Patent ID: 7706525

Claim:
A side-tone circuit, comprising: a single microphone configured to generate a reverse link audio signal having environmental noise components and voice components in an audio band; an analog to digital converter (ADC) configured to convert the reverse link audio signal to a digital reverse link audio signal; a side-tone noise suppressor configured to: receive the digital reverse link audio signal, differentiate, based on the variability of signal levels over time, the audio band environmental noise components and the audio band voice components using only the digital reverse link audio signals; and suppress the audio band environmental noise components that do not vary significantly in signal level over time and pass the audio band voice components to generate a digital noise suppressed side-tone signal; a summing circuit configured to combine the digital noise suppressed side-tone signal with a forward link audio signal to generate a digital output signal; a digital to analog converter (DAC) configured to convert the digital output signal to an analog output signal; and a speaker configured to communicate the analog output signal to a user.