Giga-tronics Series 12000A, Operation Manual

Page: 208 / 238

Series 12000A Microwave Synthesizers
4-6 Publication 31231, Rev. J, October 2003
4.2.4 Single Sideband Phase Noise
4.2.4.1 Description
The test in this procedure is limited by the measuring system and verifies only the majority of the phase
noise specification. To completely test the phase noise specification requires a far more sophisticated
measurement system. This test uses the spectrum analyzer to make all measurements from 100 Hz to
1 MHz offsets. The 100 Hz and 1 MHz offsets are particularly susceptible to measurement system
limitations.
4.2.4.2 Equipment Required
UUT
²
Spectrum Analyzer
²
Coaxial Cable
4.2.4.3 Procedure
1. Connect the 12000A RF output to the spectrum analyzer input. Place the 12000A on a foam
pad to isolate it from any external mechanical vibrations, which could affect the phase noise
measurement.
2. Turn off all modulation on the 12000A.
3. For the first frequency on the test data sheet within the range of the instrument, press
[CW]
and
enter the frequency. Tune the spectrum analyzer to the generator frequency and adjust the
12000A RF level to obtain a reference of 0 dBm on the analyzer. This allows direct
measurement of the phase noise by the analyzer.
4. Set the analyzer span such that the desired offset is at
±
2 divisions, select an appropriate
bandwidth, activate the phase noise measurement and place the marker two divisions to the
right of the carrier. Read the phase noise in dBc/Hz. Repeat for all offsets.
5. Repeat steps 3 and 4 for the other test data sheet frequencies which are within range of the
12000A.
Figure 4-3: Single Sideband Phase Noise