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US4760549A
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US
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In line testing device for a circuit calculating the discrete Fourier transform and a circuit comprising such a device
Assignee: THOMSN-CSF 173 B1 HAUSSMANN 75008 PARIS
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Filing: 1985-10-24
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Granted: 1988-07-26
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Expires: 2005-10-24
Abstract
Abstract An in line testing device for a circuit calculating discrete Fourier transform as well as a circuit including such a device. The device has a processor for calculating the discrete Fourier transform and a processor effecting in line checking of the calculation of the discrete Fourier transform. The check uses Parseval's theorem: ##EQU1##
Inventors
- 👤 Arnaud du Chene
- 👤 Brigitte Delalande
- 👤 Thierry Mariaux
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 04:04
CPC Classifications
G; G06; G06F; G06F17/00; G06F17/10; G06F17/14; G06F17/141
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
85 words
An apparatus for checking a discrete fourier transform, comprising: means for calculating the two terms of Parseval's equation with one term based on samples and the other term based on Fourier coefficients of the fourier transform; subtractor means for subtracting one of said terms from the other of said terms to produce a result; and comparator means, connected to said subtractor means to receive said result, for comparing said result with a tolerance and producing an indication when said result is greater than said tolerance.
Claim 2
Independent Claim
85 words
An apparatus for checking a discrete fourier transform, comprising: means for calculating the two terms of Parseval's equation with one term based on samples and the other term based on Fourier coefficients of the fourier transform; subtractor means for subtracting one of said terms from the other of said terms to produce a result; and comparator means, connected to said subtractor means to receive said result, for comparing said result with a tolerance and producing an indication when said result is greater than said tolerance.
Claim 3
Dependent Claim
30 words
An apparatus as in claim 1 further comprising means for calculating said discrete fourier transform; and a data bus transmitting values from said fourier transform calculating device to said calculating.
Claim 4
Dependent Claim
56 words
An apparatus as in claim 1 wherein said calculating means includes: squaring means for calculating a squared value of each said term; summing means for summing said squares of respective terms to produce two summed terms; and dividing means for dividing one of said summed terms by a number of squares making up said one sum.
Claim 5
Dependent Claim
59 words
The apparatus as in claim 3 wherein said squaring means comprises: means for calculating an absolute value of one of said terms of said discrete fourier transform; and multiplying means, having two inputs each connected to an output of said absolute value means, for multiplying said inputs to produce a square of said output of said absolute value means.
Claim 6
Dependent Claim
13 words
An apparatus as in claim 3 wherein said summing means comprises an accumulator.
Claim 7
Dependent Claim
24 words
An apparatus as in claim 1 further comprising alarm means, coupled to said comparator means, for producing an alarm in response to said indication.
Claim 8
Independent Claim
89 words
An apparatus for checking a discrete fourier transform comprising: means for calculating two summations based on terms including said fourier transform and values before fourier transforming, including a first summation of: ##EQU10## where X(k) is a fourier transform of x(n); subtractor means for subtracting one of said summations from the other of said summations to produce a result; and comparator means connected to said subtractor means to receive said result for comparing said result with a tolerance and producing an indication when said result is greater than said tolerance.
Claim 9
Independent Claim
89 words
An apparatus for checking a discrete fourier transform comprising: means for calculating two summations based on terms including said fourier transform and values before fourier transforming, including a first summation of: ##EQU10## where X(k) is a fourier transform of x(n); subtractor means for subtracting one of said summations from the other of said summations to produce a result; and comparator means connected to said subtractor means to receive said result for comparing said result with a tolerance and producing an indication when said result is greater than said tolerance.
Claim 10
Dependent Claim
38 words
An apparatus as in claim 7 wherein said calculating means includes means for calculating an absolute value of said terms; and a multiplier connected to an output of said absolute value calculating means for squaring said absolute value.
Claim 11
Dependent Claim
24 words
An apparatus as in claim 8 wherein said calculating means comprises dividing means for dividing an output of said multiplier by a predetermined value.
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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) | 1991-07-26 | 1992-01-25 | 1992-07-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-26 | 1996-01-25 | 1996-07-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-26 | 2000-01-25 | 2000-07-26 | $7700.00 | Window Closed / Lapsed |