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Keysight EXG and MXG X-Series Signal Generators User’s Guide
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Basic Digital Operation (Option 653/655/656/657)
Clipping a Waveform
How Peaks Cause Spectral Regrowth
In a waveform, high power peaks that occur infrequently cause the waveform to have a high peak–
to–average power ratio, as illustrated in the following figure.
Because the gain of a transmitter’s power amplifier is set to provide a specific average power, high
peaks can cause the power amplifier to move toward saturation. This causes the intermodulation
distortion that generates spectral regrowth. 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 the following figure). Clipping provides a solution to this problem by reducing the peak–
to–average power ratio.