Tektronix TEKFAX ADA400A, Instruction Manual

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Adjustment Procedures
46
ADA400A Differential Preamplifier
3. Switch the gain setting between 10 and 100 while adjusting RV33 for
minimum shift in the oscilloscope trace.
a.
Make note of trace position at gain setting of 10.
b. Switch gain setting to 100.
c.
Adjust trace to where it was at the gain setting of 10.
d. Repeat steps a to c until there is a minimum amount of shift.
4. Adjust RV32 to center trace on screen.
5. Switch the gain setting from 0.1, 1, 10 and 100 and verify that trace does not
shift more than one division from center.
6. Disconnect setup.
Equipment
Required One digitizing oscilloscope (item 1)
One sine wave generator (item 2)
One dual input coupler (item 6)
One 50
Ω
terminator (item 7)
Two coaxial cables (item 9)
One adjustment tool (item 10)
1. Connect the ADA400A to Channel 1 and make the equipment settings
according to Table 20.
Table 20: Equipment Settings for Attenuator Balance Adjustments
ADA400A Setting
+ Input DC
-- Input Gnd
Gain 1
Upper Bandwidth 100 Hz
Oscilloscope Setting
Vertical gain 1 V/div
Time base 20 ms/div
Trigger Source Ch4
Sine Wave Generator Setting
Output 10 Hz
LF CMRR Adjustments