Patent ID: 6493450
Filing Date: 2002-12-10
Classification: H03G

Abstract:
An automatic squelch for an intercom system used in a small aircraft or other high noise environment, said automatic squelch comprising:an analog to digital converter coupled to receive an analog microphone input signal and configured to convert said analog microphone input signal into a digital input signal; a microcontroller coupled to said analog to digital converter and configured to execute a plurality of instructions; a memory configured to store said plurality of instructions; wherein execution of said plurality of instructions by said microcontroller includes: maintaining a peak value indicative of peaks in said digital input signal; maintaining a background noise digital value indicative of background noise, wherein said background noise digital value is adjusted in response to a result of comparing said peak value with said background noise digital value; determining a threshold value which depends upon said background noise digital value; comparing said threshold value to a value indicative of said digital input signal; and asserting a one shot signal for activating a microphone input path in response to a result of comparing said threshold value to said value indicative of said digital input signal.