US3696235A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital filter using weighting
Assignee: Lockheed Martin Corp
•
Filing: 1970-06-22
•
Granted: 1972-10-03
•
Expires: 1990-06-22
Abstract
Abstract Digital filter apparatus in which a set of weighting signal samples to be multiplied in the filter has values which are exactly powers of two such that the filter multiplier network may be comprised of simple signal routing circuits.
Inventors
- 👤 Donald W Tufts
- 👤 Ralph E Burt
- 👤 Victor I Davis Jr
- 👤 James F Queenan
- 👤 Richard A Maloon
- 👤 David W Waterman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 08:07
CPC Classifications
H; H03; H03H; H03H17/00; H03H17/02; H03H17/0248; H03H17/0264; G; G01; G01R; G01R23/00; H03H17/0223; H03H17/0225; H03H17/0227
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
160 words
Digital filter apparatus comprising signal generating means including first means for sequentially producing a set of information signal samples during an interval which is equal to the reciprocal T of the filter bandwidth, a clock source for producing clock signals, and means for deriving from said clock signals during said interval a set of weighting signal samples with values (1) which are exactly equal to Rn, where R is the radix with the values of n being selected to suppress the sidelobes of the filter frequency response and (2) which are constant for time durations which are Rm sub-multiples of the reciprocal T, where n and m are integers; radix point translating means responsive to the weighting signal samples to translate the radix points of the information signal samples a number of orders equal to the current values of n to thereby produce a resulting sequence of products; and summation means for algebraically summing said products over said interval T.
Claim 2
Dependent Claim
160 words
Digital filter apparatus comprising signal generating means including first means for sequentially producing a set of information signal samples during an interval which is equal to the reciprocal T of the filter bandwidth, a clock source for producing clock signals, and means for deriving from said clock signals during said interval a set of weighting signal samples with values (1) which are exactly equal to Rn, where R is the radix with the values of n being selected to suppress the sidelobes of the filter frequency response and (2) which are constant for time durations which are Rm sub-multiples of the reciprocal T, where n and m are integers; radix point translating means responsive to the weighting signal samples to translate the radix points of the information signal samples a number of orders equal to the current values of n to thereby produce a resulting sequence of products; and summation means for algebraically summing said products over said interval T.
Claim 3
Dependent Claim
72 words
The invention set forth in claim 1 wherein the radix R equals 2; and wherein n has first, second and third values, the first and third of which are maximum and minimum, respectively; the third value occurring during the first and last T/8 portions of said interval, the second value occurring during the second and next to last T/8 portions; and the first value occurring during the remaining portion of said interval.
Claim 4
Dependent Claim
55 words
The invention as set forth in claim 2 wherein said deriving means includes frequency divider means to provide first signals at N/4, N/8, and N/16 of the clock signal frequency where N is the number of samples in a set and further includes means for combining said first signals to produce said weighting signal samples.
References Cited (Backward Citations)
US3283131A
Cited
US3517879A
Cited
US3462590A
Cited
US3521041A
Cited
US3521042A
Cited
US3610901A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |