Patent ID: 8494180
Filing Date: 2013-07-23
Classification: H03F

Abstract:
1. A method for use with a digital pulse width modulation (PWM) amplifier that includes a noise shaper adapted to perform quantization of an audio data signal and shape noise resulting from quantization of the audio data signal using noise shaper filter coefficients, the method comprising: monitoring an audio data signal for an idle channel condition; using predetermined values for the noise shaper filter coefficients to shape the noise resulting from quantization of the audio data signal while the idle channel condition is not being detected; reducing the values of the noise shaper filter coefficients so that the values move toward zeros, and using the reduced values of the noise shaper filter coefficients to attenuate noise resulting from quantization of the audio data signal, while the idle channel condition is being detected; if all the values of the noise shaper filter coefficients are reduced to zeros while the idle channel condition is being detected, maintaining the values of the noise shaper filter coefficients at zeros until the idle channel condition is no longer detected; and returning the noise shaper filter coefficients to the predetermined values when the idle channel condition is no longer detected.