1142A Probe Control and Power Module
Service
17
Figure 5
A1 Control and Power Module Block Diagram
Front panel screwdriver adjustment Offset Null zeros the dc output
from the probe when the dc input and offset are zero.
For dc Reject, an output from the low- frequency amplifier in the
probe (LFSIG) is used to develop a voltage used to null the dc
component of the input signal. LFSIG is an input to U6, an
inverting amplifier and low- pass filter. Multiplexer U3 selects one
of three capacitors to set a roll- off frequency of 0.05, 0.5, or 5 Hz.
The output of U6 is selected, again by U3, as the input to the offset
amp. When the output of the offset amp is summed into the low
frequency path, the result is cancellation of the dc component of
the input signal. Front panel screwdriver adjustment DC Reject
Gain adjusts the gain of the dc reject circuit.
Summary of Contents for 1142A
Page 1: ...Agilent Technologies Agilent 1142A Probe Control and Power Module User s Guide...
Page 29: ...1142A Probe Control and Power Module Replaceable Parts 29 Figure 7 Schematic 1...
Page 31: ...1142A Probe Control and Power Module Replaceable Parts 31 Figure 9 Schematic 3...
