Digital-PWM audio power amplifiers with noise and ripple shaping

This paper presents a digital pulse width modulation (PWM) technique featuring noise and ripple shaping for audio power amplification. The sampled power-source amplitude signal is used to shape the interpolated input digital signal, which is fed to a noise shaper to produce a lower bit digital signal to represent the original signal. The output power signal is not affected by the requantization error or the power-source ripple. Therefore, DC power regulators can be eliminated without sacrificing the signal-to-noise ratio. Spectral analysis is provided for double edge uniform sampling modulation.<
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