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5790A
Service Manual
3-30
COMPUTER
TERMINAL
(FOR SERVICE
CAL ONLY)
RS-232
5700A CALIBRATOR
WIDEBAND
OUTPUT
Figure 3-10. Wideband Calibration Source Characterization, Part 1
2. Make sure equipment warmup requirements are met.
3. Lock the 5790A on the 220 mV range.
4. Set the 5700A to output 3.2 V at 1 kHz. The 5790A will read approximately
100 mV, and the 3 V A55 output will be about 7 mV.
5. Allow the A55 to stabilize, then press the STORE and OFFSET keys on the
8506A DMM.
6. Press the "SET REF" softkey on the 5790A.
7. For each frequency in Table 3-8, set the 5700A frequency and perform steps 8, 9,
and 10.
8. Apply any corrections for the response of the A55 TVC by first adjusting the
5700A output to bring the 8506A DMM offset reading to 0 3 counts, and then
pressing the "NEW REF" key on the 5700A, and then further adjusting the
5700A to give the same error and sign as recorded on the A55 calibration sheet
when it was calibrated. Also record the A55 correction in Table 3-8.
9. Record the error showing on the 5790A Control Display, including polarity, in
Table 3-8.
10. Return to 3.2 V at 1 kHz after each frequency calibrated to verify that the 8506A
is still reading 0. Rezero the 8506A if necessary by pressing the OFFSET,
STORE, and OFFSET keys again. The 5790A display should read 0 20 ppm. If
it does not, press the "CLR REF WBND" softkey followed by "SET REF"
softkey to rezero.
11. Set the 5700A to STANDBY.
12. Remove the DMM, A55, and the TEE, and connect the 5700A wideband cable to
the attenuator input as shown in Figure 3-11.
8506A DMM
3V
A55
20 dB
10 dB
GR374 T
ATTEN
ATTEN
NO CABLES
5790A
WIDEBAND
INPUT
elu035.eps
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