Chapter 2 135
Adjustment Procedures: HP 3335A Source not Available
4a. IF Amplitude Adjustments
Figure 2a-2 IF Amplitude Adjustment Locations
A4 Log Amp/Cal Oscillator Amplitude Adjustment
This adjustment sets the output amplitude of the cal oscillator on the
A4 assembly, and the absolute amplitude of the reference 15 dB
attenuator.
The output of the cal oscillator is adjusted so that a −55 dBm signal
applied to the 10.7 MHz IF input on the A5 IF assembly (A5J3) causes a
displayed signal of −60 dBm. The effect of this adjustment is visible
only after the
ADJ CURR IF STATE sequence is complete.
ADJ CURR IF STATE causes the IF gain adjustment to use the “new”
output amplitude from the cal oscillator. When the adjustment
sequence is complete, the result of the adjustment should cause the
−35 dBm signal at A5J5 to be displayed at −60 dBm.
This procedure also sets the attenuator of the reference 15 dB
attenuator so that a source amplitude change of 50 dB combined with a
spectrum analyzer reference level change of 50 dB displays an
amplitude difference of 50 dB.
NOTE The 15 dB reference attenuator adjustment is preset at the factory and
need not be done if the entire A5 IF assembly is replaced.
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