US3703632A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Recursion filter
Assignee: BP America Production Co
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Filing: 1972-02-18
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Granted: 1972-11-21
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Expires: 1992-02-18
Abstract
Abstract This invention concerns apparatus for filtering signals. Means are provided for emphasizing only some of the frequency components of signals with respect to others. The invention has particular application where the signal to be applied to the filter consists of a set of data obtained by sampling the amplitude of the signal at substantially equal time intervals, i.e., digitized data. In this context, I provide apparatus for extremely high speed digital filtering. Automatically the terms in the equation ARE CARRIED OUT BY RECURSION, OR A COMBINATION OF FEED FORWARD AND FEED BACK TERMS. The quantities ai and bj are stored in a register. Values bj are automatically called out as appropriate, multiplied by the previous values of the coefficient yn, i.e., yn j (which is the recursive part) and summed, while the coefficients ai are called out and multiplied by the appropriate value of x, then the total summation is made. The apparatus involves both storage means, means for reading out the various values involved, multiplying them together, accumulating them and using a recursive path by which input data can be re-stored in a particular register, as desired.
Inventors
- 👤 John L Shanks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:47
CPC Classifications
H; H03; H03H; H03H17/00; H03H17/02; H03H17/04
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
250 words
Apparatus for recursively filtering a set of data xo, x1, x2, . . . xp in accordance with the recursive filtering formula in which ai and bj are filter coefficients, and N and M are positive integers, comprising 1. a first file storage containing a plurality of memory cells, 2. means for automatically storing said set of data in order in the memory cells of said first file storage, 3. a second file storage containing a plurality of memory cells, 4. means for automatically storing a set of filter coefficients in order in the memory cells of said second file storage, 5. two separate read controls connected respectively to said first and second file storages for producing two separate signals in two separate channels, one from each of said file storages, directly responsive to the data in the memory cells of said file storages to which connection has been made, 6. a multiplier connected to said channels for producing the product of said two separate signals, 7. an accumulator connected to the output of said multiplier for summing a plurality of outputs of said multiplier, 8. means for automatically feeding back the output of said accumulator to store said output in said means 2) and simultaneously feeding said output of said apparatus, and 9. an automatic controller connected to and operating cyclically on said means 2) for selecting successive memory cells in said first file storage for storage of the output of said accumulator in accordance with a predetermined pattern.
Claim 2
Dependent Claim
250 words
Apparatus for recursively filtering a set of data xo, x1, x2, . . . xp in accordance with the recursive filtering formula in which ai and bj are filter coefficients, and N and M are positive integers, comprising 1. a first file storage containing a plurality of memory cells, 2. means for automatically storing said set of data in order in the memory cells of said first file storage, 3. a second file storage containing a plurality of memory cells, 4. means for automatically storing a set of filter coefficients in order in the memory cells of said second file storage, 5. two separate read controls connected respectively to said first and second file storages for producing two separate signals in two separate channels, one from each of said file storages, directly responsive to the data in the memory cells of said file storages to which connection has been made, 6. a multiplier connected to said channels for producing the product of said two separate signals, 7. an accumulator connected to the output of said multiplier for summing a plurality of outputs of said multiplier, 8. means for automatically feeding back the output of said accumulator to store said output in said means 2) and simultaneously feeding said output of said apparatus, and 9. an automatic controller connected to and operating cyclically on said means 2) for selecting successive memory cells in said first file storage for storage of the output of said accumulator in accordance with a predetermined pattern.
Claim 3
Dependent Claim
38 words
Apparatus for recursively filtering a set of data xo, x1, x2, . . . xp in accordance with the recursive filtering formula in which ai and bj are filter coefficients, and N and M are positive integers, comprising
Claim 4
Dependent Claim
38 words
Apparatus for recursively filtering a set of data xo, x1, x2, . . . xp in accordance with the recursive filtering formula in which ai and bj are filter coefficients, and N and M are positive integers, comprising
Claim 5
Dependent Claim
10 words
a first file storage containing a plurality of memory cells,
Claim 6
Dependent Claim
10 words
a first file storage containing a plurality of memory cells,
Claim 7
Dependent Claim
19 words
means for automatically storing said set of data in order in the memory cells of said first file storage,
Claim 8
Dependent Claim
19 words
means for automatically storing said set of data in order in the memory cells of said first file storage,
Claim 9
Dependent Claim
45 words
Apparatus in accordance with claim 1 in which said means 2) stores said set of data in order of the subscripts into successive memory cells in said first file storage starting at the cell which is M+N units after the initial cell in said storage.
Claim 10
Dependent Claim
53 words
Apparatus in accordance with claim 2 in which said means 4) for storing said filter coefficients ai and bj sTores said coefficients serially in the memory cells of said second file storage in the arrangement -bM, -bM 1, -bM 2, . . . -b1, aN, aN 1, aN 2, . . . ao.
Claim 11
Dependent Claim
10 words
a second file storage containing a plurality of memory cells,
Claim 12
Dependent Claim
10 words
a second file storage containing a plurality of memory cells,
Claim 13
Dependent Claim
20 words
means for automatically storing a set of filter coefficients in order in the memory cells of said second file storage,
Claim 14
Dependent Claim
20 words
means for automatically storing a set of filter coefficients in order in the memory cells of said second file storage,
Claim 15
Dependent Claim
85 words
Apparatus in accordance with claim 3 including in said automatic controller means connected to said read controls 5) for producing separately but simultaneously signals from the initial cells of said first file storage and said second file storage, then separately but simultaneously from the second cells of said first file storage and said second file storage, and so on, until the number of terms so produced from said second file storage equals the total number M+N+1 of filter coefficients stored in said second file storage.
Claim 16
Dependent Claim
70 words
Apparatus in accordance with claim 4 in which said means for producing signals separately but simultaneously is repeatedly initiated, and in which said controller means includes means for incrementing by one the number of the first memory cell in said first file storage relative to that in said second file storage after the production of each M+N+1 such signals and the feeding back of said accumulator output by means 8).
Claim 17
Dependent Claim
48 words
two separate read controls connected respectively to said first and second file storages for producing two separate signals in two separate channels, one from each of said file storages, directly responsive to the data in the memory cells of said file storages to which connection has been made,
Claim 18
Dependent Claim
48 words
two separate read controls connected respectively to said first and second file storages for producing two separate signals in two separate channels, one from each of said file storages, directly responsive to the data in the memory cells of said file storages to which connection has been made,
Claim 19
Dependent Claim
18 words
an accumulator connected to the output of said multiplier for summing a plurality of outputs of said multiplier,
Claim 20
Dependent Claim
18 words
an accumulator connected to the output of said multiplier for summing a plurality of outputs of said multiplier,
Claim 21
Dependent Claim
27 words
means for automatically feeding back the output of said accumulator to store said output in said means 2) and simultaneously feeding said output of said apparatus, and
Claim 22
Dependent Claim
27 words
means for automatically feeding back the output of said accumulator to store said output in said means 2) and simultaneously feeding said output of said apparatus, and
Claim 23
Dependent Claim
36 words
an automatic controller connected to and operating cyclically on said means 2) for selecting successive memory cells in said first file storage for storage of the output of said accumulator in accordance with a predetermined pattern.
Claim 24
Dependent Claim
36 words
an automatic controller connected to and operating cyclically on said means 2) for selecting successive memory cells in said first file storage for storage of the output of said accumulator in accordance with a predetermined pattern.
References Cited (Backward Citations)
US3639739A
Cited
US3651316A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-11-21 | 1976-05-22 | 1976-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-21 | 1980-05-22 | 1980-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-21 | 1984-05-22 | 1984-11-21 | $7700.00 | Window Closed / Lapsed |