AOR SDU5500 Manual page 24

Section 5-1
If you wish to toggle the attenuator on / off, press ATT This affects the gain at the receiver's front
end and sensitivity of the companion radio. The legend "ATT : ON / OFF" confirms attenuation setting of
the companion radio, this is not available in 'Other' radio operation.
If you wish to toggle the SDU5500 input gain, press GAIN This affects the gain of the SDU5500
and has no effect on the sensitivity of the companion radio. The base line of the SDU5500 is equivalent
to -40dBm in HIGH and -10dBm in LOW. The legend "GAIN" confirms the status of gain setting.
Select menu 3... selects SDU operating mode
3 PREV SPECT STRES CHANL - NEXT
If using "Other" companion radio: 2 PREV SPECT STRES - - NEXT
For normal spectrum analyser operation, press SPECT , this is the default. Use this key to return
from STRES (step resolution mode) or CHANL (channel scope mode). The legend "OP.MODE" confirms
current selection.
To activate step resolution mode, press STRES . In 'step resolution mode', ONLY the wanted steps
are checked for activity rather than the whole band, this is particularly useful when you know the tuning
steps used on a particular band and don't want to view in-between the channel allocations. To achieve
this, the LCD-step is automatically forced to equal the tuning step of the companion radio. You cannot
manually set the SPAN, by necessity it has to be calculated by the SDU5500. STRES mode is
confirmed by the legend "OP.MODE : STRES" on the LCD. To return to a standard spectrum analyser
display press SPECT
NOTE: Please refer to section 5-3 for specific instructions for step resolution mode operation.
To activate Channel Scope mode, press CHANL In 'channel scope mode', you may view a defined
bandwidth up to a maximum span of 5 MHz minus one step. In particular, channel scope mode is very
useful for viewing relatively narrow bands of a couple of MHz. ONLY the wanted steps are checked for
activity and as a narrower span is specified, screen refresh can be significantly faster than sweeping a
whole 10 MHz bandwidth. To achieve this, the LCD-step is automatically forced to equal the tuning step
of the companion radio.
When channel scope mode is run for the first time, a menu is presented prompting you to input three
values to define operation:
1) Channel Scope Start Freq (MHz)... enter the
required lower band edge frequency using MHz
format then press
2) Channel Scope Step Freq (kHz)... enter the
required channel step using kHz format then press
3) Channel Scope End Freq (MHz)... enter the
required upper band edge frequency using MHz
format then press
Note: The MAXIMUM bandwidth is
5000 kHz (5 MHz) minus one channel step.
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