Patent ID: 6049618
Filing Date: 2000-04-11
Classification: H03G,H04R

Abstract:
A hearing aid circuit adapted for connection to a microphone and a receiver, comprising:a variable gain amplifier having an input, an output and a gain control input, the gain of the variable gain amplifier being determined by an electrical signal present at the gain control input, and the variable gain amplifier being so connected that electrical signals at its input are determined by electrical signals from the microphone;a power amplifier having an input and an output, the output being adapted for connection to the receiver, and the power amplifier being so connected that signals at its input are determined by signals at the output of the variable gain amplifier;an input network responding to electrical signals at the input of the variable gain amplifier and producing an input AGC signal;an output network responding to electrical signals at the input of the power amplifier and producing an output AGC signal;a summing circuit connected to the input and output networks and producing a summed AGC signal; andan attack/release circuit connected between the summing circuit and the gain control input, the attack/release circuit responding to the summed AGC signal and producing an electrical signal at the gain control input.