Fluke 5790A Service Manual page 112

5790A
Service Manual
3-32
5700A CALIBRATOR
WIDEBAND
OUTPUT
Figure 3-12. Gain Calibration Setup for 70 mV and Above
7. Use the number keys to enter the value displayed on the 8506A DMM into the
5790A, then press [ENTER].
8. The 5790A will calibrate the 7 V range and proceed to the 2.2 V range.
9. Apply 2.0 V at 1 kHz and press "DO STEP" as before.
10. Enter the value from the 8506A into the 5790A as before and press [ENTER].
11. The 5790A will calibrate the 2.2 V range and step to the 700 mV range.
12. The 700 mV, 220 mV, and 70 mV ranges are done in a similar way; just enter the
exact value of the voltage as requested for each range and press [ENTER].
13. Disconnect the 8506A DMM after calibration of the 70 mV range. It is not
accurate enough to calibrate the lower three ranges and it adds noise to the
system.
14. If an accurate millivolt AC source is available, use it to calibrate the 22 mV,
7 mV, and 2.2 mV ranges in the same manner as the other ranges. Just enter the
exact value when requested by the display and press [ENTER].
15. If an accurate millivolt source is not available, use a bootstrapping technique.
Record the 5790A reading on the range above the one to be calibrated, and enter
the recorded value as the "EXACT VALUE" when the display asks for it.
16. To calibrate the 22 mV range, connect the equipment as shown in Figure 3-11.
Apply 20 mV at 1 kHz when the display asks for it (The 5700A will need to be
set to about 600 mV due to the 30 dB of attenuation).
17. Press the 70 mV range key and measure and record the value.
18. Press the "DO STEP" softkey and enter the number just measured on the 70 mV
range. Now press the [ENTER] key and the 5790A will calibrate the 22 mV
range and step to the 7 mV calibration display.
19. Calibrate the 7 mV range by applying 6 mV at 1 kHz and then pressing the
22 mV range key to measure and record the value. Press the "DO STEP" softkey
and enter the value just measured on the 22 mV range. Press the [ENTER] key
HP 3458A
DISCONNECT
DMM CABLE
AFTER 70 mV
RANGE CAL
TYPE 'N' TEE
5790A
AC MEASUREMENT
STANDARD
WIDEBAND
INPUT
elu037.eps