HP 8568B manual Filter Peak Adjust, Key in Csweep Time 20 ms, Frequency Span 0 Hz, CREs 10 Hz

7.3 MHz Bandwidth Filter Adjustments

10.Adjust A4A7C15 CTR for minimum amplitude of signal peak. Adjust A4A7C14 SYM for best symmetry. Repeat adjustments to ensure that the signal is nulled and adjusted for best symmetry. See Figure 3-38 for location of adjustments.

11.Remove crystal filter bypass network near C23 SYM.

12.Adjust A4A7C24 CTR for minimum amplitude of signal peak. Adjust A4A7C23 SYM for best symmetry of signal. Repeat adjustments to ensure that signal is nulled and adjusted for best symmetry. See Figure 3-38 for location of adjustments.

13.Remove crystal filter bypass network near C32 SYM.

14.Adjust A4A7C33 CTR for minimum amplitude of signal peak. Adjust A4A7C32 SYM for best symmetry of signal. Repeat adjustments to ensure that signal is nulled and adjusted for best symmetry. See Figure 3-38 for location of adjustments.

15.Remove crystal filter bypass network near C41 SYM.

16.Adjust A4A7C42 CTR for minimum amplitude of signal peak. Adjust A4A7C41 SYM for best symmetry of signal. Repeat adjustments to ensure that the signal is nulled and adjusted for best symmetry. See Figure 3-38 for location of adjustments.

17.Signal should be centered on center graticule line on CRT display. If signal is not centered, go back to step 3 and repeat adjustments of each filter stage.

Filter Peak Adjust

18.Press (JNSTR PRESET].

19.Key in CSWEEP TIME] 20 ms, [FREQUENCY SPAN) 0 Hz, CREs] 10 Hz,

[ R E F E R E N C E L E V E L )-20 dBm.

20.Set the frequency synthesizer for 21.400 MHz at an amplitude level of -25.0 dBm.

21.Disconnect cable 97 (white/violet) from A4A8Jl and connect output of the frequency synthesizer to A4A8Jl using BNC to SMB snap-on cable.

22.Set the oscilloscope following settings:

Channel 1

amplitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.005 V/div time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...0.2 psldiv mag x . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 (vertical) . coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..ac probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1O:l

Channel 2

amplitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O.O05V/div coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ac probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1O:l

23.Connect oscilloscope Channel 1 probe to A4A7TP7 (left side of Cl4 SYM) and Channel B probe to A4A7TP5 (left side of C23 SYM).

24.Adjust frequency synthesizer output frequency to peak Channel 1 display.

3-74 Adjustments