Noise activated automatic volume control

Abstract

Communications operators who must use receivers in a noisy audio environment without earphones are plagued by the effect of a varying background noise level. Often the operators are simultaneously performing other tasks thus can only monitor voice circuits. As the noise level varies the operator must repeatedly adjust the volume control for a comfortable listening level. An analysis of the physical situation is presented. An automatic feedback control system that measures the predominate range of frequencies of the background noise and automatically adjust the volume control of a power amplifier for a satisfactory listening level is developed. This system relieves the operator of the task of manual volume control and reduces the effect of noise masking.