Patent US5987484A successfully refreshed from Google Patents.
US5987484A
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Digital filtering system
Assignee: Analog Devices Inc
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Filing: 1998-04-07
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Granted: 1999-11-16
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Expires: 2018-04-07
Abstract
Abstract A digital filtering system is fed by input signal and produces an output signal from either a relatively low bandwidth filter or a relatively wide bandwidth filter selectively in accordance with the time rate of change in the input signal. The output signal is produced by the relatively low bandwidth filter when the input signal is slowly varying and the output signal is produced by the relatively wide bandwidth filter when the input signal changes rapidly, after which the output is produced from the relatively low bandwidth filter when the input signal reverts to its more slowly varying characteristics.
Inventors
- 👤 Adrian Sherry
- 👤 Damien McCartney
- 👤 Michael Byrne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:10
CPC Classifications
G; G06; G06F; G06F17/00; G06F17/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
85 words
A digital filtering system for filtering samples of a input signal fed thereto, comprising; a moving average filter having a variable averaging factor N; a control section for varying the variable averaging factor N in accordance with a determined difference in level between a pair of the samples relative to a threshold level, the averaging factor N being N 0 when the determined difference is greater than the threshold level and is then successively increased once the determined difference is less than the threshold level.
Claim 2
Dependent Claim
85 words
A digital filtering system for filtering samples of a input signal fed thereto, comprising; a moving average filter having a variable averaging factor N; a control section for varying the variable averaging factor N in accordance with a determined difference in level between a pair of the samples relative to a threshold level, the averaging factor N being N 0 when the determined difference is greater than the threshold level and is then successively increased once the determined difference is less than the threshold level.
Claim 3
Dependent Claim
11 words
The system recited in claim 1 wherein N 0 is 2.
Claim 4
Dependent Claim
39 words
The system recited in claim 2 wherein N is successively increased by factors of 2 to 2 i once (2 i -1) samples have been fed to the digital filter with the determined difference less than the threshold level.
Claim 5
Dependent Claim
10 words
The system recited in claim 1 wherein No is 1.
Claim 6
Dependent Claim
39 words
The system recited in claim 4 wherein N is successively increased by factors of 2 to 2 i once (2 i -1) samples have been fed to the digital filter with the determined difference less than the threshold level.
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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) | 2002-11-15 | 2003-05-17 | 2003-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-11-15 | 2007-05-17 | 2007-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-11-15 | 2011-05-17 | 2011-11-16 | $7700.00 | Window Closed / Lapsed |