, [RF Gen], [LEVEL] −27 dBm, [∆ INC] 10 dB, [FREQ] 251 MHz.
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ACCEPTANCE TESTING Test equipment Description Spectrum analyzer Minimum specification Example 400 kHz to 3 GHz noise floor better than − 127 dBm at 500 MHz IFR 2383 Residual FM to be less than 2 Hz up to 1 GHz IFR 2305 + IFR 2041 50 Ω sealed load 2 turn 25 mm loop Low-noise FM demodulator Spectrum analyzer UUT BNC SOCKET C2584 Fig. 5-5 Carrier harmonics & spurious check (1) Refer to Results table 5-6 on page 5-33. Connect the Spectrum analyzer to the BNC socket on the UUT, as shown in Fig. 5-5.
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OPERATING MANUAL 2945A Spectrum analyzer UUT 25 mm RF INPUT Two turn loop 25 mm diameter C2585 Fig. 5-6 RF carrier leakage check (7) Refer to Results table 5-8 on page 5-33. Connect the test equipment as shown in Fig. 5-6, with the 50 Ω load connected to the BNC socket of the UUT. (8) Set the UUT to [Rx TEST], RF IN/OUT [SELECT] BNC output, [RF Gen], [LEVEL] −40 dBm, [FREQ] 501.9873 MHz. (9) Tune the Spectrum analyzer to monitor 501.9873 MHz.
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ACCEPTANCE TESTING (12) Refer to Results table 5-9 on page 5-33. Set the UUT to [Rx TEST], RF IN/OUT [SELECT] BNC output, [RF Gen], [LEVEL] 0 dBm, [ FREQ], 1000 MHz, [Mod Gen], [Gen1/Gen2], to select modulation generator 2, and then [LEVEL], 1 kHz. After this key sequence modulation generator 2 should be providing 1 kHz deviation at 1 kHz modulation rate. Modulation generator 1 should be OFF. (13) Set the signal generator into low noise mode 1 and to provide a signal of 55.63889 MHz at 0 dBm.
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OPERATING MANUAL 2945A Modulation meter UUT BNC OUTPUT RF INPUT C2587 Fig. 5-8 Internal AM accuracy checks (1) Refer to Results table 5-10 on page 5-34. Connect the test equipment as shown in Fig. 5-8 (BNC output socket on UUT). (2) Set the UUT to [Rx TEST], RF IN/OUT [SELECT] BNC output, [RF Gen], [LEVEL] 0 dBm, [FREQ] 1.5 MHz, [Mod Gen], [Gen 2], [FREQ] 1 kHz, [LEVEL] 50%. (3) Set the Modulation meter to monitor AM in a 0.3 to 3.4 kHz bandwidth.
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ACCEPTANCE TESTING Frequency modulation Specification Carrier range 400 kHz to 1.05 GHz Accuracy† ±5% ± 10 Hz at 1 kHz modulating frequency. ± 10% ± 10 Hz for modulating frequencies from 50 Hz to 15 kHz. Distortion Less than 1% at 1 kHz for deviation of 5 kHz, CCITT Weighted. † At low modulation levels the residual AM/FM may become significant Test equipment Description Modulation meter Minimum specification Example RF I/P 500 kHz to 1.05 GHz FM Measurement accuracy ±0.
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OPERATING MANUAL 2945A (10) Switch distortion measurement off. (11) Refer to Results table 5-18 on page 5-36. Set the UUT Mod Gen 2 to provide 10 kHz deviation level at a frequency of 50 Hz. (12) Select the 30 Hz to 50 kHz filter on the Modulation meter. (13) Check that the Modulation meter reads 10 kHz deviation ±10% ±10 Hz. Repeat for UUT modulation frequencies of 10 kHz and 15 kHz. AF output tests Audio generator output level Specification Level range: 0.
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ACCEPTANCE TESTING Audio generator distortion Specification Distortion: Less than 0.5% at 1 kHz. Less than 1% from 50 Hz to 15 kHz . Test equipment Description Minimum specification Distortion analyzer Example Capable of measuring distortion from 1 kHz to 15 kHz down to 0.1%. IFR 2965 or HP8903B Distortion analyzer UUT AF GEN OUTPUT AF INPUT C2589 Fig. 5-11 Audio generator signal purity checks (1) Refer to Results table 5-21 on page 5-38.
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OPERATING MANUAL 2945A Specification 0.01 Hz ± frequency standard < 180 Hz Frequency accuracy: 0.1 Hz ± frequency standard >180 Hz (1) Refer to Results table 5-23 on page 5-38. Connect the UUT AF GEN OUT socket to the UUT AF INPUT socket. (2) Set the UUT to [AF TEST], [AF Filter], [50 kHz LP] to set the Audio Input filter to 50 kHz Low-pass. (3) Set [Audio Gen], [LEVEL] 1 V, [FREQ] 10 Hz. Audio generator 2 should be switched OFF.
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ACCEPTANCE TESTING UUT LF generator AF INPUT 50Ω DVM VOLTMETER INPUT TERMINALS C2590 Fig. 5-12 Audio frequency meter check Audio voltmeter Specification Level accuracy: ±3% ±3 mV ± resolution 20 Hz to 50 kHz (DC and 20 Hz to 50 kHz when DC coupled) Resolution: 1 mV or 1% of reading. Test equipment Description 5-16 Minimum specification LF generator 50 Hz to 50 kHz 30 mV to 5 V RMS. DC power supply 0 to 50 V DVM DC measurement and AC measurement 20 Hz to 50 kHz.
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OPERATING MANUAL 2945A LF generator UUT AF INPUT AF GEN OUTPUT DVM VOLTMETER INPUT TERMINALS C2591 Fig. 5-13 Audio voltmeter level accuracy checks (6) Set the UUT AF filter to 50 kHz LP. (7) Set the LF generator to frequency 50 Hz level 1 V RMS (adjust until DVM indicates as close to 1 V as possible). Check that the level indicated on the UUT voltmeter is within ±3% ±3 mV ± resolution of the level indicated on the DVM.
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ACCEPTANCE TESTING LF generator UUT AF INPUT AF GEN OUTPUT DVM VOLTMETER INPUT TERMINALS C2591 Fig. 5-14 Audio oscilloscope check (1) Refer to Results table 5-27 on page 5-40. Connect the equipment as shown in Fig. 5-14, connecting to the AF input of the UUT. (2) Set the UUT to [AF TEST], [Scope/Bar], [Scope], [AC DC] set to AC coupling. Set the Scope timebase to 200 µs/div.
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OPERATING MANUAL 2945A AF distortion & SINAD meter Specification Frequency range: 1 kHz. Distortion meter accuracy ±5% of reading ± 0.5% distortion. SINAD meter accuracy ± 1 dB. (1) Refer to Results table 5-29 on page 5-41. Connect UUT AF INPUT to UUT AF GEN OUT. (2) Set the UUT to [AF TEST], [Audio Gen], [LEVEL] 1 V. Press [Gen 1/Gen2] to select AF Gen 2, then [FREQ] 400 Hz, [LEVEL] 20 mV, [ON]. This should cause AF Gen 1 to be set to 1 kHz, 1 V, and AF Gen 2 to 400 Hz, 20 mV.
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ACCEPTANCE TESTING Test equipment Description Minimum specification Example RF signal generator 5.5 MHz to 1 GHz Deviation 0 to 75 kHz Modulation rate 10 Hz to 15 kHz. IFR 2041 Modulation meter RF I/P 5.5 MHz to 1 GHz FM Measurement accuracy ±0.5% of reading ±1 least significant changing digit at 1 kHz mod rate for deviation >5 kHz. IFR 2305 Power splitter 6 dB 50 Ω 5.5 MHz to 1 GHz.
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OPERATING MANUAL 2945A (9) Select the 300 Hz high-pass filter by pressing [more], [300Hz HP], and check that the UUT still indicates 20 kHz deviation. (Functional check only.) (10) Select the 3 kHz low-pass filter and check that the UUT still indicates 20 kHz deviation. (Functional check only.) (11) Refer to Results table 5-31 on page 5-41. Select the 300 Hz low-pass filter by pressing [more], [300Hz LP].
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ACCEPTANCE TESTING (31) Refer to Results table 5-35 on page 5-42. Set the RF signal generator to provide a signal of 300 MHz at 6 dBm with 5 kHz deviation at 1 kHz modulation rate. (32) On the UUT select the 0.3 to 3.4 kHz AF filter and the 30 kHz IF filter. (33) On the UUT switch distortion measurement ON and check that the distortion reading indicates less than 2%.
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OPERATING MANUAL 2945A Signal generator RF OUTPUT Modulation meter UUT ANTENNA INPUT RF INPUT Splitter C2592 Fig. 5-16 Modulation analyzer - AM (1) Refer to Results table 5-36 on page 5-42. Connect the equipment as shown in Fig. 5-16, connecting the incoming signal to the antenna input socket of the UUT. (2) Set the Modulation meter to monitor AM in a 50 Hz to 15 kHz bandwidth, Noise averaging on. (3) Set the UUT to [Tx TEST], RF IN/OUT [SELECT] antenna input socket, [Mod Meter].
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ACCEPTANCE TESTING (14) Refer to Results table 5-39 on page 5-43. Select the Oscilloscope on the UUT. Set a timebase of 500 µs/div and a vertical scale of 10%/div. (15) Set the RF signal generator to provide 60% AM, adjusting this level until the demodulated signal on the display occupies the full six divisions. Check that the modulation indicated on the external Modulation meter is 60% ±10%. (16) Remove the splitter and Modulation meter and connect the RF signal generator directly to the UUT BNC input.
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OPERATING MANUAL 2945A (1) Refer to Results table 5-41 on page 5-43. Connect the equipment as shown in Fig. 5-17, connecting the incoming signal to the antenna input socket of the UUT. Lock the Service Monitor external standard input to the external standard output of the signal generator. (2) Set the UUT to [Tx TEST], RF IN/OUT [SELECT] antenna BNC input socket.
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ACCEPTANCE TESTING Signal generator UUT N TYPE OUTPUT EXTERNAL STANDARD OUTPUT C2594 Fig. 5-18 RF spectrum analyzer checks (1) Refer to Results table 5-44 on page 5-44. Set the UUT to [SPEC ANA], [Centre Freq] 101 MHz, [Span] 1 kHz, BNC antenna input socket, [Ref Level] -30.0 dBm. (2) With nothing connected to the UUT, check that the noise floor is on or below the bottom graticule line of the display. (80 dBm dynamic range.) (3) Connect the equipment as shown in Fig.
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OPERATING MANUAL 2945A (15) Check that the difference between the highest and the lowest point noted is less than 1.1 divisions. (16) To functionally test the look/listen facility first set the following on the UUT. Select the [Return] , soft key at the bottom right hand corner of the display and then [Return] , [Centre Freq], 300 MHz, [Return], [Vert Scale], toggle [10/2DB /DIV] until 10 dB per division is displayed, [Span], 100 kHz, [Res BW], [Auto Res BW].
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ACCEPTANCE TESTING UUT Signal generator N TYPE INPUT Splitter RF OUTPUT Pad Pad Power meter Pad Power sensor RF amplifier SENSOR INPUT C2595 Fig. 5-19 RF broad band power meter checks Notes 5-28 (1) Set the calibrated power source to provide 100 MHz and 100 mW. Press [SELECT] on the UUT to select N-type input/output, i.e. both LEDs above the N-type socket on. Note the level on the UUT broad band power meter and check that it is within the stated specification.
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OPERATING MANUAL 2945A Options if fitted Options 2, 10, 11, 12, 13, 14, 15, 16 & 22 Option 10 - NMT Option 11 - AMPS Option 12 - TACS Option 13 - MPT1327 Option 14 - PMR TEST Option 15 - EDACS Radio Option 16 - EDACS Repeater Option 22 - POCSAG Decode Option 2 - Analog system card required for above options. The Analog system options make use of the circuitry already tested under the standard instrument tests but also have an additional circuit card (option 2 ).
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ACCEPTANCE TESTING Acceptance Test Results Tables For 2945A [ ], 2946A [ ], serial number _ _ _ _ _ _ / _ _ _ Results table 5-1 Carrier frequency accuracy Frequency Lower limit 400.000 kHz Upper limit 399.999 400.001 Result _______ 1050.00000 MHz 1049.999999 1050.000001 _______ 500.00000 MHz 499.999999 500.000001 _______ 188.88888 MHz 188.888879 188.888881 _______ 177.77777 MHz 177.777769 177.777771 _______ 166.66666 MHz 166.666659 166.666661 _______ 155.55555 MHz 155.
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OPERATING MANUAL 2945A Results table 5-3 ALC linearity at 10 MHz 46882-311D Level (dBm) Lower limit Upper limit Result −21 −23.0 −19.0 _______ −22 −24.0 −20.0 _______ −23 −25.0 −21.0 _______ −24 −26.0 −22.0 _______ −25 −27.0 −23.0 _______ −26 −28.0 −24.0 _______ −27 −29.0 −25.0 _______ −28 −30.0 −26.0 _______ −29 −31.0 −27.0 _______ −30 −32.0 −28.0 _______ −31 −33.0 −29.0 _______ −32 −34.0 −30.0 _______ −33 −35.0 −31.0 _______ −34 −36.0 −32.
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ACCEPTANCE TESTING Results table 5-4 ALC linearity at 500 MHz Level (dBm) Lower limit Upper limit Result −21 −23.0 −19.0 _______ −22 −24.0 −20.0 _______ −23 −25.0 −21.0 _______ −24 −26.0 −22.0 _______ −25 −27.0 −23.0 _______ −26 −28.0 −24.0 _______ −27 −29.0 −25.0 _______ −28 −30.0 −26.0 _______ −29 −31.0 −27.0 _______ −30 −32.0 −28.0 _______ −31 −33.0 −29.0 _______ −32 −34.0 −30.0 _______ −33 −35.0 −31.0 _______ −34 −36.0 −32.0 _______ −35 −37.
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OPERATING MANUAL 2945A −38 −40.0 −36.0 _______ Results table 5-6 Carrier harmonic test points at 0 dBm Frequency (MHz) Second harmonic (MHz) Result Third harmonic (MHz) Result Upper limit (dBc) 0.4 0.8 _______ 1.2 _______ −20 100.0 200.0 _______ 300.0 _______ −20 300.0 600.0 _______ 900.0 _______ −20 500.0 1000.0 _______ 1500.0 _______ −20 700.0 1400.0 _______ 2100.0 _______ −20 900.0 1800.0 _______ 2700.0 _______ −20 1000.0 2000.0 _______ 3000.
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ACCEPTANCE TESTING Results table 5-10 AM versus carrier frequency (50% depth at 1 kHz rate) Carrier frequency (MHz) Lower limit (%) Upper limit (%) 1.5 Result (%) 45.5 54.5 _______ 50 45.5 54.5 _______ 100 45.5 54.5 _______ 150 45.5 54.5 _______ 200 45.5 54.5 _______ 250 45.5 54.5 _______ 300 45.5 54.5 _______ 350 45.5 54.5 _______ 400 45.5 54.
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OPERATING MANUAL 2945A Results table 5-12 AM linearity (100 MHz, 0 dBm at 1 kHz rate) Am depth set (%) Lower limit (%) Upper limit (%) 6.35 Result (%) 5 3.65 10 8.3 11.7 _______ _______ 20 17.6 22.4 _______ 30 26.9 33.1 _______ 40 36.2 43.8 _______ 50 45.5 54.5 _______ 60 54.8 65.2 _______ 70 64.1 75.9 _______ 85 79.1 91.95 _______ Results table 5-13 AM versus modulation frequency (100 MHz, 85% depth) AM frequency (kHz) Lower limit (%) Upper limit (%) Result (%) 0.
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ACCEPTANCE TESTING Results table 5-15 FM versus carrier frequency (at 10 kHz deviation 1 kHz rate) Carrier frequency (MHz) Lower limit (kHz) 0.5 Upper limit (kHz) Result 9.490 10.510 _______ 10 9.490 10.510 _______ 100 9.490 10.510 _______ 200 9.490 10.510 _______ 300 9.490 10.510 _______ 400 9.490 10.510 _______ 500 9.490 10.510 _______ 600 9.490 10.510 _______ 700 9.490 10.510 _______ 800 9.490 10.510 _______ 900 9.490 10.510 _______ 925 9.490 10.
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OPERATING MANUAL 2945A Results table 5-19 Audio generator 1 output level AF generator 1 frequency (Hz) Level (mV) Lower limit (mV) Upper limit (mV) Result 1000 4000 3799 4201 _______ 50 4000 3799 4201 _______ 150 4000 3799 4201 _______ 500 4000 3799 4201 _______ 2000 4000 3799 4201 _______ 5000 4000 3799 4201 _______ 10000 4000 3799 4201 _______ 15000 4000 3799 4201 _______ 1000 20.0 18.9 21.1 _______ 1000 400.0 379.9 420.
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ACCEPTANCE TESTING Results table 5-21 Audio generator 1 distortion AF generator 1 frequency (Hz) Level (mV) Distortion upper limit (%) 1000 4000 0.5 _______ 0.5 _______ 1000 100.0 Result 2000 4000 1.0 _______ 5000 4000 1.0 _______ 15000 4000 1.0 _______ Results table 5-22 Audio generator 2 distortion AF generator 2 frequency (Hz) Level (mV) Distortion upper limit (%) 1000 4000 0.5 _______ 0.5 _______ 1000 100.0 Result 2000 4000 1.0 _______ 5000 4000 1.
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OPERATING MANUAL 2945A Results table 5-24 Audio generator 2 frequency (functional) AF generator 2 setting Lower limit Upper limit Result 10 Hz 9.9 Hz 10.1 Hz _______ 500 Hz 499.9 Hz 500.1 Hz _______ 1.0000 kHz 999.9 Hz 1000.1 Hz _______ 1.1111 kHz 1.1110 kHz 1.1112 kHz _______ 2.2222 kHz 2.2221 kHz 2.2223 kHz _______ 3.333 kHz 3.3328 kHz 3.3332 kHz _______ 4.444 kHz 4.4438 kHz 4.4442 kHz _______ 5.555 kHz 5.5548 kHz 5.5552 kHz _______ 6.666 kHz 6.6658 kHz 6.
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ACCEPTANCE TESTING Results table 5-26 Audio voltmeter accuracy Frequency † DVM reading (mV) UUT coupling UUT * lower limit (mV) ‡ UUT * upper limit (mV) † 25.1 34.
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OPERATING MANUAL 2945A Results table 5-28 Oscilloscope LF generator frequency UUT timebase 10 Hz DVM lower limit DVM upper limit Result 50 ms/div 50 µs/div 2.015 V 2.227 V _______ 10 kHz 2.015 V 2.227 V _______ 20 kHz 50 µs/div 2.015 V 2.227 V _______ Results table 5-29 Distortion & SINAD meter Distortion/SINAD set Lower limit Upper limit Result 1.4% 2.6 % _______ 25% 23.2% 26.8 % _______ 12 dB 11.
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ACCEPTANCE TESTING Results table 5-33 FM demodulation oscilloscope Carrier frequency (MHz) Deviation (kHz) Lower limit (kHz) Upper limit (kHz) 300 75 67.5 82.5 Result _______ Results table 5-34 FM demodulation output socket Carrier frequency (MHz) 300 Deviation (kHz) Lower limit 75 Upper limit 4.77 V 5.
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OPERATING MANUAL 2945A Results table 5-38 AM measurement versus AM depth (1 kHz rate) Depth (%) Lower limit (%) † 5 Upper limit (%) † 3.75 6.25 Result _______ 20 18 22 _______ 50 46.5 53.
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ACCEPTANCE TESTING Results table 5-42 RF frequency meter (at −13 dBm (0.05 mW) antenna input autotuned) Carrier frequency (MHz) Lower limit (MHz) Upper limit (MHz) Result 1000 999.999999 1000.000001 _______ 500 499.999999 500.000001 _______ 10 9.999999 10.000001 _______ Results table 5-43 Internal frequency standard Carrier frequency (MHz) Lower limit (MHz) Upper limit (MHz) Result 999.999500 100.000500 _______ 999.999750 100.
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OPERATING MANUAL 2945A Results table 5-45 RF broad band power meter (N-type input) Frequency (MHz) Input level (dBm) Lower limit (dBm) Upper limit (dBm) Result 11 20 19.4 20.5 _______ 100 20 19.4 20.5 _______ 200 20 19.4 20.5 _______ 300 20 19.4 20.5 _______ 400 20 19.4 20.5 _______ 500 20 19.4 20.5 _______ 600 20 19.4 20.5 _______ 700 20 19.4 20.5 _______ 800 20 19.4 20.5 _______ 900 20 19.4 20.5 _______ 1000 20 19.4 20.5 _______ 100 20 19.
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Appendix A DIRECTIONAL POWER HEADS Contents Features..........................................................................................................................................A-7 Performance data - power head only..............................................................................................A-8 Performance data - in conjunction with 2945A............................................................................A-10 Additional parts associated with directional power head ....
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DIRECTIONAL POWER HEADS Precautions These terms have specific meanings in this manual: WARNING information to prevent personal injury. information to prevent damage to the equipment. important general information.
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OPERATING MANUAL 2945A Précautions Les termes suivants ont, dans ce manuel, des significations particulières: WARNING contient des informations pour éviter toute blessure au personnel. contient des informations pour éviter les dommages aux équipements. contient d'importantes informations d'ordre général.
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DIRECTIONAL POWER HEADS Vorsichtsmaßnahmen Diese Hinweise haben eine bestimmte Bedeutung in diesem Handbuch: WARNING dienen zur Vermeidung von Verletzungsrisiken. dienen dem Schutz der Geräte. enthalten wichtige Informationen. Gefahrensymbole Die Gefahrensymbole auf den Geräten sind wie folgt: Symbol Gefahrenart ! Hochfrequenz Sicherheit Dieses Gerät wurde in Übereinstimmung mit BS4743 und IEC 348 entwickelt und geprüft.
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OPERATING MANUAL 2945A Precauzioni Questi termini vengono utilizzati in questo manuale con significati specifici: WARNING riportano informazioni atte ad evitare possibili pericoli alla persona. riportano informazioni per evitare possibili pericoli all’apparecchiatura. riportano importanti informazioni di carattere generale.
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DIRECTIONAL POWER HEADS Precauciones Estos términos tienen significados específicos en este manual: WARNING contienen información referente a prevención de daños personales. contienen información referente a prevención de daños en equipos. contienen información general importante.
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OPERATING MANUAL 2945A Features This accessory for IFR instruments is used to measure forward power, reverse power and VSWR in coaxial RF transmission lines and antenna systems. There are two versions as follows:Frequency range 1 to 50 MHz (HF) 25 to 1000 MHz (UHF) Part no. 54421-002L 54421-003J There are no controls fitted to the Directional Power Head. There are RF line input and output connectors, and a DIN socket for the lead to the Service Monitor.
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DIRECTIONAL POWER HEADS Performance data - power head only Frequency range: Power measurement (either direction) Indication range for CW: HF version UHF version 1 MHz to 50 MHz. 25 MHz to 1000 MHz. See Fig. 1-2. See Fig. 1-3. 5 mW to 400 W. 5 mW to 400 W at 25 to 520 MHz, 5 mW to 200 W at 1000 MHz. Indication range for PEP: 1 to 400 W. 1 to 400 W at 25 to 520 MHz, 1 to 200 W at 1000 MHz. Maximum applied PEP: 1 kW. 1 kW at 25 to 100 MHz, 200 W at 1000 MHz.
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OPERATING MANUAL 2945A RF connectors Type: N sockets. N sockets. Characteristic impedance: 50 Ω nominal. 50 Ω nominal. Insertion SWR: <1.1:1 (return loss >26.4 dB) at 1 to 50 MHz. <1.1:1 (return loss >26.4 dB) at 25 to 1000 MHz. Insertion loss: <0.05 dB. <0.35 dB at up to 520 MHz, <0.65 dB at 520 to 1000 MHz. Output connector Type: DIN 7-pin socket, standard Lead Assembly (3 m) to ACCESSORY socket on Service Monitor. Dimensions and weight Height: 52 mm. 52 mm. Width: 108 mm. 108 mm.
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DIRECTIONAL POWER HEADS Performance data - in conjunction with 2945A When the Power Head is used in conjunction with the Communications Service Monitor 2945A, the performance is identical to that of the Power Head alone with the exceptions and additions given below. HF version UHF version Power measurement Resolution: 1 mW or 0.1 dB Indication: 3 digits Setting: Automatic ranging using 0 to 1, 0 to 3 and 0 to 10 scales.
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OPERATING MANUAL 2945A CW POWER CW POWER MAX SAFE POWER MA 1000W 1000W X S AFE PO WE R CW INDICATION ONLY 100W 100W 10W 10W 1W 1W 100mW 100mW 10mW 10mW CW INDICATION ONLY CW INDICATION ONLY 1mW 1mW 1 10 20 30 40 50 FREQUENCY MHz Fig. A-1 Power range of HF directional power head 46882-311D 200 400 600 800 1000 FREQUENCY MHz = PEP INDICATION RANGE = PEP INDICATION RANGE = CW FULL SPEC. RANGE 25 C1377 = CW FULL SPEC. RANGE C1378 Fig.
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DIRECTIONAL POWER HEADS VSWR CURVE BETWEEN POINTS A & B REPRESENTS MINIMUM POWER REQUIRED FOR ACCURATE VSWR MEASUREMENTS 100:1 FULL SPEC. LIMIT OF HF POWER HEAD AND MAX. INDICATION LIMIT OF UHF POWER HEAD UP TO 520 MHz. SEE NOTE. FULL SPEC. LIMIT OF UHF POWER HEAD. EXTENDS TO 200 W UP TO 200 MHz. SEE NOTE. INDICATION ONLY FOR THESE SIGNAL LEVELS 3:1 A NOTE REFER TO FIG. 1-2 FOR INDICATION RANGE AND MAX.
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OPERATING MANUAL 2945A Table A-1 Conversion of VSWR to return loss VSWR Return loss (dB) VSWR Return loss (dB) VSWR Return loss (dB) VSWR Return loss (dB) 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 ∞ 46.1 40.1 36.6 34.2 32.3 30.7 29.4 28.3 27.3 26.4 25.7 24.9 24.3 23.7 23.1 22.6 22.1 21.7 21.2 20.8 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 1.29 1.30 1.32 1.34 1.36 1.38 1.40 1.42 1.44 1.46 1.48 1.50 1.52 20.4 20.1 19.7 19.4 19.1 18.8 18.
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DIRECTIONAL POWER HEADS Using the directional power head accessory General The supplied accessory consists of the Power Head together with the 3 metre Cable Assembly. Power supply No additional power supply is required. 12 V DC is supplied to the Power Head from the Service Monitor, through the cable assembly. Procedure WARNING RF HAZARD. No attempt should be made to connect the Directional Power Head to an RF line until the "Operating Precautions" on page v have been noted.
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OPERATING MANUAL 2945A The bar charts can be set for auto-ranging or manual range selection. Repeated presses of the [Bchart Select] key selects each bar chart in turn. The selected bar chart is indicated by an A or H being shown in inverse video at the left end. Pressing the [Autorange] key will switch the selected bar chart to auto-ranging, indicated by an inverse video A.
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DIRECTIONAL POWER HEADS Technical description Directional coupler assembly The directional coupler is connected in series with the RF line under test and senses forward and reverse RF power. The coupler has two outputs, one for forward power and the other for reverse power. Because the coupler can be connected in either direction on the RF line, either output could represent forward or reverse power. Each output from the coupler is routed to an RF detector.
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OPERATING MANUAL 2945A DIRECTIONAL COUPLER CH. 1 +12V FROM TEST SET RF LINE UNDER TEST CH. 2 TO CHANNEL 2 RF DETECTOR AND CHANNEL 2 CIRCUIT HYBRID POWER SUPPLY & OSCILLATOR CIRCUIT HYBRID CONTROL CIRCUIT HYBRID CONTROL FROM TEST SET 1 kHz RF DETECTOR (CHANNEL 1) CW PATH INTEGRATOR CW AGC ➤ CHANNEL 1 POWER LEVEL TO TEST SET PEP LF DETECTOR (CHANNEL 1) DIRECTIONAL COUPLER ASSEMBLY PEAK BUFFER PEP PATH CHANNEL 1 CIRCUIT HYBRID C1363 Fig.
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Appendix B LIGHT-WEIGHT DIRECTIONAL POWER HEADS Contents Features..........................................................................................................................................B-7 Performance data ...........................................................................................................................B-7 Using the Light-weight Directional Power Head accessory...........................................................B-9 General ..................................
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LIGHT-WEIGHT DIRECTIONAL POWER HEADS Precautions WARNING These terms have specific meanings in this manual: WARNING Information to prevent personal injury. Safety This product has been designed and tested in accordance with IEC1010-1 (BS EN61010-1) ‘Safety requirements for electrical equipment for measurement, control and laboratory use.’ WARNING ! RF hazard When measuring high VSWR ratios, hazardous voltages may be present on the line due to standing waves.
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OPERATING MANUAL 2945A Précautions WARNING Les termes suivants ont, dans ce manuel, des significations particulières: WARNING contient des informations pour éviter toute blessure au personnel. Sécurité Ce produit a été conçu et testé conformément à la norme IEC 1010-1 (BS EN 61010-1) recommandations de sécurité des équipements électriques pour la mesure, le contrôle et l’utilisation en laboratoire. WARNING ! Danger RF Lors de la mesure de T.O.S.
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LIGHT-WEIGHT DIRECTIONAL POWER HEADS Vorsichtsmaßnahmen WARNING Diese Hinweise haben eine bestimmte Bedeutung in diesem Handbuch: WARNING dienen zur Vermeidung von Verletzungsrisiken. Sicherheit Dieses Produkt wurde in Übereinstimmung mit der IEC 1010-1 Norm (BS EN 61010-1) für “Sicherheitsanforderungen an elektrische Geräte in der Meßtechnik, für Steuerungen oder im Laboreinsatz” entwickelt und geprüft.
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OPERATING MANUAL 2945A Precauzioni WARNING Questi termini vengono utilizzati in questo manuale con significati specifici: WARNING riportano informazioni atte ad evitare possibili pericoli alla persona. Sicurezza Questo prodotto è stato progettato e collaudato in accordo con le norme IEC1010-1 (BS EN610101) “Safety requirements for electrical equipment for measurement, control and laboratory use” (Requisiti di sicurezza per apparati elettrici di misura, controllo e di laboratorio).
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LIGHT-WEIGHT DIRECTIONAL POWER HEADS Precauciones WARNING Estos términos tienen significados específicos en este manual: WARNING contienen información referente a prevención de daños personales. Seguridad Este producto ha sido diseñado y comprobado de acuerdo con la norma IEC 1010-1 (BS EN610101) sobre “Necesidades de seguridad para equipos eléctricos de medida, control y laboratorio.
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OPERATING MANUAL 2945A Features This accessory is used to measure forward power, reverse power and VSWR in coaxial RF transmission lines and antenna systems. There are two versions as follows:70 MHz to 1 GHz 400 MHz to 1 GHz 54421-016 54421-018 There are no controls fitted to the Light-weight Directional Power Head. RF line input and output connections are by ’N type’ connectors. A multicore lead with an 8way DIN connector at the end supplies the connection to the service monitor.
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LIGHT-WEIGHT DIRECTIONAL POWER HEADS Dimensions and weight Dimensions Height 30 mm Width 75 mm (body only), 110 mm (inc.
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OPERATING MANUAL 2945A Using the Light-weight Directional Power Head accessory General The Light-weight Directional Power Head can only be used with the Communications Service Monitor 2945A if the adaptor 46884/789 is used. This is either supplied with the Light-weight Directional Power Head as an accessory kit or can be obtained as a separate item. See the performance data section of this appendix. Power supply No additional power supply is required.
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LIGHT-WEIGHT DIRECTIONAL POWER HEADS B2609 Fig. B-2 Directional Power meter screen (Light-weight DPH) The power head is now installed and the service monitor ready to make directional power measurements. Ensure that the transmitter power is OFF and an antenna or load is connected to the transmitter. The RF connections should be made so that the signal path from the transmitter to the antenna is in series, through the power head, in the direction of the arrow on the front panel.
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Index A D AC power supply input........................................... 3-8 AC supply............................................................... 4-2 Acceptance test results tables ............................... 5-30 Acceptance testing.................................................. 5-1 Acceptance tests ..................................................... 5-2 Accessory connector, front panel ........................... 3-7 Accessory port, rear optional................................
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INDEX H N Hard copy ............................................................. 3-89 Harmonic analysis, RF.......................................... 3-21 Hold display ........................................................... 3-7 N Type connector ................................................... 4-9 Naming conventions................................................. iv O I IF circuits.............................................................. 4-10 Illumination ..................................
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OPERATING MANUAL 2945A Mode ................................................................ 4-14 Setting up.......................................................... 3-53 Span adjustment.................................................. 3-6 SSB input sensitivity ............................................ 3-21 SSB transmitter frequency.................................... 3-31 Stores, settings/results .......................................... 3-82 Supply, 36 V.............................................