Rohde & Schwarz R&S SMU200A, Service Manual

Page: 39 / 294

Test Procedures R&S SMU200A
1007.9845.82 1.12
E-12
Spectral Purity
Harmonics
Test equipment Spectrum analyzer (Table 1-2, item 24)
Test setup Connect the spectrum analyzer to the RF output of the DUT.
Synchronize reference frequencies of analyzer and DUT.
Recommended settings on the
spectrum analyzer
Reference level = test level + 3 dB, 10 dB/div.
Span 0 Hz,
Resolution bandwidth 1 kHz,
Video bandwidth 30 Hz,
Sample detector
Note:
These values are typical values that depend on the analyzer used.
The necessary measurement resolution must be verified prior to the measurement.
Recommended frequencies
According to Table 1-4
Measurement Settings on DUT:
- Frequency: test frequencies, unmodulated
- Level: level
max
according to data sheet (depending on
configuration of the unit)
First measure the level of the fundamental as a reference. Then find
signals at twice and three times the carrier frequency.
The harmonic spacing is the measured level referred to the
fundamental (dBc = referred to the carrier).
Subharmonics
Test equipment Same as for harmonics suppression
Test setup Same as for harmonics suppression
Recommended frequencies 1501 MHz, 1550 MHz to 6000 MHz in 50 MHz steps
Measurement
First the level of the fundamental is measured as reference, then a
signal is searched for at 0.5*test frequency and 1.5*test frequency.
The subharmonic spacing is the measured level referred to the
reference level (dBc = referred to the carrier).