Agilent Technologies PSA Series Service Manual page 60

Overall Troubleshooting
Troubleshooting Using Front Panel Keys
ADC Ctrl
To view the dither signal, go to Basic mode, and set the span to 10 MHz.
- Turns dither on and off.
ADC Dither
- Moves the dither center frequency in the IF. The
ADC Dither CF
default is 11.25 MHz relative to 7.5 MHz (center of the screen). The
DAC range is 1 to 255.
ADC Offset (7, 3, 2, 1, 0)
NONE/direct ADC path or the manual gain path in the following
amounts:
offset adjustment on the NONE/direct ADC path
ADC Offset 7
offset adjustment on the 0 dB manual gain path
ADC Offset 3
offset adjustment on the 6 dB manual gain path
ADC Offset 2
offset adjustment on the 12 dB manual gain path
ADC Offset 1
offset adjustment on the 18 dB manual gain path
ADC Offset 0
(max gain)
These adjustments have a DAC range of 0 to 255. ADC Offset
adjustments are designed for factory use.
ADC Range
- The instrument automatically selects the proper ADC range
Auto
based on the ranging rules in firmware.
- Allows the instrument to range up during a
Auto Peak
measurement but not range down. Allows the ADC range to
automatically change to limit ADC gain (to prevent overdriving the
ADC). The ADC range cannot automatically change to allow more
ADC gain.
- Locks in one range setting. During a measurement
Auto Peak Lock
the ADC will not change ranges. ADC overloads could occur more
easily in this mode, but the fact that the ADC range is unchanged
improves the accuracy.
- Allows front panel control of the Auto range selections:
Manual
None, 0 dB, +6 dB, +12 dB, and +18 dB. The None setting bypasses
the ADC range circuits. When the ADC range is changed, the noise
floor level will increase with decreasing ADC gain values.
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- Provides an offset adjustment on the
Chapter 2