User`s guide

198 Chapter 9
Tw o -To n e Wav e fo rm Ge ne r at or
Creating, Viewing, and Modifying Two-Tone Waveforms
Figure 9-3
To Minimize Carrier Feedthrough
This procedure describes how to minimize carrier feedthrough and measure the difference in power
between the tones and their intermodulation distortion products. Carrier feedthrough only occurs
with center- aligned two- tone waveforms.
This procedure builds upon the previous procedure.
1. On the spectrum analyzer, set the resolution bandwidth for a sweep rate of about
100- 200 ms. This will allow you to dynamically view the carrier feedthrough spike as you make
adjustments.
2. On the signal generator, press
I/Q > I/Q Adjustments > I/Q Adjustments Off On to On.
3. Press
I Offset and turn the rotary knob while observing the carrier feedthrough with the spectrum
analyzer. Changing the I offset in the proper direction will reduce the feedthrough level. Adjust
the level as low as possible.
4. Press
Q Offset and turn the rotary knob to further reduce the carrier feedthrough level.
5. Repeat steps 3 and 4 until you have reached the lowest possible carrier feedthrough level.
Carrier
Feedthrough
Intermodulation
Distortion
Two-Tone
Channels
Carrier Feedthrough
Distortion