Operating instructions

LOCAL OPERATION
3-89
Oscilloscope
The digital oscilloscope option is available from within the Tx TEST, Rx TEST and AF TEST
modes. There are two display functions:
The standard display with a viewing area of approximately 38 × 70 mm.
The expanded display with a viewing area of approximately 63 × 96 mm.
The oscilloscope display may or may not be shown when the Tx TEST, Rx TEST or AF TEST
modes are selected. This is dependent on the last use of the selected test mode
, and the selection
made using the [Power Up From] key on
setup page 2.
To access the oscilloscope function from a bar chart display, press the [scope/bar] key: the first
press will show the standard display, the second press will show the expanded display, the third
press will return to the bar chart display.
Setting up
The Y sensitivity and the timebase ranges of the oscilloscope are set from the right hand soft keys.
The current settings are shown above the oscilloscope display.
When in Rx TEST and AF TEST modes, the Y (vertical) input is by the AF input connector . The
Y sensitivity is switchable in a 1, 2, 5 sequence, from 10 mV/division to 20 V/division. The
[AC/DC] key selects AC or DC coupling into the oscilloscope.
When in Tx TEST mode, the Y input is taken directly from the modulation meter output. The Y
axis is calibrated to display modulation level. FM ranges are from 0.5 kHz/division to
25 kHz/division. AM ranges are 5%/division, 10%/division and 20%/division.
The horizontal timebase has ranges of 100 µs/division to 5 s/division in a 1, 2, 5 sequence.
The soft keys have the following functions, (top to bottom):-
[ G ]
Increases Y Sensitivity
by one range per key press.
[ L ]
Decreases Y Sensitivity
by one range per key press.
[ D ]
Increases Time/Division
by one range per key press.
[ C ]
Decreases Time/Division
by one range per key press.
[Scope/Bar]
Steps to Expanded display or
Bar chart display
[Return]
(Standard)
Returns display and menu to
Tx TEST, Rx TEST or AF Test.
[Persistence]
(Expanded)
Steps persistence setting through
Off, Low Med High Inf.
The vertical position of the oscilloscope trace can be adjusted using the POSITION rotary control.
The horizontal sweep trigger can be set for repetitive or single sweep, set by the scope mode keys
(Item 15 on fig 3-1, Front panel).
With repetitive mode selected, the trace will free-run, re-triggering on the positive-going edge of
the signal, at the end of each sweep. In the absence of a signal the trace will auto-trigger.
With single sweep selected, the first positive going signal will trigger a sweep. The [SINGLE]
key must be pressed to re-arm the trigger circuit before another sweep can be triggered.