US5760722A
Expired / Lapsed
US
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Distributed quantization noise transmission zeros in cascaded sigma-delta modulators
Assignee: United States Department of the Navy
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Filing: 1995-01-31
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Granted: 1998-06-02
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Expires: 2015-01-31
Abstract
Abstract A series of sigma-delta modulators are connected in a cascaded architecture. Each sigma-delta modulator has a noise transfer function that defines a unique set of quantization noise transmission zeros. A circuit is coupled to the cascaded architecture and has a signal transfer function that is an approximation of the noise transfer function of a first sigma-delta modulator in the series of sigma-delta modulators.
Inventors
- 👤 Frederick J. Harris
- 👤 Robert W. Caulfield
- 👤 William H. McKnight
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:11
CPC Classifications
H; H03; H03M; H03M3/00; H03M3/30; H03M3/322; H03M3/368; H03M3/39; H03M3/412; H03M3/414; H03M3/418
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
75 words
An apparatus, comprising: a plurality of sigma-delta modulators connected in a cascaded architecture, each of said plurality of sigma-delta modulators having a noise transfer function that defines a unique set of quantization noise transmission zeros; and circuit means coupled to said cascaded architecture of said plurality of sigma-delta modulators, said circuit means having a signal transfer function that is an approximation of a noise transfer function of a first of said plurality of sigma-delta modulators.
Claim 2
Independent Claim
75 words
An apparatus, comprising: a plurality of sigma-delta modulators connected in a cascaded architecture, each of said plurality of sigma-delta modulators having a noise transfer function that defines a unique set of quantization noise transmission zeros; and circuit means coupled to said cascaded architecture of said plurality of sigma-delta modulators, said circuit means having a signal transfer function that is an approximation of a noise transfer function of a first of said plurality of sigma-delta modulators.
Claim 3
Dependent Claim
17 words
An apparatus as in claim 1 wherein each of said plurality of sigma-delta modulators includes m integrators.
Claim 4
Dependent Claim
8 words
An apparatus as in claim 2 wherein m≧2.
Claim 5
Dependent Claim
20 words
An apparatus as in claim 1 wherein each of said plurality of sigma-delta modulators is tuned to a selected passband.
Claim 6
Independent Claim
116 words
An apparatus, comprising: a plurality of sigma-delta modulators connected in a cascaded architecture, each of said plurality of sigma-delta modulators producing a quantized output and having a noise transfer function that defines a unique set of quantization noise transmission zeros, said cascaded architecture including a first sigma-delta modulator receiving an input to be conditioned and a last sigma-delta modulator; circuit means coupled to said quantized output of said last sigma-delta modulator, said circuit means having an output defined by a signal transfer function that is an approximation of a noise transfer function of said first sigma-delta modulator; and means for differencing said quantized output of said first sigma-delta modulator with said output of said circuit means.
Claim 7
Independent Claim
116 words
An apparatus, comprising: a plurality of sigma-delta modulators connected in a cascaded architecture, each of said plurality of sigma-delta modulators producing a quantized output and having a noise transfer function that defines a unique set of quantization noise transmission zeros, said cascaded architecture including a first sigma-delta modulator receiving an input to be conditioned and a last sigma-delta modulator; circuit means coupled to said quantized output of said last sigma-delta modulator, said circuit means having an output defined by a signal transfer function that is an approximation of a noise transfer function of said first sigma-delta modulator; and means for differencing said quantized output of said first sigma-delta modulator with said output of said circuit means.
Claim 8
Dependent Claim
17 words
An apparatus as in claim 5 wherein each of said plurality of sigma-delta modulators includes m integrators.
Claim 9
Dependent Claim
8 words
An apparatus as in claim 6 wherein m≧2.
Claim 10
Dependent Claim
20 words
An apparatus as in claim 5 wherein each of said plurality of sigma-delta modulators is tuned to a selected passband.
Claim 11
Dependent Claim
17 words
An apparatus as in claim 5 further comprising a decimation filter coupled to said means for differencing.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-06-01 | 2001-12-01 | 2002-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-01 | 2005-12-01 | 2006-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-01 | 2009-12-01 | 2010-06-02 | $7700.00 | Window Closed / Lapsed |