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US5043653A
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Noise filter for zero crossing detector
Assignee: Sundstrand Corp
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Filing: 1990-01-17
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Granted: 1991-08-27
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Expires: 2010-01-17
Abstract
Abstract A noise filter for the zero crossing detector of a digitized sine wave signal uses an adjustable noise integrator. The noise integrator incorporates a counter. The integration characteristic of the counter is adjustable by selecting a count rate or a count limit from a microprocessor memory.
Inventors
- 👤 Joseph E. Foster
- 👤 Abdul Rashid
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:25
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/153; H03K5/1536; H03K5/125; H03K5/1252
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
78 words
In an electrical generating system control responsive to system condition signals, including a digitized sine wave signal which is subject to noise, for monitoring generator speed and voltage, an improved means for detecting sine wave zero crossing of said digital sine wave signals, including: a filter for said digitized sine wave signal, said filter including a noise integrator which integrates the noise accompanying the sine wave, the output of the filter indicating zero crossing of the sine wave.
Claim 2
Dependent Claim
78 words
In an electrical generating system control responsive to system condition signals, including a digitized sine wave signal which is subject to noise, for monitoring generator speed and voltage, an improved means for detecting sine wave zero crossing of said digital sine wave signals, including: a filter for said digitized sine wave signal, said filter including a noise integrator which integrates the noise accompanying the sine wave, the output of the filter indicating zero crossing of the sine wave.
Claim 3
Dependent Claim
14 words
The zero crossing detector of claim 1 in which said noise integrator is adjustable.
Claim 4
Dependent Claim
16 words
The zero crossing detector of claim 2 in which said noise integrator has an adjustable rate.
Claim 5
Dependent Claim
16 words
The zero crossing detector of claim 2 in which the noise integrator has an adjustable limit.
Claim 6
Dependent Claim
21 words
The zero crossing detector of claim 4 in which said noise integrator is bidirectional and has adjustable upper and lower limits.
Claim 7
Dependent Claim
31 words
The zero crossing detector of claim 2 in which said control includes a microprocessor and a memory, and said noise integrator has an adjustable characteristic selected from memory by said microprocessor.
Claim 8
Dependent Claim
17 words
The zero crossing detector of claim 1 in which said noise integrator is an up down counter.
Claim 9
Dependent Claim
16 words
The zero crossing detector of claim 7 in which said integrator has an adjustable counting rate.
Claim 10
Dependent Claim
21 words
The zero crossing detector of claim 7 in which said integrator is bidirectional and has adjustable upper and lower count limits.
References Cited (Backward Citations)
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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) | 1994-08-26 | 1995-02-25 | 1995-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-26 | 1999-02-25 | 1999-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-26 | 2003-02-25 | 2003-08-27 | $7700.00 | Window Closed / Lapsed |