Agilent Technologies 1141A Thermometer User Manual


 
38
Calibration Tests and Adjustment
CMRR Test
15 Connect the input of the probe to the test board in the position shown in the
figure below (signal to + input).
Figure 2-11
Signal to + input
16 Set the signal generator for 100 MHz at 0.0 dBm (about 224 mV
rms
, 632 mV
p-p
).
17 Set the oscilloscope to channel 1 and change the horizontal scale to 5 ns/div.
18 After the measurement settles (averaging is complete), note the V P-P reading.
V
p-p
(1) = _____________ mV
19 Connect the input of the probe to the test board in the position shown in the
figure below (signal to both inputs).
Figure 2-12
Signal to both input
20 Set the channel 1 sensitivity to 10 mV/div.
21 After the measurement settles (averaging is complete), not the V P-P reading.
V
p-p
(2) = _____________ mV
22 Disconnect the probe amp from the test board and measure V
noise pp
on
channel 1.
23 Calculate the CMRR result as follows
24 The result in step 21 should be 10, representing a CMRR of 10:1 or more.
Record the CMRR in the Calibration Test Record.
CMRR
V
pp
1
V
pp
2
V
noisepp
-------------------------------------=