HP 8568B, Руководство по испытаниям и регулировке работы, Страница: 255 / 313

23. Analog-To-Digital Converter Adjustments
1. Adjust GAIN for a square wave displayed on the
oscilloscope. The square wave should be approximately 4
See Figure 3-86 for location of adjustment.
Alternate Procedure
4. Procedure without using Low-Noise DC Supply:
a. Press
b. Key in TRACE A and SWEEP (SINGLE).
c. Disconnect cable 0 (black) from sweep ramp input
d. Short to or connect SMB snap-on short to
e. Connect DVM to and ground to Set DVM
for V ac.
f. Adjust OFFS until
the
level at is at a
maximum ac voltage as indicated by the DVM (approximately
2.0 V ac). See Figure 3-86 for location of adjustment.
g. Remove short from and Reconnect cable 0
(black) to 1.
h. Press
PRESET
].
i. Connect DVM to and ground to Set DVM
for V dc.
j. Press SWEEP Note DVM reading at end of the sweep.
The voltage will begin to drift immediately after the sweep
ends. Therefore, the first indication after the sweep ends is the
valid indication. It may be helpful to press
several times
to ensure a valid indication at the end of the sweep.
k. If DVM indication is 10.020 V dc at
the
end of the
sweep, no further adjustment is necessary. Otherwise, adjust
GAIN and repeat step j until the voltage at the end of
the sweep is + 10.020 V dc.
Adjustments 3-141