Abstract: A digital signal converter (CNV) converts a digital input signal (PCM) into a pulse width modulated signal (PWM), which is a binary signal that comprises pulses of varying width. The digital signal converter can operate in a signal mode and a transition mode. In the transition mode, the digital converter provides the pulse width modulated signal (PWM) by applying an anti-transient noise shaping function (NSH2) to a direct current modification signal (SC). In the signal mode, the digital signal converter provides the pulse width modulated signal by applying a signal noise shaping function (NSH1) to the digital input signal.

Abstract: A pulse-width modulation (PWM) amplifier comprises a feedback loop for reshaping the pulses of the PWM input signal to correct timing and amplitude errors in the class D output stage of the amplifier by means of an error correction signal. In such an amplifier the feedback loop gives a substantial amount of base-band noise when the pulse-period of the PWM input signal is not constant, which is especially the case when the PWM signal originates from a noise shaper. The invention reduces this noise by modifying the reshaping gain of the amplifier with a pulse-period proportional signal.

Abstract: A pulse-width modulation (PWM) amplifier comprises a feedback loop for reshaping the pulses of the PWM input signal to correct timing and amplitude errors in the class D output stage of the amplifier by means of an error correction signal. In such an amplifier the feedback loop gives a substantial amount of base-band noise when the pulse-period of the PWM input signal is not constant, which is especially the case when the PWM signal originates from a noise shaper. The invention reduces this noise by modifying the reshaping gain of the amplifier with a pulse-period proportional signal.