Chapter 10 235
Two–Tone Waveform Generator
Creating, Viewing, and Modifying Two–Tone Waveforms
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 Figure 10- 4. 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 10-4
To Change 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 eliminates 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.
Minimized
Delta Marker
Main Marker
Carrier
Feedthrough
To Next Page
Loading...
Need help?
General
