If Amplitude Adjustment Locations - HP 8560A Service Manual

4. IF Amplitude Adjustments
J 4 '
A4 Log Amp/Cal Oscillator Amplitude Adjustment
This adjustment sets the output amplitude of the A4 Log Amp/Cal Oscillator and the
absolute amplitude of the reference 15 dB attenuator.
The output of the A4 Log Amp/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.
output amplitude from the A4 Log Amp/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.
2-26 Adjustment Procedures
A5 IF
( R E
C O N N E C T O R )
Figure 2-7. IF Amplitude Adjustment Locations
causes the IF gain adjustment to use the "new"
A 4 L O G A M P
R 4 4 5
V I S I O N
R 5 3 1 '
ADJ CURR IF STATE
J 7
R 8 2 6
J 5
J 4
R 5 4 4
J 3