US3872290A
Expired / Lapsed
US
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Finite impulse response digital filter with reduced storage
Assignee: Unisys Corp
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Filing: 1973-09-24
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Granted: 1975-03-18
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Expires: 1993-09-24
Abstract
Abstract An algorithm and instrumentation for a digital transversal filter utilizing a finite impulse response wherein storage is reduced by storing partial results of the convolution process for a number of output samples rather than storing input data.
Inventors
- 👤 Arthur W Crooke
- 👤 Paul H Schottler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:11
CPC Classifications
H; H03; H03H; H03H17/00; H03H17/02; H03H17/06
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
131 words
A digital filter comprising input means for receiving input digital signals representative of sequential samples of an analog waveform to be filtered, first storage means for storing digital samples of the impulse response of said filter, convolution means coupled to said input means and said first storage means for computing the discrete partial convolution of each current input sample with respect to said impulse response samples, second storage means included in said convolution means for simultaneously storing a plurality of the results of said partial convolution computations, and output means coupled to said second storage means for providing output digital signals representative of those of said plurality of partial convolution results completed by inclusion of a current input sample, thereby providing said output digital signals representative of said filtered analog waveform.
Claim 2
Dependent Claim
131 words
A digital filter comprising input means for receiving input digital signals representative of sequential samples of an analog waveform to be filtered, first storage means for storing digital samples of the impulse response of said filter, convolution means coupled to said input means and said first storage means for computing the discrete partial convolution of each current input sample with respect to said impulse response samples, second storage means included in said convolution means for simultaneously storing a plurality of the results of said partial convolution computations, and output means coupled to said second storage means for providing output digital signals representative of those of said plurality of partial convolution results completed by inclusion of a current input sample, thereby providing said output digital signals representative of said filtered analog waveform.
Claim 3
Dependent Claim
24 words
The digital filter of claim 1 further including means for resetting said completed partial results to zero after being provided to said output means.
Claim 4
Dependent Claim
76 words
The digital filter of claim 1 in which said convolution means further includes multiplier means coupled to said input means and said first storage means for multiplying each current input sample with said impulse response samples providing products thereof, respectively, and summation means coupled to said multiplier means and said second storage means for adding said products to said partial convolution results, respectively, thereby providing partial convolution results updated with respect to said current input sample.
Claim 5
Dependent Claim
59 words
The digital filter of claim 3 in which said second storage means comprises a second memory with an input coupled to the output of said summation means and with an output coupled to an input of said summation means, and control counter means coupled to said second memory for controlling the storage and updating of said partial convolution results.
Claim 6
Dependent Claim
50 words
The digital filter of claim 3 in which said first storage means comprises a first memory for storing said digital samples of said impulse response, and address counter means coupled to said first memory for controlling the sequential readout of every Jth impulse response sample, with J greater than unity.
Claim 7
Dependent Claim
54 words
The digital filter of claim 5 in which said address counter means comprises a coefficient address counter coupled to said first memory for controlling the sequential readout of every Jth impulse response sample, and an initial address counter coupled to said coefficient address counter for controlling the initial address for each said sequential readout.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-03-17 | 1978-09-16 | 1979-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-17 | 1982-09-16 | 1983-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-17 | 1986-09-16 | 1987-03-18 | $7700.00 | Window Closed / Lapsed |