R&S ZVA8, Service Manual

Page: 426 / 606

Repairs R&S ZVA
1177.5333.02 3.118 E-11
Frequency Level level ax and bx
10 MHz 0 dBm > -2 dBm
100 MHz 0 dBm > -2 dBm
1 GHz 0 dBm > -2 dBm
3 GHz 0 dBm > -2.1 dBm
8 GHz 0 dBm > -2.3 dBm
10 GHz 0 dBm > -2.4 dBm
12 GHz 0 dBm > -2.5 dBm
15 GHz 0 dBm > -2.6 dBm
18 GHz 0 dBm > -2.7 dBm
20 GHz 0 dBm > -2.8 dBm
25 GHz 0 dBm > -3 dBm
30 GHz 0 dBm > -3.2 dBm
35 GHz 0 dBm > -3.4 dBm
40 GHz 0 dBm > -3.6 dBm
45 GHz 0 dBm > -3.8 dBm
50 GHz 0 dBm > -4 dBm
55 GHz 0 dBm > -4.2 dBm
60 GHz 0 dBm > -4.4 dBm
67 GHz 0 dBm > -4.7 dBm
With the stated levels, the cable loss must still be taken into account.
If the measured values are more than 2 dB below the levels given in the table, the coupler unit must be
replaced.
Coupler Directivity
The following is assumed:

The generator and receiver sections of the reflectometer associated with the coupler are OK.

Perform a sweep from 10 MHz to 67 GHz, measure Ratio bx/ax Source Portx

Screw the SHORT from the calibration kit to the port connector, save measured values (Data ->
Mem).

Screw the OPEN from the calibration kit to the port connector, save measured values (More Mem :
Data -> Mem3).

Screw the MATCH from the calibration kit to the port connector.

Select User Def Math : linMag(Data) / (linMag(Mem2) + linMag(Mem3)) / 2 : Math = User Def

The trace gives the directivity.
Frequency range Directivity
10 MHz to 20 GHz < -14 dB
20 GHz to 35 GHz < -10 dB
35 GHz to 40 GHz < -8 dB
40 GHz to 50 GHz < -6 dB
50 GHz to 67 GHz < -3 dB
If the measured values are more than 2 dB greater than the values stated in the table, the coupler must
be replaced.