Performance Verification
Giga-tronics 2500B Series Microwave Signal Generators
Page 104
Operation Manual, Part Number 34737, Rev C, June 30, 2011
Figure 49: Spectral Purity Test Setup
Table 63: Spectral Purity
Spectral Purity
Step
Action
1.
Connect the equipment as shown in Figure 49;
Connect the timebase output from the spectrum analyzer to the EXT REF IN connector on the
rear of the 2500B. See Figure 6 on page 19 for the location of the connector and the electrical
specifications of the external timebase.
Connect the 2500B RF Output to the RF input using coaxial cabling and adapters as necessary.
2.
Allow the equipment to warm up for at least 30 minutes.
3.
Set the 2500B to the lowest frequency listed in the datasheet that the instrument is capable of, and
set the RF amplitude to + 10 dBm or maximum leveled output (whichever is lower).
NOTE:
The maximum leveled output is the 2500B output power just before the UNLEVELED indicator
on the front panel lights.
4.
Press
to turn on the RF output. The RF on/off indicator illuminates blue when the RF
output is active.
5.
Set the spectrum analyzer to view the 2500B output signal. Adjust the analyzer reference level so
that the peak of the displayed signal is at the top graticule line.
6.
Set the spectrum analyzer span to 500 MHz with the signal centered on the screen. Gradually narrow
the span, keeping the signal centered, to observe any non-harmonically-related or spurious signals.
Note the following;
Use appropriate resolution and video bandwidths to allow sufficient dynamic range.
Adjust the center frequency of the spectrum analyzer to the harmonic and sub-harmonic
frequencies of the test frequency.
7.
Record the levels of the worst case harmonic, non-harmonic or spurious signals in the appropriate
columns of the datasheet.
8.
Repeat steps 5 through 7 for the other frequencies listed in the datasheet that are within the
operating range of the instrument. For frequencies that are outside the range of the model of 2500B
you are testing, enter “N/A” in the datasheet.
RF ON
