Features of modulation of sound by sound in grainy medium

摘要

Results of a laboratory experiment on observing amplitude modulation of low-frequency wave propagating in dry river sand caused by an intensive amplitude-modulated high-frequency signal are discussd. Oscillograms and spectra of acoustic signals are presented. The observed phenomenon is explained by parametrical modulation of a weak low-frequency signal caused by changes of medium parameters affected by amplitude variations of the intensive high-frequency signal.Key words: modulation of sound by sound, amplitude modulation, phase modulation, grainy medium.