HP 8568B, Performance Tests And Adjustments Manual, Page: 254 / 313

23. Analog-To-Digital Converter Adjustments
Procedure
1. Position instrument upright as shown in Figure 3-85 and remove
top cover.
2. Set LINE switch to ON and press
PRESET
).
Standard Procedure
3. Procedure using Low-Noise DC Supply is illustrated in Figure 3-93.
a. Key in TRACE A and SWEEP
b. Disconnect cable 0 (black) from sweep ramp input
c. Short to or connect SMB snap-on short to
1.
d. Connect the oscilloscope’s probe to and ground
the probe’s ground to the section’s card cage.
e. Set the oscilloscope settings as follows:
amplitude scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . 0.1
time scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
f. Adjust OFFS for a square wave displayed on the
oscilloscope. The square wave should be approximately 4 V
p-p
.
See Figure 3-86 for location of adjustment.
A N A L O G - T O - D I G I T A L C O N V E R T E R
( B e n e a t h C o v e r )
G A I N O F F S
Figure 3-86.
Location of Analog-To-Digital Converter Adjustments
g. Remove short from and or disconnect the
SMB snap-on short from
h. Press
PRESET
).
i. Press MARKER 1498 (MHz), and
j. Connect DVM to and ground to Set DVM
for V
k. Connect output of the Low-Noise DC Supply to Adjust
the Low-Noise DC Supply for DVM indication of + 10.000
dc.
Adjustments