Title :
Spread Spectrum PWM Signal Generator for Fully Digital Audio Amplifier
Author_Institution :
Nagoya Inst. of Technol., Nagoya
Abstract :
A generation scheme to make a low noise low distortion PWM signal spreading its spectrum for the fully digital audio amplifier is proposed. The carrier frequency of the PWM is fluctuated randomly to spread the spectrum of the carrier component. The noise-shaping filter in the delta-sigma modulator is implemented so that the filter works with a changing sampling period preserving the designed frequency characteristics. Such a filter is designed in continuous-time manner considering the distortion due to the PWM and is realized as a digital filter to compensate the effect of the sampling period fluctuation with feedback manner. A S/(N+D) ratio of over 120 dB is achieved for the generated PWM signal.
Keywords :
audio-frequency amplifiers; delta-sigma modulation; digital filters; pulse width modulation; signal generators; delta-sigma modulator; digital audio amplifier; digital filter; noise-shaping filter; sampling period fluctuation; spread spectrum PWM signal generator; Digital filters; Distortion; Frequency; Low-noise amplifiers; Noise generators; Noise shaping; Pulse width modulation; Sampling methods; Signal generators; Spread spectrum communication;
Conference_Titel :
Electronics, Circuits and Systems, 2006. ICECS '06. 13th IEEE International Conference on
Conference_Location :
Nice
Print_ISBN :
1-4244-0395-2
Electronic_ISBN :
1-4244-0395-2
DOI :
10.1109/ICECS.2006.379770
