Applied Physics and Mathematics Annotation << Back Analysis of the envelope detector device attenuation of acoustic feedback А.L. Galiev R.G. Galieva А.F. Shishkina The article is an analysis of the qualitative characteristics of the envelope detector is used in devices attenuation of acoustic feedback companding envelope of the speech signal. The detector is formed by an operational amplifier circuit for half-wave rectifier, which allows to realize a linear detector response over a wide range of signal amplitudes. To obtain analytical expressions, quite accurately describe the operation of the detector, the detector characteristics used approximation, which satisfies most types of semiconductor diodes. Thus the speech signal is considered as a unit of the amplitude-modulated signal. Analysis of the mathematical model and experimental studies of the detector shown that its inclusion in the circuit shifts the phase of the envelope , the range which does not exceed one or two periods of the frequency of the speech signal . Small displacement does not reduce the quality and intelligibility, but manifested in the form of non-linear distortion of the synthesized signal. Keywords: envelope detector, acoustic feedback, phase shift, total harmonic distortion (THD), operational amplifier. Contacts: E-mail: galievanvar@mail.ru Pp. 20-23.