Coded data generation or conversion – Converter calibration or testing
Patent
1992-09-29
1994-04-19
Young, Brian K.
Coded data generation or conversion
Converter calibration or testing
341143, H03M 110
Patent
active
053050045
ABSTRACT:
A second order sigma delta modulator (10) includes a digital to analog converter (26) that provides feedback for system modulation. The digital to analog converter (26) employs a dynamic element matching circuit (72) which randomly selects among main capacitors (C.sub.j) to reduce the effect of capacitor value mismatching. The digital to analog converter (26) also employs a self calibration circuit (80) to trim the values of the main capacitors (C.sub.j) to obtain better capacitor matching. During self calibration, a clock signal (f.sub.rand) driving a pseudo random number generator (74) of the dynamic element matching circuit (72) is reduced to assist in minimizing variance in a digital output signal for accurate calibration of the main capacitors (C.sub.j). Upon completion of calibration, the clock signal (f.sub.rand) is returned to a frequency coinciding with the modulator clock rate.
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patent: 5006854 (1991-04-01), White et al.
patent: 5144308 (1992-01-01), Norsworthy
patent: 5191331 (1993-03-01), Karema et al.
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"Second-Order Sigma-Delta Modulation for Digital-Audio Signal Acquisition", Brian P. Brandt, Drew E. Wingard, and Bruce A. Wooley, IEEE Journal of Solid-State Circuits, vol. 26, No. 4, Apr. 1991, pp. 618-627.
"Error Correction Techniques for High-Performance Differential A/D Converters", Khen-Sang Tan, Sami Kiriaki, Michiel DeWit, John W. Fattaruso, Ching-Yuh Tsay, W. Edward Matthews, and Richard K. Hester, IEEE Journal of Solid-State Circuits, vol. 25, No. 6, Dec. 1990, pp. 1318-1327.
"A 16-Bit 4'th Order Noise-Shaping D/A Converter", L. Richard Carley and John Kenney, IEEE, 1988, pp. 21.7.1-21.7.4.
Donaldson Richard L.
Garner Jacqueline J.
Hiller William E.
Texas Instruments Incorporated
Young Brian K.
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