Video Processor Adjustments; Video Processor Adjustments Setup - HP 8566B Adjustment Manual

IF-Display Section
Log Scale Switching Uncertainty Test
The CAL OUTPUT signal is connected to the RF INPUT through a
step attenuator. The instrument is placed in zero frequency span to
produce a dc level output from the log amplifier. The A4A2R79 ZERO
adjustment, which sets the dc offset of the output buffer amplifier of
the log board, is checked and adjusted if necessary. The dc level into
the video processor is is adjusted by'varying the input signal level and
reference level. The offsets and gains on the A4Al Video Processor
are adjusted for proper levels using a DVM.
Figure 3-35. Video Processor Adjustments Setup
Digital Voltmeter (DVM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HP 3456A
10 dB Step Attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .HP 355D
The voltage at A4AlTP3 may drift noticeably with temperature
during this adjustment. Allow the A4Al Video Processor to warm up
at least one-half hour prior to adjustment.
Position the spectrum analyzer upright as shown in Figure 3-35.
Remove the IF-Display Section top cover.
2.
Set the spectrum analyzer LINE switch to ON and press @YXiGJ
3.
Connect DVM to A4AlTPl and DVM ground to
4.
Connect CAL OUTPUT to RF INPUT through 10 dB step
attenuator.
5.
[
Key in
CENTER FREQUENCY
Press the LIN pushbutton.

6. Video Processor Adjustments

the
] [
100 MHz and
FREQUENCY SPAN
IF casting.
)
0 Hz.
Adjustments 3-73