HP 85020A Operating And Service Manual page 32

Performance Tests Model 85020A/B
4-7. DIRECTIVITY
Specifications:
85020A 85020B
0.01 to 2.4 GHz >40 dB >40 dB
2.4 to 3.0 GHz >40 dB
-
3.0 to 4.3 GHz >34 dB
—
Description:
Directivity is a measure of the ability of a directive device to
discriminate between incident and reflected signals. In principle,
directivity can be measured when the TEST port is terminated with
a perfect load to eliminate all reflected sianals. Anv remaining
signals detected are the directivity errors. However, since no
perfect load is available, the test procedures below make
allowances for this external error.
First an open-short calibration is performed. Then a fixed load
(termination) with the best possible return loss is connected to
the TEST port, and the new measured value is recorded.
Equipment:
Sweep Oscillator . HP 8350A/R
RF Plug-In .... . HP 83522A/83525A/B
Scalar Network Analyzer .. HP 8756A
For Use with 85G20A (50-Ohm)
50-Ohm Type-N Short . HP 11512A
50-Ohm Shielded Open . HP 85032-60001
50-Ohm Termination . HP 909A Opt. 012
For Use with 85020B (75-Ohm)
50-Ohm to 75-Ohm Minimum Loss Pad. HP 11852A
75-Ohm Tvpe-N Short ... . HP 1250-1530
75-Ohm Termination . HP 1250-1532
CAUTION
Do not mix 50-ohm and 75-ohm hardware, as
this may damage the connectors.
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