US3816729A
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Real time fourier transformation apparatus
Assignee: Raytheon Co
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Filing: 1971-11-24
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Granted: 1974-06-11
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Expires: 1991-11-24
Abstract
Abstract An apparatus for performing real-time Fourier transformation of a time varying signal by taking successive digital samples in a shift register means and repeatedly transforming preselected pairs of said samples as the samples are progressively shifted down the register. The successive samples are ordered in the register in a binary sequence from 0 to 2n-1 while the pairs are selected when the binary distance between them is equal to 2n m, m being the transformation number, each pair Xa,m, Xb,m being related to its transformed magnitude Xa,m 1 and Xb,m 1 by the relations
Inventors
- 👤 G Works
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:29
CPC Classifications
G; G06; G06F; G06F17/00; G06F17/10; G06F17/14; G06F17/141; G06F17/142
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
197 words
An apparatus for transforming of digitized time varying samples of a signal into a substantially corresponding Fourier frequency distribution comprising: serial delay storage means having an input and an output port And ports intermediate the delay means for receiving the digitized samples arranged in order of succession at the input port; arithmetic means for transforming pairs or said samples and for transforming the succeeding transformed samples, i.e., Xa,m, Xb,m such that: Xa,m 1 Xa,m + Xb,mej Xb,m 1 Xa,m - Xb,mej where phi is the radian value of the position sequence order of the sample and j square root -1; means for extracting the said sample and transformed sample pairs, i.e., Xa,m, Xb,m from ports along the serial delay storage means and for applying them to the arithmetic means; means for returning the transformed samples, i.e., Xa,m 1, Xb,m 1 from the arithmetic means to their original position order of succession in the serial delay storage means; and means for propagating the digitized samples and transformed samples in the serial delay storage means between the input and output ports such that each sample and the succeeding transformed samples are extracted and transformed a predetermined number of times.
Claim 2
Independent Claim
197 words
An apparatus for transforming of digitized time varying samples of a signal into a substantially corresponding Fourier frequency distribution comprising: serial delay storage means having an input and an output port And ports intermediate the delay means for receiving the digitized samples arranged in order of succession at the input port; arithmetic means for transforming pairs or said samples and for transforming the succeeding transformed samples, i.e., Xa,m, Xb,m such that: Xa,m 1 Xa,m + Xb,mej Xb,m 1 Xa,m - Xb,mej where phi is the radian value of the position sequence order of the sample and j square root -1; means for extracting the said sample and transformed sample pairs, i.e., Xa,m, Xb,m from ports along the serial delay storage means and for applying them to the arithmetic means; means for returning the transformed samples, i.e., Xa,m 1, Xb,m 1 from the arithmetic means to their original position order of succession in the serial delay storage means; and means for propagating the digitized samples and transformed samples in the serial delay storage means between the input and output ports such that each sample and the succeeding transformed samples are extracted and transformed a predetermined number of times.
Claim 3
Independent Claim
163 words
An apparatus for performing a real-time Fourier transformation of a time varying signal comprising: means for forming N successive digital signal samples, the successive samples being ordered in sequence; shift register means for receiving the successive digital samples; means for extracting N/2 pairs of said samples and of their succeeding transformed sample pairs, i.e., Xa,m, Xb,m from the shift register means; means for transforming each extracted sample pair and succeeding transformed sample pair, i.e., Xa,m, Xb,m such that: Xa,m 1 Xa,m + Xb,mej Xb,m 1 Xa,m - Xb,mej where phi is the radian value of the position sequence order of the sample and j is equal to Square Root -1; means for returning the N transformed samples, i.e., Xa,m 1, Xb, m 1 to their original position order of succession in the shift register means; and means for shifting the digital samples in the shift register means such that each sample and its succeeding transformed sample is extracted and transformed n log2N times.
Claim 4
Independent Claim
163 words
An apparatus for performing a real-time Fourier transformation of a time varying signal comprising: means for forming N successive digital signal samples, the successive samples being ordered in sequence; shift register means for receiving the successive digital samples; means for extracting N/2 pairs of said samples and of their succeeding transformed sample pairs, i.e., Xa,m, Xb,m from the shift register means; means for transforming each extracted sample pair and succeeding transformed sample pair, i.e., Xa,m, Xb,m such that: Xa,m 1 Xa,m + Xb,mej Xb,m 1 Xa,m - Xb,mej where phi is the radian value of the position sequence order of the sample and j is equal to Square Root -1; means for returning the N transformed samples, i.e., Xa,m 1, Xb, m 1 to their original position order of succession in the shift register means; and means for shifting the digital samples in the shift register means such that each sample and its succeeding transformed sample is extracted and transformed n log2N times.
Claim 5
Dependent Claim
72 words
An apparatus according to claim 2 wherein: the shift register means has a register capacity at least equal to qN where q is the number of digits in each sample; the means for extracting N/2 sample pairs and their succeeding transformed sample pairs, i.e., Xa,m, Xb,m including means for extracting pairs having a distance d between the samples of each pair such that d 2n m, where m is the transformation number.
Claim 6
Dependent Claim
11 words
An apparatus according to claim 2 wherein: phi (2 pi i/2m)
Claim 7
Independent Claim
189 words
An apparatus for performing a real-time Fourier transformation of a time varying signal comprising: means for forming N successive digital signal samples of q digits per sample, the successive samples being ordered in sequence from 0 to N-1; shift register means adapted to receive the successive digital samples and having a register capacity at least equal to qN; means for extracting N/2 pairs of samples, i.e., Xa,m, Xb,m from the shift register means and including means for extracting only pairs having a distance d between the digits of the pair of d 2n m, where m is the transformation number and n log2N; means for transforming each extracted digit pair, i.e., Xa,m, Xb,m such that: Xa,m 1 Xa,m + Xb,mej Xb,m 1 Xa,m - Xb,mej where phi is the radian value equal to (2 pi i/2m) and j is equal to Square Root -1; means for returning the N/2 transformed pairs, i.e., Xa,m 1, Xb, m 1 to their original position order of succession in the shift register means; and means for shifting the digital samples in the shift register means such that each sample is transformed n times.
Claim 8
Independent Claim
189 words
An apparatus for performing a real-time Fourier transformation of a time varying signal comprising: means for forming N successive digital signal samples of q digits per sample, the successive samples being ordered in sequence from 0 to N-1; shift register means adapted to receive the successive digital samples and having a register capacity at least equal to qN; means for extracting N/2 pairs of samples, i.e., Xa,m, Xb,m from the shift register means and including means for extracting only pairs having a distance d between the digits of the pair of d 2n m, where m is the transformation number and n log2N; means for transforming each extracted digit pair, i.e., Xa,m, Xb,m such that: Xa,m 1 Xa,m + Xb,mej Xb,m 1 Xa,m - Xb,mej where phi is the radian value equal to (2 pi i/2m) and j is equal to Square Root -1; means for returning the N/2 transformed pairs, i.e., Xa,m 1, Xb, m 1 to their original position order of succession in the shift register means; and means for shifting the digital samples in the shift register means such that each sample is transformed n times.
Claim 9
Dependent Claim
69 words
An apparatus according to claim 2 wherein the means for transforming each extracted sample pair comprise: a succession of n logic modules each of which executes the two-point transform Xa,m 1 Xa,m + Xb,mej Xb,m 1 Xa,m - Xb,mej and to which are applied corresponding ones of the N/2 sample pairs, each logic module further being coupled to predetermined sample positions along the extent of the shift register means.
Claim 10
Dependent Claim
71 words
An apparatus according to claim 5 wherein the means for transforming each extracted digit pair comprise: a succession of n logic modules of each of which executes the two-point transform Xa,m 1 Xa,m + Xb,mej Xb,m 1 Xa,m - Xb, mej and to which are applied corresponding ones of the N/2 sample pairs, each logic module further being coupled to predetermined sample positions along the extent of the shift register means.
Claim 11
Dependent Claim
77 words
An apparatus according to claim 2 wherein the transformation means comprise: a data bus common to pre-selected sample positions along the extent of the shift register means; means for time multiplexing the contents of the pre-selected sample positions onto the data bus and for demultiplexing the contents from the data bus to the pre-selected sample positions; and logic means for transforming data on the bus into transformed data and returning said transformed data to the data bus.
Claim 12
Dependent Claim
77 words
An apparatus according to claim 5 wherein the transformation means comprise: a data bus common to pre-selected sample positions along the extent of the shift register means; means for time multiplexing the contents of the pre-selected sample positions onto the data bus and for demultiplexing the contents from the data bus to the pre-selected sample positions; and logic means for transforming data on the bus into transformed data and returning said transformed data to the data bus.
Claim 13
Dependent Claim
90 words
A transform system comprising: a plurality of serially coupled computational stages supplied with an input data train; means for feeding the data output of each of said stages except the last to the data input of a succeeding stage; at least one of said stages having arithmetic means and data storage means; and switching means for cyclically connecting the input and output of said storage means to said arithmetic means and disconnecting said input and output of said storage means from said arithmetic means in accordance with a predetermined program.
Claim 14
Dependent Claim
90 words
A transform system comprising: a plurality of serially coupled computational stages supplied with an input data train; means for feeding the data output of each of said stages except the last to the data input of a succeeding stage; at least one of said stages having arithmetic means and data storage means; and switching means for cyclically connecting the input and output of said storage means to said arithmetic means and disconnecting said input and output of said storage means from said arithmetic means in accordance with a predetermined program.
Claim 15
Dependent Claim
66 words
The transform system in accordance with claim 10; and means comprising said switching means and a timing means feeding said switching means for alternately connecting the output of said storage means to said arithmetic means and to the succeeding stage and alternately connecting the input of said storage means to an output of said arithmetic means and to a data input channel from said preceding stage.
Claim 16
Dependent Claim
66 words
The transform system in accordance with claim 11 wherein said arithmetic means has first and second inputs and said switching means alternately connects the output of said data storage means to said first input of said arithmetic means and to a data output channel feeding the succeeding stage and alternately connects said second input of said arithmetic means to said data input from said preceding stage.
Claim 17
Dependent Claim
25 words
The transForm system in accordance with claim 12 wherein said switching means alternately connects a second output of said arithmetic means to the succeeding stage.
Claim 18
Dependent Claim
58 words
The transform system in accordance with claim 13 wherein said arithmetic means performs an algebraic summation of pairs of samples and further comprising: means for weighting at least one sample of each pair in accordance with a predetermined code; and means for feeding said weighting means with weighting signals for varying said weighting in accordance with said code.
Claim 19
Dependent Claim
19 words
The transform system in accordance with claim 14 wherein said weighting is varied in accordance with a trigonometric function.
Claim 20
Dependent Claim
59 words
The transform system in accordance with claim 10 further comprising: means comprising said arithmetic means for producing an output data train comprising the algebraic sum of pairs of data samples; and means coupled to said means for producing an output data train for weighting at least one sample of each of said pairs in accordance with a predetermined program.
Claim 21
Dependent Claim
22 words
The transform system in accordance with claim 16 wherein said weighting means comprises means for generating a time varying sequence of weights.
Claim 22
Dependent Claim
24 words
The transform system in accordance with claim 10 wherein at least a plurality of said stages each have arithmetic means and data storage means.
Claim 23
Dependent Claim
54 words
The transform system in accordance with claim 18 further comprising: means comprising said arithmetic means for producing an output data train comprising the algebraic sum of pairs of data samples; and means coupled to said arithmetic means for weighting at least one sample of each of said pairs in accordance with a predetermined program.
Claim 24
Dependent Claim
22 words
The transform system in accordance with claim 19 wherein said weighting means comprises means for generating a time varying sequence of weights.
Claim 25
Dependent Claim
112 words
A transform system comprising a plurality of serially coupled computational stages, at least some of said stages producing at least a portion of a transform, each of said stages comprising: means for computing the algebraic sum of pairs of data samples; means for storing data; switching means within each of said stages for cyclically feeding portions of the output data from said computing means to said data storing means and other portions of said output data from said computing means to another one of said stages; and means coupled to said computing means for weighting at least one sample of at least some pairs of samples in accordance with a predetermined program.
Claim 26
Dependent Claim
112 words
A transform system comprising a plurality of serially coupled computational stages, at least some of said stages producing at least a portion of a transform, each of said stages comprising: means for computing the algebraic sum of pairs of data samples; means for storing data; switching means within each of said stages for cyclically feeding portions of the output data from said computing means to said data storing means and other portions of said output data from said computing means to another one of said stages; and means coupled to said computing means for weighting at least one sample of at least some pairs of samples in accordance with a predetermined program.
Claim 27
Dependent Claim
19 words
The transform system in accordance with claim 21 in which all of said stages perform a substantially Fourier transform.
Claim 28
Dependent Claim
21 words
The transform system in accordance with claim 22 wherein at least one said sample of each pair is weighted as unity.
Claim 29
Dependent Claim
19 words
The transform system in accordance with claim 21 wherein said samples are weighted in accordance with a trigonometric function.
Claim 30
Dependent Claim
21 words
The transform system in accordance with claim 24 wherein said weighting means further comprises: means for storing said trigonometric function weights.
Claim 31
Dependent Claim
32 words
The transform system in accordance with claim 25 wherein said weighting is cyclically varied over an N sample period where N is the number of data samples in a block of data.
Claim 32
Dependent Claim
42 words
The transform system in accordance with claim 26 wherein said means for storing data has a storage capacity substantially equal to 2n m where n log2N and m is the transform number of the stage in which said storage means is located.
Claim 33
Dependent Claim
26 words
The transform system in accordance with claim 27 wherein N for at least one stage is different from N for a preceding and/or a succeeding stage.
Claim 34
Dependent Claim
32 words
The transform system in accordance with claim 28 wherein the N of at least one stage differs substantially by a factor of two from the N of a preceding and/or succeeding stage.
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) | 1977-06-10 | 1977-12-10 | 1978-06-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-10 | 1981-12-10 | 1982-06-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-10 | 1985-12-10 | 1986-06-11 | $7700.00 | Window Closed / Lapsed |