US3568107A
Expired / Lapsed
US
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Method and apparatus for effecting tapped delay line synthesis of large time bandwidth filters
Assignee: Individual
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Filing: 1969-09-09
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Granted: 1971-03-02
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Expires: 1989-09-09
Abstract
Abstract The present invention comprehends a method and apparatus for the design of large time bandwidth product linear filters by tapped delay line filter synthesis techniques. A periodic transfer function is selected which has a linear time delay characteristic and an amplitude versus frequency characteristic which, in combination with like transfer functions in proper phase relationship produces a filter with a constant resultant amplitude versus frequency characteristic and a linear time delay characteristic. A plurality of sequences of pulses are generated by a tapped delay line. The number of pulses in each sequence is equal to the number of Fourier harmonics of the selected periodic transfer function. They are weighted with appropriate Fourier coefficients and are combined to form a plurality of synthesized periodic transfer functions that conform to the selected transfer function. The synthesized periodic transfer functions are divided into constituent components defined by various frequency bands (or periods). The constituent components are relatively delayed and recombined to effect the composite filter having an extremely large time bandwidth product.
Inventors
- 👤 Ronald D Haggarty
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:40
CPC Classifications
H; H03; H03H; H03H17/00; H03H17/02; H03H17/06
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
200 words
The method of synthesizing large time bandwidth product filters by means of tapped delay line filter synthesis comprising the steps of: selecting a discrete periodic transfer function, said transfer function having an amplitude characteristic that is a complete cycle of (1 + cosine) function over a portion of said period, a minimal amplitude over the remaining portion of the period, a characteristic effective to produce a constant resultant amplitude when combined with an identical function that has been properly frequency shifted and added in proper phase relationship, and a linear time delay characteristic; generating by a tapped delay line, at least three sequences of pulses, each said sequence having a number of pulses equal to the number of Fourier harmonics that constitute said transfer functions; weighting said pulses with the Fourier phase and amplitude coefficients characteristic of said transfer function; summing said weighted pulses in appropriate order and time sequence to synthesize at least three of said transfer function; dividing each said synthesized transfer function into constituent components defined by various frequency bands; effecting relative delays of said constituent components; and recombining said delayed constituent components so as to achieve the total transfer function of the large time-bandwidth product filter.
Claim 2
Independent Claim
200 words
The method of synthesizing large time bandwidth product filters by means of tapped delay line filter synthesis comprising the steps of: selecting a discrete periodic transfer function, said transfer function having an amplitude characteristic that is a complete cycle of (1 + cosine) function over a portion of said period, a minimal amplitude over the remaining portion of the period, a characteristic effective to produce a constant resultant amplitude when combined with an identical function that has been properly frequency shifted and added in proper phase relationship, and a linear time delay characteristic; generating by a tapped delay line, at least three sequences of pulses, each said sequence having a number of pulses equal to the number of Fourier harmonics that constitute said transfer functions; weighting said pulses with the Fourier phase and amplitude coefficients characteristic of said transfer function; summing said weighted pulses in appropriate order and time sequence to synthesize at least three of said transfer function; dividing each said synthesized transfer function into constituent components defined by various frequency bands; effecting relative delays of said constituent components; and recombining said delayed constituent components so as to achieve the total transfer function of the large time-bandwidth product filter.
Claim 3
Dependent Claim
52 words
The method of synthesizing large time bandwidth product filters defined in claim 1 wherein said discrete periodic transfer function amplitude is 1 + cosine M pi and the time delay is in the nonzero amplitude part of each period (Wp period). The nonzero part of said period being amplitude-linear time delay filter.
Claim 4
Dependent Claim
145 words
A large time bandwidth product signal filter comprising means for generating from one input pulse of plurality of sequences of pulses in response to each said input function, each said sequence having a number of pulses equal to the number of Fourier harmonics in a discrete periodic transfer function, means for weighting the pulses in each said sequence with the Fourier phaSe and amplitude coefficients characteristic of said transfer function, means for summing said weighted pulses in appropriate order and time sequence to synthesize a plurality of said transfer functions, means for dividing each said synthesized transfer function into constituent components defined by various frequency bands, means for effecting relative delays of said constituent components, and means for recombining said delayed constituent components such that the resultant signal is the pulse response of the desired large time bandwidth product -constant amplitude -linear time delay filter.
Claim 5
Dependent Claim
145 words
A large time bandwidth product signal filter comprising means for generating from one input pulse of plurality of sequences of pulses in response to each said input function, each said sequence having a number of pulses equal to the number of Fourier harmonics in a discrete periodic transfer function, means for weighting the pulses in each said sequence with the Fourier phaSe and amplitude coefficients characteristic of said transfer function, means for summing said weighted pulses in appropriate order and time sequence to synthesize a plurality of said transfer functions, means for dividing each said synthesized transfer function into constituent components defined by various frequency bands, means for effecting relative delays of said constituent components, and means for recombining said delayed constituent components such that the resultant signal is the pulse response of the desired large time bandwidth product -constant amplitude -linear time delay filter.
Claim 6
Dependent Claim
31 words
A large time bandwidth product filter as defined in claim 3 wherein said means for generating a sequence of pulses comprises nondispersive delay line having a plurality of equally spaced taps.
Claim 7
Dependent Claim
23 words
A large time bandwidth product filter as defined in claim 4 wherein said means for weighting pulses comprises a complex resistive weighting network.
Claim 8
Dependent Claim
58 words
A large time bandwidth product filter as defined in claim 2 wherein said discrete periodic transfer function has a complete cycle within a given period, minimal amplitude over a portion of said period, a characteristic effective to produce a constant resultant amplitude when combined with an identical function in proper phase relationship, and a linear time delay characteristic.
Claim 9
Dependent Claim
39 words
A large time bandwidth product generator as defined in claim 2 wherein said discrete periodic transfer function amplitude is 1 + cos M pi within portion of each period and minimal over the remaining portions of said period (Wp).
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) | 1974-03-01 | 1974-08-31 | 1975-03-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-01 | 1978-08-31 | 1979-03-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-01 | 1982-08-31 | 1983-03-02 | $7700.00 | Window Closed / Lapsed |