US3794816A
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Digital filters with impulse response modified by data circulations occurring between successive data inputs
Assignee: International Business Machines Corp
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Filing: 1972-03-17
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Granted: 1974-02-26
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Expires: 1992-03-17
Abstract
Abstract WHERE R BEING THE NUMBER OF INPUT DIGITS THAT CAN BE SIMULTANEOUSLY WEIGHTED, H(IT) being the filter impulse response or coefficient at frequency F. Usually, such filters exhibit a comb type impulse response spectrum of the form In a digital filter to which is applied a succession of binary coded input signals X(NT), X(NT-T), -X(NT-iT) -X(NT (N-1)T) at a frequency F 1/T, the filter output in the time domain at time NT being related to the input by the approximation
Inventors
- 👤 D Esteban
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:50
CPC Classifications
H; H03; H03H; H03H17/00; H03H17/02; H03H17/06; H03H17/0607
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
49 words
In a digital filter comprising: an r stage shift register; means for applying a succession of binary coded signals X(NT), X(NT-T)-X(NT-iT)-to the register at the rate F 1/T; means responsive to the shift register contents for forming an output signal in the time domain according to the convolution relation
Claim 2
Dependent Claim
49 words
In a digital filter comprising: an r stage shift register; means for applying a succession of binary coded signals X(NT), X(NT-T)-X(NT-iT)-to the register at the rate F 1/T; means responsive to the shift register contents for forming an output signal in the time domain according to the convolution relation
Claim 3
Dependent Claim
24 words
In a digital filter according to claim 1 wherein the number of zero amplitudes of the comb type spectrum vary as the ratio (m/n).
Claim 4
Dependent Claim
123 words
A digital filter comprising: an r stage shift register; means for applying a succession of binary coded signals to the register at the rate (1/T); an accumulator for algebraically combining binary coded signals; memory means for storing coefficient weighted signals in 2r addressable memory locations; means for extracting from the memory means the contents stored at the location whose address is defined by the r register stages and for applying said extracted contents to the accumulator, said extracting means including means operative during the interval T occurring between successive application of signals to the register for repeatedly extracting from memory and applying the contents thereof to the accumulator at a rate of (n/T) of which m out of n results being retained, m<n<(1/T).
Claim 5
Dependent Claim
123 words
A digital filter comprising: an r stage shift register; means for applying a succession of binary coded signals to the register at the rate (1/T); an accumulator for algebraically combining binary coded signals; memory means for storing coefficient weighted signals in 2r addressable memory locations; means for extracting from the memory means the contents stored at the location whose address is defined by the r register stages and for applying said extracted contents to the accumulator, said extracting means including means operative during the interval T occurring between successive application of signals to the register for repeatedly extracting from memory and applying the contents thereof to the accumulator at a rate of (n/T) of which m out of n results being retained, m<n<(1/T).
Claim 6
Dependent Claim
36 words
A digital filter according to claim 3, wherein the filter exhibits a comb type impulse response spectrum in the frequency domain of the form Y (jw) (sin(mwT/2N))/(sin(wT/2n)) where the number of spectrum zeros varies as m/n.
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) | 1977-02-25 | 1977-08-27 | 1978-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-25 | 1981-08-27 | 1982-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-25 | 1985-08-27 | 1986-02-26 | $7700.00 | Window Closed / Lapsed |