R&S ZVA8 - Page 411

R&S ZVA Repairs
1177.5333.02 3.103 E-11
Frequency
Output level
Displayed level
ax or bx
300 kHz
-20 dBm
0 dBm
50 MHz
-20 dBm
0 dBm
1 GHz
-20 dBm
0 dBm
3 GHz
-20 dBm
0 dBm
6 GHz
-20 dBm
0 dBm
8 GHz
-20 dBm
0 dBm
With the stated levels, the cable loss must still be taken into account. For the specified cable, it is
0.25 dB/GHz (0.5 m) or. 0.5 dB/GHz (1 m).
If the measured values are more than 3 dB below the levels and ratios list in the table, the board must
be replaced.
Bridge unit levels
The following is assumed:
 One reflectometer in the instrument is OK.
Method 1:
The generator section of the associated reflectometer is OK (output level at the port meets
specifications).
 Loosen cable W515 (Bridge unit -> MEAS) and cable W518 (Bridge unit -> REF) at both ends and
disconnect at the bridge unit.
N.B.: When loosening, support the cable with a 7mm spanner
 Connect the bridge unit output (MEAS = connector W515 or REF = connector W518) to a
functioning port using the SMA cable and adapter SMA-N (measure wave quantity bx). Terminate
the bridge unit output that is not used with an SMA termination.
 Screw the SHORT from a N-calibration kit to the port connector, save measured values (Data ->
Mem).
 Screw the OPEN from the calibration kit to the port connector.
 Select User Def Math : (lin Mag(Data) + (linMag(Mem2)) / 2 , activate Result is Wave Quantity
 Select Math = User Def
 Set the frequencies and levels listed in the table for the reflectometer associated with the bridge
unit (port) and measure the level (wave quantity bx) at the port used for the measurement.
Frequency
Level
Output level MEAS
Output level REF
300 kHz
0 dBm
-18 dBm
-32 dBm
50 MHz
0 dBm
-18 dBm
-32 dBm
1 GHz
0 dBm
-18 dBm
-32 dBm
3 GHz
0 dBm
-18 dBm
-32 dBm
6 GHz
0 dBm
-18 dBm
-32 dBm
8 GHz
0 dBm
-18 dBm
-32 dBm
With the stated levels, the cable loss must still be taken into account. For the specified cable it is
0.25 dB/GHz.
If the measured values are more than 3 dB below the levels in the table, the board must be replaced.