Title:
NOISE-SHAPED DIGITAL FREQUENCY SYNTHESIS
Document Type and Number:
WIPO Patent Application WO2002017050
Kind Code:
A3
Abstract:
A clock generator for automatic test equipment generates clock signals from a reference clock. To generate a desired clock signal, a clock generator produces a time-quantized signal having a period equal to an integer number of reference clock periods and equal to the desired clock period, plus or minus a quantization error. For each cycle of the desired clock signal, a noise-shaping requantizer processes the quantization error to generate noise-shaping signals. The noise-shaping signals then establish delay values of a variable pipeline delay. The variable pipeline delay adjusts each period of the time-quantized signal by an integer number of reference clock cycles, based upon the noise-shaped signals. The effect of noise shaping the quantization error and selectively delaying the time-quantized signal is to shift jitter in the time-quantized signal from relatively low frequencies to relatively high frequencies, which can be filtered with a phase-locked loop.
Inventors:
SHEEN TIMOTHY W
Application Number:
PCT/US2001/024085
Publication Date:
July 18, 2002
Filing Date:
August 01, 2001
Export Citation:
Assignee:
TERADYNE INC (US)
International Classes:
H03K5/00; G06F1/025; H03B28/00; H03L1/00; H03L7/081; H03L7/16; H03M3/02; (IPC1-7): G06F1/025; G06F7/68
Foreign References:
| US5627500A | 1997-05-06 | |||
| US5808493A | 1998-09-15 |
Other References:
VEILLETTE B R ET AL: "STIMULUS GENERATION FOR BUILT-IN SELF-TEST OF CHARGE-PUMP PHASE- LOCKED LOOPS", PROCEEDINGS OF THE INTERNATIONAL TEST CONFERENCE 1998. ITC '98. WASHINGTON, DC, OCT. 19 - 20, 1998, INTERNATIONAL TEST CONFERENCE, NEW YORK, NY: IEEE, US, vol. CONF. 29, 19 October 1998 (1998-10-19), pages 698 - 707, XP000822411, ISBN: 0-7803-5093-6
GHOSH S: "NONINTEGER DIVISION SYNTHESIZES MULTIPLE CLOCK FREQUENCIES", EDN ELECTRICAL DESIGN NEWS, CAHNERS PUBLISHING CO. NEWTON, MASSACHUSETTS, US, vol. 36, no. 4, 18 February 1991 (1991-02-18), pages 169 - 172,174,17, XP000222688, ISSN: 0012-7515
GHOSH S: "NONINTEGER DIVISION SYNTHESIZES MULTIPLE CLOCK FREQUENCIES", EDN ELECTRICAL DESIGN NEWS, CAHNERS PUBLISHING CO. NEWTON, MASSACHUSETTS, US, vol. 36, no. 4, 18 February 1991 (1991-02-18), pages 169 - 172,174,17, XP000222688, ISSN: 0012-7515
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