to a standard am radio receiver there is connected an impulse - noise suppression system comprising a preliminary blanking gate adapted for connecting to and for interrupting the am - modulated signal path at the input of the if section , and an audio blanking gate adapted for interrupting the audio circuit . both blanking circuits detect impulse noise at the rf amplifier and with appropriate delays blank both points . audio blanking masks the audio disturbance caused by the blanking in the am - modulated - signal path . audio blanking time is preferably from 2 to 3 times the duration of the blanking of the am - modulated - signal path and is thus kept very short causing a minimum interruption of the wanted audio signal . associated with the audio - signal - path blanking circuit is a sample and hold circuit for smoothing the blanked audio signal and virtually eliminating an audio disturbance or noise that is otherwise generated by the audio blanking circuit itself .