Agilent Technologies E8247C PSG CW - Manual (Page 125)

Chapter 5 115
Dual Arbitrary Waveform Generator
Using Waveform Clipping
How Peaks Cause Spectral Regrowth
Because of the relative infrequency of high power peaks, a waveform will have a high peak-to-average
power ratio (see
Figure 5-13 ). Because a transmitter’s power amplifier gain is set to provide a specific
average power, high peaks can cause the power amplifier to move toward saturation. This causes
intermodulation distortion, which generates spectral regrowth.
Figure 5-13 Peak-to-Average Power
Spectral regrowth is a range of frequencies that develops on each side of the carrier (similar to sidebands)
and extends into the adjacent frequency bands (see
Figure 5-14 ). Consequently, spectral regrowth interferes
with communication in the adjacent bands. Clipping can provide a solution to this problem.
Figure 5-14 Spectral Regrowth Interfering with Adjacent Band