Offset (Final); Dc Cmrr - Tektronix P6248 Service Manual

Offset (Final)

DC CMRR

P6248 1.7 GHz Differential Probe Service Manual
5. Adjust the power supply to output about 700 mV.
÷
6. Adjust the 1 gain adjustment until the output voltage measures the same as
±
the input within 5 mV.
7. Change the probe attenuation to
8. Change the DMM monitoring the input to the 20 or 30 volt range.
9. Adjust the power supply to output approximately 7 V.
÷
10. Adjust the 10 gain adjustment until the DMM measuring the output reads
1/10 of the same voltage as the DMM monitoring the input within
11. Keep the probe output connections for the next step.
NOTE. The offset and gain adjustments interact.
1. Repeat steps 1 through 6 of the Offset (preliminary) procedure.
2. Remove the output cable termination and input for the next procedure.
1. Set up the equipment as shown in Figure 12:
a. Connect a BNC cable from the output of the 1103 to the Channel 1 input
of the oscilloscope. If the oscilloscope does not have 50 Ω input setting,
add a 50 Ω inline BNC terminator at the oscilloscope input.
b. Connect the Y lead adapter to the probe input. Using square pins,
connect both leads to the red binding post of a binding post to BNC
adapter. Connect the BNC adapter to the function generator output. (If
necessary, use a BNC cable and a female-to-female BNC connector
between the BNC adapter and the generator.) If the function generator
reference (shield of the BNC connector) is isolated from ground, connect
the ground lead from the probe case to the black binding post.
NOTE. Do not use the BNC to probe tip adapter for this connection. The power
level of the generator will exceed the terminator rating.
Adjustment Procedures
÷
10.
±
5 mV.
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