Generation of Variable Frequency Digital PWM

Midya P. Generation of Variable Frequency Digital PWM. In: AES Convention 123. Audio Engineering Society; 2007. Paper 7227. Available from: https://aes.org/publications/elibrary-page/?id=14285

@inproceedings{Midya2007_14285,
  author = {Midya, Pallab},
  title = {{Generation of Variable Frequency Digital PWM}},
  booktitle = {AES Convention 123},
  note = {Paper 7227},
  year = {2007},
  month = oct,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=14285}
}

TY  - CPAPER
TI  - Generation of Variable Frequency Digital PWM
AU  - Midya, Pallab
T2  - AES Convention 123
M1  - Paper 7227
PY  - 2007
DA  - 2007/10/06
UR  - https://aes.org/publications/elibrary-page/?id=14285
PB  - Audio Engineering Society
LA  - en
AB  - Digital audio amplifiers convert digital PCM to digital PWM to be amplified by a power stage. This paper introduces a method to generate a quantized duty ratio digital PWM with a switching frequency that varies over a 20% range to mitigate EMI issues. The method is able to compensate for the variation in switching frequency such that the SNR in the audio band is comparable to fixed frequency PWM. To obtain good rejection of the noise introduced by the variation of the PWM frequency higher order noise shapers are used. This paper describes in detail the algorithm for a fourth order noise shaper. Using this method dynamic range in excess of 120 dB un-weighted over a 20 kHz bandwidth is achieved.
ER  -