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Keysight EXG and MXG X-Series Signal Generators User’s Guide
Multitone and Two-Tone Waveforms (Option 430)
Using Two–Tone Modulation
5.
Repeat steps 3 and 4 until you have reached the lowest possible carrier feedthrough level.
6.
On the spectrum analyzer, return the resolution bandwidth to its previous setting.
7.
Turn on waveform averaging.
8.
Create a marker and place it on the peak of one of the two tones.
9.
Create a delta marker and place it on the peak of the adjacent intermodulation product, which
should be spaced 10 MHz from the marked tone.
10.
Measure the power difference between the tone and its distortion product.
You should now see a display that is similar to the one shown in
. Your
optimized two–tone signal can now be used to measure the IMD products generated by a device–
under–test.
Note that carrier feedthrough changes with time and temperature. Therefore, you will need to
periodically readjust your I and Q offsets to keep your signal optimized.
Figure 17-3
Changing the Alignment of a Two–Tone Waveform
This procedure describes how to align a two–tone waveform left or right, relative to the center
carrier frequency. Because the frequency of one of the tones is the same as the carrier frequency,
this alignment typically hides any carrier feedthrough. However, image frequency interference
caused by left or right alignment may cause minor distortion of the two–tone signal. This procedure
builds upon the previous procedure.
1.
On the signal generator, press
Mode
>
Two Tone
>
Alignment Left Cent Right
to Left.
2.
Press
Apply Settings
to regenerate the waveform.
Main Marker
Delta Marker
Minimized
Carrier
Feedthrough
For details on each
key, use key help as
described on
