HP 85020A Operating And Service Manual page 36

Performance Tests
Model 85020A/B
Equipment (continued)
For Use with 85020A (50-Ohm)
50-Ohm Type-N Short . HP 11512A
50-Ohm Shielded Open . HP 85032-60001
50-Ohm Termination .. HP Q09A Opt. 012
For Use with 85020B (75-Ohm)
50-Ohm to 75-Ohm Minimum Loss Pad ....
75-Ohm Tyoe-N Short .
75-Ohm termination .
CAUTION
Do not mix 50-ohm and 75-ohm hardware, as
this may damage the connectors.
HP 11852A
HP 1250-1530
HP 1250-1532
Procedures
1. Set up the eauipment as shown in Figure 4-3, with the
appropriate calibrated short connected to the Directional
Bridge (the test device, not the device under test). If the
Directional Bridge is an 85020B, connect the Model 11852A
50-ohm to 75-ohm minimum loss pad between the output of the RF
Plug-In and the inout port of the Directional Bridge.
2. Set up the test equipment as follows:
On the Sweep Oscillator, press
[INSTR PRESET] [SWEEP TIME] [1]
[5] [0] [ms]
ELTI
MOD]
. On the Scalar Network Analvzer, press
[PRESET]
, then turn off Channel 2 bv pressing
[SHIFT]
and
Channel 2
[MEAS RATIO].
3. On the 8350A/B Sweep Oscillator, set the START and stop
frequencies to correspond to the first band of freauencies in
the Performance Test Record (0.01 to 1.3 GHz).
4. Perform an open/short calibration using the correct eauipment
listed above for the respective Directional Bridqes. For OPEN
calibration of the 85020B, leave the test port unterminated.
5. Connect the Directional Bridge under test to the first
Directional Bridge, TEST port to TEST port, using an adapter.
Leave the cable of the Directional Bridge under test
unconnected. Connect a matched load to the input port of the
Directional Bridae under test.
6. On the 8756A, press
[SHIFT] [SCALE]
for the AUTOSCALE
function, then press
[CURSOR] [CURSOR MAX 1]
to find the point
of minimum return loss (the high point on the trace). Use the
reflectometer calculator to convert this measured return loss
4-6