User manual

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Horizontal System
5.3 Acquisition modes
The acquisition modes are selected by pressing the AC-
QUIRE
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key. This opens a display menu which offers the
following acquisition modes:
5. 3.1 Roll
Thisacquisitionmodeisintendedspecicallyforvery
slow signals, with the untriggered signal „rolling“ across
the screen from right to left (requires signals slower than
200 kHz). The R&S®HMO3000 series uses a ring buffer to
store the signal values in roll mode. Simply put, the instru-
mentwritestherstdivisiontotherststoragespace,the
second division to the second storage space, etc. Once
thestorageisfull,theinstrumentoverwritestherststo-
rage space with the data of the most recent measurement
value. This creates a „ring“ or cycle run, similar to a ticker.
5.3.2 Arithmetic
The soft menu ARITHMETIC offers following menu items:
❙ REFRESH: This mode allows the capture and display of
current signals.
❙ ENVELOPE: In this mode, you can use the universal knob
in the Cursor/Menu section of the control panel to set the
number of signal periods for averaging, available in
powers of 2 from 2 to 1024 (requires repetitive signals).
❙ AVERAGE: In this mode, you can use the universal knob
in the Cursor/Menu section of the control panel to set the
number of signal periods for averaging, available in
powers of 2 from 2 to 1024 (requires repetitive signals).
❙ SMOOTH: The function SMOOTH is used to calculate
the mean value from several adjacent sampling points.
The result is a smooth waveform. This function is used for
non-periodic signals.
❙ FILTER: In this mode, you can activate a lowpasslter
with adjustable cut off frequency to suppress unwanted
high frequency interferences. The cut off frequency can
be set based on the sampling frequency. The minimum
setting is 1/100 of the sampling frequency and the
maximum value is 1/4 of the sampling rate. You can select
this setting with the universal knob.
❙
5.3.3 Peak Detect
This mode is used for very large time base settings to
detect even short signal changes. You can also deactivate
this function within the menu (OFF) or you can select the
automatic switching mode (AUTO). The following condi-
tions must be met to activate the PEAK DETECT mode:
❙ Function HIGH RESOLUTION is deactivated
❙ None of the serial or parallel buses are active
During peak detection, the oscilloscope distinguishes bet-
ween two types:
❙ Acquisition peak detection:
Each A/D converter converts at the full sampling rate (no
Interlace mode), even if results have not been written to
the acquisition memory at full sampling rate (for slow time
The ZOOM feature is not available in the roll mode (also refer to
Chap. 5.5 ZOOM Function)
5 Horizontal System
In the HORIZONTAL system
section, users can select time
base settings for capturing,
trigger time position, zoom
functions, acquisition modes,
marker functions and search
functions. Knobs allow you to
set time base and trigger time
position. A menu enables you
to select the desired acquisi-
tion mode. A separate key is
available to activate the zoom.
Use the arrow keys
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and the SET/CLR key to select
marker functions.
5.1 Acquisition modes RUN and STOP
The acquisition mode can be selected with the RUN/
STOP key
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In Run mode signals are shown on the screen
according to the selected trigger conditions, discarding
previously captured signals with each new capture. If you
wish to analyze a captured signal on the screen without
overwriting it, capture must be stopped by pressing the
RUN/STOP key. While in STOP mode, you may not capture
new signals and the key is illuminated in red.
5.2 Time Base Settings
The TIME/DIV knob in the HORIZONTAL section of the
control panel is used to change the time base. The current
time base setting (e.g.”TB: 500 ns”) is displayed in the up-
per right above the graticule. To the right of the display you
can see the trigger time position in relation to the default
setting. The default setting shows the trigger time position
in the center of the display, with 50% of the signal display
before and 50% after this trigger position. The X-POSITION
knob
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allows continuous adjustment of the x position.
The maximum values allowed depend on the time base
setting.
Pushing the SET/CLR key resets the value to its reference
position as long as the marker or search functions have not
been applied. The arrow keys
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allow you to change
theXpositionbyaxedamountof5divisionsinthe
respective direction. The MENU
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key opens a menu to
determine the function for the arrow keys
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and the
SET/CLR key. As described above, these keys allow you to
set the X position. Alternatively, you can use them to mark
events within the signal with the option to navigate bet-
ween up to 8 markers. In the submenu NUMERIC INPUT
you can enter any horizontal position directly. This menu
also allows you to activate and set search functions. You
can also set the TIME REFERENCE (position for the trigger
reference point, from -5 divisions to +5 divisions with 0
being the center and default setting).
Fig. 5.1: Control panel of the
horizontal system
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