Patent ID: 8774427

Claim:
An audio processing system, comprising: an audio processor, receiving a data signal, and processing the data signal to generate a processed signal, wherein the audio processor comprises: a first gain control circuit and a second gain control circuit for generating a gain signal; and an operational amplifier coupled to the first and second gain control circuits to amplify the data signal by the gain signal to generate the processed signal; and an audio amplifier, coupling to the audio processor, and amplifying the processed signal to generate an amplified signal, wherein: the operational amplifier comprises a differential operational amplifier having a first input terminal, a second input terminal, a first output terminal, and a second output terminal; the first gain control circuit is coupled to the first input terminal of the differential operational amplifier and controlled by the data signal, a signal at the first output terminal of the differential operational amplifier and a volume control signal; and the second gain control circuit is coupled to the second input terminal of the differential operational amplifier and controlled by a reference voltage, a signal at the second output terminal of the differential operational amplifier and the volume control signal.