Rohde & Schwarz ZVB 14, Service Manual

Page: 15 / 198

R&S ZVB Performance Test
1145.1078.82 1.5 E–4
Checking the Harmonics
Instrument:
Spectrum analyzer (see Chapter "Test Equipment", Item1)
Test cable (see Chapter “Test Equipment", Item7)
Test setup: Connect the spectrum analyzer to port1 (port 2 to port 4)
Spectrum analyzer settings:
Note:
Synchronize the reference oscillators in the spectrum analyzer and in the
R&S
®
ZVB.
– [
PRESET ]
– [ FREQ : f
GEN
, 2* f
GEN
, 3* f
GEN
*]
– [ SPAN : ZERO SPAN ]
– [ BW : MANUAL RES BW : 100 Hz ]
– [ MARKER : DETECTOR : RMS ]
– [ AMPT : REF LEVEL : 10 dBm ]
* For measurement frequencies, see Performance Test Report {fGEN}.
R&S ZVB settings:
– [ Preset ]
– [ Meas : Wave Quantities: a1 Src Port 1
(a2 Src Port 2, a3 Src Port 3, a4 Src Port 4)]
– [ Sweep : Sweep Type : CW Mode :
CW Frequency : {f
GEN
*} ; Power : 8 dBm ]
– [ Sweep : Single : Restart ]
* For measurement frequencies, see Performance Test Report {fGEN}.
Measurement: Read off the levels L
n*fgen
(n = 1, 2, 3) indicated by the spectrum
analyzer’s markers.
Calculation:
Harmonics =
L
n*
f gen
– L
fgen
– cable loss
(in dB)
The cable loss corresponds to the S
21
of the test cable used between the
fundamental and the measured harmonic (S
21
is negative).