US4060850A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Beam former using bessel sequences
Assignee: United States Department of the Navy
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Filing: 1977-04-25
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Granted: 1977-11-29
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Expires: 1997-04-25
Abstract
Abstract A beam former, to be used with a circular array of N receiving elements, N>/=3, comprising a set of N discrete Fourier transform (DFT) devices, each one connected to one of the receiving elements, for taking a temporal discrete Fourier transform of the signals at each of the N receiving elements. Means are connected to the array of DFT devices, for connecting sequentially to each of the N devices. A reference function generator generates the sequence of terms <IMAGE> (1) where the argument x is equal to the number of wavelengths in the circumference of the circular array at the frequency being processed, and M is several times greater than x. A means connected to the connecting means and to the reference function generator circularly convolves the signals, for example, acoustic signals, received from the connecting means and the function generator. The beam former may further comprise means connected to the convolving means for displaying the inverse discrete Fourier transform, and therefore the beam pattern.
Inventors
- 👤 Jeffrey M. Speiser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:43
CPC Classifications
H; H01; H01Q; H01Q3/00; H01Q3/26; G; G06; G06F; G06F17/00; G06F17/10; G06G; G06G7/00; G06G7/12; G06G7/19; G06G7/1921; G10; G10K; G10K11/00; G10K11/18; G10K11/26; G10K11/34; G10K11/341; G10K11/343
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
130 words
A beam former, to be used with a circular array of N signal receiving elements, N≧3, comprising: an array of N discrete Fourier transform (DFT) devices, each one connected to one of the receiving elements, for taking a temporal discrete Fourier transform of the signals at each of the N receiving elements; means connected to the array of DFT devices, for connecting sequentially to each of the N devices; a reference function generator, which generates the sequence of terms ##EQU16## where the argument x is equal to the number of wavelengths in the circumference of the circular array at the frequency being processed; and means connected to the connecting means and to the reference function generator, for circularly convolving the signals received from the connecting means and the function generator.
Claim 2
Dependent Claim
130 words
A beam former, to be used with a circular array of N signal receiving elements, N≧3, comprising: an array of N discrete Fourier transform (DFT) devices, each one connected to one of the receiving elements, for taking a temporal discrete Fourier transform of the signals at each of the N receiving elements; means connected to the array of DFT devices, for connecting sequentially to each of the N devices; a reference function generator, which generates the sequence of terms ##EQU16## where the argument x is equal to the number of wavelengths in the circumference of the circular array at the frequency being processed; and means connected to the connecting means and to the reference function generator, for circularly convolving the signals received from the connecting means and the function generator.
Claim 3
Dependent Claim
27 words
The beam former according to claim 1, further comprising: means connected to the convolving means, for displaying the inverse discrete Fourier transform, and therefore the beam pattern.
Claim 4
Dependent Claim
17 words
The beam former according to claim 1, wherein: the receiving elements are elements for receiving acoustic signals.
Claim 5
Dependent Claim
116 words
The beam former according to claim 1, wherein the reference function generator comprises: means for generating the Bessel sequence J n (x), n=0, 1, . . . , N-1, where the argument x is equal to the number of acoustic wavelengths in the circumference of the array at the frequency being processed; a signal summer, one of whose inputs is the output of the generating means; a delay line, whose input is connected to the output of the summer; and an attenuator, whose input is connected to the output of the delay line and whose output is connected to the signal summer, the loop gain of the delay line and attenuator being slightly less than one.
Claim 6
Dependent Claim
26 words
The array according to claim 4, further comprising: means connected to the convolving means for displaying the beam pattern as a function of frequency versus azimuth.
Claim 7
Dependent Claim
83 words
The beam former according to claim 1, wherein the means for circularly convolving comprises: means connected to the connecting means, for taking the discrete Fourier transform of the N transformed signals; a multiplier, whose two inputs comprise the outputs of the reference function generator and of the DFT means, for multiplying the signals at its two inputs; and means whose input is connected to the output of the multiplier, for taking the inverse discrete Fourier transform of the signal received at its input.
Claim 8
Dependent Claim
22 words
The array according to claim 6, further comprising: means connected to the inverse DFT means for displaying the inverse discrete Fourier transform.
Claim 9
Dependent Claim
171 words
A beam former, to be used with a circular array of N signal receiving elements, N≧3, comprising: a partial chirp-Z transform (CZT) device, having N inputs connected to the N receiving elements, and N outputs, for taking the chirp-Z transform in one of the dimensions, temporal or spatial of signals at the receiving elements; a parallel-input CZT device, having N inputs connected to the N outputs of the partial CZT device, for taking the chirp-Z transform of the signals in the other dimension, spatial or temporal; a reference function generator, which generates the sequence of terms ##EQU17## where the argument x is equal to the number of wavelengths in the circumference of the circular array at the frequency being processed; and means connected to the parallel-input CZT device and to the reference function generator, for summing the signals received from the CZT device and the function generator; and means, whose input is connected to the output of the summing means, for performing an inverse discrete Fourier transform on its input signal.
Claim 10
Dependent Claim
171 words
A beam former, to be used with a circular array of N signal receiving elements, N≧3, comprising: a partial chirp-Z transform (CZT) device, having N inputs connected to the N receiving elements, and N outputs, for taking the chirp-Z transform in one of the dimensions, temporal or spatial of signals at the receiving elements; a parallel-input CZT device, having N inputs connected to the N outputs of the partial CZT device, for taking the chirp-Z transform of the signals in the other dimension, spatial or temporal; a reference function generator, which generates the sequence of terms ##EQU17## where the argument x is equal to the number of wavelengths in the circumference of the circular array at the frequency being processed; and means connected to the parallel-input CZT device and to the reference function generator, for summing the signals received from the CZT device and the function generator; and means, whose input is connected to the output of the summing means, for performing an inverse discrete Fourier transform on its input signal.
Claim 11
Dependent Claim
28 words
The beam former according to claim 8, further comprising: means connected to the inverse DFT means, for displaying the inverse discrete Fourier transform, and therefore the beam pattern.
Claim 12
Dependent Claim
17 words
The beam former according to claim 9, wherein: the receiving elements are elements for receiving acoustic signals.
Claim 13
Dependent Claim
118 words
The beam former according to claim 8, wherein the reference function generator comprises: means for generating the Bessel sequence J n (x), n=0, 1, . . . , N-1, where the argument x is equal to the number of acoustic wavelengths in the circumference of the array at the frequency being processed; a signal summer, one of whose inputs is the output of the generating means; a delay line, whose input is connected to the output of the summer; and an attenuator, whose input is connected to the output of the delay line and whose output is connected to the signal summer; the gain of the loop which includes the delay line and attenuator being less than one.
Claim 14
Dependent Claim
31 words
The array according to claim 11, further comprising: means connected to the inverse DFT means for displaying the inverse discrete Fourier transform, and therefore the beam pattern formed by the array.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-11-28 | 1981-05-30 | 1981-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-11-28 | 1985-05-30 | 1985-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-11-28 | 1989-05-30 | 1989-11-29 | $7700.00 | Window Closed / Lapsed |