On the sibilance problem in FM sound transmission

The received sibilant sounds on FM transmission are often distorted because of portions of high amplitude values found in the Gaussian noiselike S's which over-modulate the instantaneous frequency beyond the IF filter band for a moment, and then RF receiver noise is demodulated. Pre-emphasis makes the effect worse. The broadcast peak program meters do not indicate peaks in random signals. Hard limiting after pre-emphasis can relieve the problem.<
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