Title :
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
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;
Conference_Titel :
Analogue to Digital and Digital to Analogue Conversion, 1991., International Conference on
Conference_Location :
Swansea
Print_ISBN :
0-85296-524-9
