HP 8481A - Adjustments and Calibration; FET Balance Adjustment

HP 8481A/82A/83A
08481-90049
Table 4. SWR and Reflection Coefficient
System SWR Uncertainty
Frequency
Actual
Measurement
Maximum SWR
(Reflection Coefficient)
HP 8481A
10 to 30 MHz
±0.030
< 1.40 (0.166)
< 1.18 (0.083)
< 1.10 (0.048)
< 1.18 (0.083)
< 1.28 (0.123)
30 to 50 MHz
±0.020
50 MHz to 2 GHz
±0.020
2 to 12.4 GHz
±0.020
12.4 to 18 GHz
±0.025
HP 8482A
100 kHz to 300 kHz
±0.08
< 1.60 (0.231)
< 1.20 (0.091)
< 1.10 (0.048)
< 1.30 (0.130)
300 kHz to 1 MHz
±0.04
1 MHz to 2 GHz
±0.02
2 to 4.2 GHz
±0.02
HP 8483A
100 kHz to 600 kHz
±0.08
< 1.80 (0.286)
< 1.18 (0.083)
600 kHz to 2 GHz
±0.02
The FET balance adjustment should be performed if the wires
connecting J1 to the A2 printed circuit have been moved.
If you have
replaced A2 or moved the wires during troubleshooting you will need to
perform this adjustment. You do not need to perform a FET balance
adjustment after an A1 bulkhead assembly replacement if the wires
between J1 and A2 have not been disturbed.
FET Balance
Adjustment
Warning
0
The following procedure exposes high voltage areas
within the power
meter. Use extreme care while working around these
areas or personal
injury could occur.
Equipment
Oscilloscope
Power Meter
Multimeter .
The sampling gate balance is affected by the relative positions of the
wires in the Power Sensor, which connect to pins G and H of connector
Jl. One wire is black and white; and the other is brown and white.
Moving the black and white wire will adjust the switching transient
amplitude (spike). Moving the brown and white will
change the offset.
Once positioned, care must be used not to displace these wires. To
correctly position these wires, after replacement of
the printed circuit
HP 54200A
HP 435B
HP 3478A
7