Loudspeaker automatic volume control - adjusts to background noise level and has delayed volume reduction to avoid volume pulsing

摘要

The automatic volume control for loudspeaker automatically adjusts to the level of background noise. A signal (UP) representing the product of an input voltage (US) and a second voltage (UF) is formed and added to the original input voltage to form a fourth signal (UL). The product signal (UP) rises rapidly as the level of interference increases and falls slowly as the interference level drops. The fourth signal is used to drive the loudspeaker. The advantage of delaying the drop in volume to its 'normal' level lies in preventing unpleasant volumen fluctuations in response to intermittent interference repeated at short intervals.