HP 8568B, Performance Tests And Adjustments Manual, Page: 218 / 313

13. 20 MHz Reference Adjustments
Procedure
1. Position instrument on right side as shown in Figure 3-56 and
remove bottom cover. Remove 20 MHz Reference and install
on extenders. See Figure 3-57 for the location of components.
2. Set LINE switch to ON and press
PRESET
).
3. Set rear-panel FREQ REFERENCE INT/EXT switch to INT.
Disconnect cable 2 (red) from Connect power meter to
output of Time Base using cable 2 (red). Note power
meter indication for reference later.
4. Reconnect Time Base output to
5. to Ground. Set the HP Spectrum
Analyzer to
[
CENTER FREQUENCY
)
20
MHz,
SPAN
)
1 MHz,
LEVEL
)
and 100 Connect
to RF INPUT of HP Analyzer and set
[
REFERE
N
CE
to place of signal at reference line (top graticule
line).
6. Set HP Spectrum Analyzer to 1 dB/division SCALE and
reset reference level to place peak of signal at reference line.
7. Connect DVM to and ground to Adjust
COMB DRIVE for DVM indication of + 0.1 V dc.
Disconnect DVM. (If DVM remains connected, it may load circuit.)
See Figure 3-57 for location of adjustment.
R E F E R E N C E
Figure 3-57. Location of 20 MHz Reference Adjustments
8. Adjust DOUBLER to lower signal peak approximately
3 Adjust CENTER FREQ to peak signal on HP
Spectrum Analyzer display. Next, adjust DOUBLER
for signal peak.
9. Disconnect cable 2 (red) from and connect OUTPUT of
frequency synthesizer to Set FREQUENCY of frequency
synthesizer to 10.17 MHz and set AMPLITUDE to + 3 Set HP
3-104 Adjustments