R&S SM300
Manual Test Procedure
Version 04
75
Service Manual SM300: 1147.1652.00
Instrument Part No SM300: 1147.1498.03
2.4.5 Spectral Purity
2.4.5.1 Harmonic Suppression
Test setup
Test setup 1 with spectrum analyzer
Settings on SM300
LEVEL 10 dBm (or max. level according to data sheet)
Frequencies: 10 kHz, 100 kHz, 1MHz, 10 MHz, 100 MHz, 300 MHz,
400 MHz, 500 MHz, 1000 MHz, 1200 MHz, 3000 MHz
Setting on spectrum
analyzer
Reference level = test level+10 dB, 10 dB/div
Span 300 kHz, resolution 30 kHz
Measurement
First measure the fundamental level as reference, then search signals
at twice or three times the carrier frequency. Make sure that spectrum
analyzer is not overdriven.
Evaluation
The harmonic suppression is the level difference between the measured
harmonic and the SM300 output signal (in dBc, with reference to the
carrier).
2.4.5.2 Nonharmonics Suppression
Test setup
Test setup 1 with spectrum analyzer
Settings on SM300
Level 10 dBm
Frequencies: any
Note
The values for setting the spectrum analyzer are reference values and
depend on the analyzer used. The required settings have to be verified prior
to each measurement.
2.4.5.3 SSB Phase Noise
Test setup
Test setup 2
Settings on SM300
REF to external
LEVEL 0 dBm (or level to mixer specification)
FREQUENCY 1 GHz
Test method 2
(preferred)
Test method 1
You can use as an alternative the normal Phase Noise measurement
functionality of the spectrum analyzer FSEA30 (Table 2-1, item 2)
The two signal generators are set to the test frequency and synchronized with
a phase shift of 90° (phase quadrature). The RF carrier is suppressed by
mixing to 0 Hz. Due to the phase quadrature the mixer supplies a voltage that
corresponds to the phase difference between the input signals. The phase
difference is measured by the spectrum analyzer and can be converted into
SSB phase noise.
