A PWM DAC for digital audio power conversion: from theory to performance

Author

Hiorns, R.E. ; Bowman, R.G. ; Sandler, M.B.

Author_Institution

King´´s Coll. London, UK

fYear

1991

fDate

17-19 Sep 1991

Firstpage

142

Lastpage

147

Abstract

Digital pulse width modulation (PWM) is combined with simple noise shaping to convert 8 times Nyquist sampled digital audio signals directly to analogue audio. A digital interpolating filter is used to provide such over-sampled test signals from a compact disc (CD). A low noise crystal based oscillator is used to synchronise the required digital elements via fast asynchronous counters based on 1.3 μ CMOS. Output is suitable for power-efficient control of MOSFET switching devices and can be used directly, giving >100 dB dynamic range and >120 dB peak signal to noise floor ratio. Comparison between a pulse amplitude modulation (PAM) digital to analogue converter (DAC) and the PWM converter is shown using spectral plots. The PWM unit is shown to follow theoretical analysis very closely

Keywords

audio equipment; digital-analogue conversion; pulse width modulation; CMOS; DAC; MOSFET switching devices; Nyquist sampled digital audio signals; analogue audio; asynchronous counters; compact disc; digital PWM; digital audio power conversion; digital interpolating filter; dynamic range; low noise crystal based oscillator; noise shaping; over-sampled test signals; power-efficient control; signal to noise floor ratio; spectral plots;

fLanguage

English

Publisher

iet

Conference_Titel

Analogue to Digital and Digital to Analogue Conversion, 1991., International Conference on

Conference_Location

Swansea

Print_ISBN

0-85296-524-9

Type

conf

Filename

151989