Operating the Probe
1
To Adjust Offset Null and DC Reject Gain
1141A and 1142A User’s Guide
13
To Adjust Offset Null and DC Reject Gain
For a given combination of 1141A Differential Probe and 1142A
Probe Control and Power Module, you can adjust the Offset Null
and DC Reject Gain. Typically, you need to make these adjustments
only once, before the probe is first used. You can make them any
time to optimize the system. These adjustments do not affect the
specifications of the probe system.
■
Offset null zeros the dc level at the output of the probe. The range
of adjustment is about ±4 mV.
■
DC Reject Gain adjusts the gain of the dc reject circuit to
accurately null the dc component of an input signal. The range of
adjustment is about ±0.5%.
Figure 4
1142A Front Panel
Equipment Needed
The following equipment is necessary for initial adjustment.
■
5V power supply
■
DVM that can measure 25 µV
■
50
Ω
BNC feed- through terminator
■
01141- 66504 test board
CAUTION
Do not exceed ±7V when using the test board for this procedure. If the voltage is
too high, it will cause excessive power dissipation in the 50
Ω
termination on the
test board.
1
Perform the steps in
2
Connect a 50
Ω
BNC feed- through terminator to the output of the
probe.
3
Disconnect all accessories from the input of the probe.
Summary of Contents for 1141A
Page 4: ...4 1141A and 1142A User s Guide Contents...
Page 58: ...58 1141A and 1142A User s Guide 3 Adjusting the Probe Attenuator Adapter Adjustment...
Page 76: ...76 1141A and 1142A User s Guide 4 Service Replaceable Parts Figure 44 Cabling Diagram...
Page 86: ...86 1141A and 1142A User s Guide 4 Service Replaceable Parts...
