Variable sample rate DAC

Details Variable sample rate DAC Variable sample rate DAC

1995-06-06

1997-02-04

Williams, Howard L.

Coded data generation or conversion

Analog to or from digital conversion

Digital to analog conversion

341 61, 341143, H03M 166

Patent

active

056003200

ABSTRACT:
A method and apparatus for digital-to-analog conversion using sigma-delta modulation of the temporal spacing between digital samples are provided. The method and apparatus include sigma-delta modulation of the time-base such that errors produced by non-uniform sampling are frequency-shaped to a high frequency region where they are reduced by conventional filtering techniques. In one embodiment, an oversampling modulator receives digital input samples and, responsive to a noise-shaped clock signal, modulates the digital input samples to produce modulated samples at an oversampling rate. The oversampling rate preferably is equal to an oversampling ratio times a preselected input sample rate. A DAC, coupled to the modulator, converts the modulated samples to an analog signal. A modulator sample rate control circuit, coupled to the modulator, receives a frequency select signal representing the preselected input sample rate, and produces the noise-shaped clock signal for controlling operation of the modulator at the oversampling rate. The control circuit preferably includes a first sigma-delta modulator that sigma-delta modulates the frequency select signal. The oversampling modulator preferably includes a second sigma-delta modulator.

REFERENCES:
patent: 4179670 (1979-12-01), Kingsbury
patent: 4281318 (1981-07-01), Candy et al.
patent: 4797845 (1989-01-01), Stikvoort
patent: 4953117 (1990-08-01), Lagadec
patent: 4954824 (1990-09-01), Yamada et al.
patent: 4987373 (1991-01-01), Soo
patent: 4990911 (1991-02-01), Fujita et al.
patent: 5075679 (1991-12-01), Gazsi
patent: 5111417 (1992-05-01), Belloc et al.
patent: 5119093 (1992-06-01), Vogt et al.
patent: 5121065 (1992-06-01), Wagner
patent: 5157395 (1992-10-01), Del Signore et al.
patent: 5204827 (1993-04-01), Fujita et al.
patent: 5227787 (1993-07-01), Kurashina
patent: 5313205 (1994-05-01), Wilson
patent: 5353026 (1994-10-01), Wilson
J. Janssen, et al. An Audio Engineering Society Preprint Feb. 26--Mar. 1, 1994.
Richard J. Higgins, Digital Signal Processing in VLSI, Prentice Hall, Englewood Cliffs, NJ 07632.
Doulas F. Elliott, et al, Fast Transforms, Algorithms, Analyses, Applications, 1982, Academic Press.
Paul J. Hurst, et al. A Programmable Clock Generator Using Noise Shaping and Its Application in a Switched-Capacitor Filter, Solid State Circuits Research Laboratory, Dept. of Electrical and Computer Engineering, University of California, Davis.

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