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US4686457A
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Method for measuring a signal's frequency components
Assignee: Verigy Singapore Pte Ltd
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Filing: 1986-08-01
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Granted: 1987-08-11
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Expires: 2006-08-01
Abstract
Abstract A method is presented for accurately measuring an input signal's frequency components and the amplitude of those components. This is done by digitizing an input signal, passing it through a window, converting it into the frequency domain, and using the Fourier transform of the window to remove the effects of window from the input signal converted into the frequency domain.
Inventors
- 👤 Takuo Banno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:59
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/16
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
68 words
A method comprising the steps of: sampling and digitizing an input signal; multiplying said sampled and digitized input signal by a window having a known fourier transform; obtaining the digital fourier transform of said input signal multiplied by said window; selecting two spectral components; fitting the fourier transform of said window to said selected spectral components; and determining the frequency components of said input signal from said fitting.
Claim 2
Independent Claim
68 words
A method comprising the steps of: sampling and digitizing an input signal; multiplying said sampled and digitized input signal by a window having a known fourier transform; obtaining the digital fourier transform of said input signal multiplied by said window; selecting two spectral components; fitting the fourier transform of said window to said selected spectral components; and determining the frequency components of said input signal from said fitting.
Claim 3
Dependent Claim
14 words
A method as in claim 1 wherein more than two spectral components are selected.
Claim 4
Dependent Claim
45 words
A method as in claim 1 wherein said input signal has one predominate frequency and wherein determining the frequency components of the input signal involves identifying the frequency where the fourier transform of the window fitted to said selected spectral components has its maximum amplitude.
Claim 5
Dependent Claim
52 words
A method as in claim 1 wherein the steps of fitting and determining further comprise: using the difference in amplitude between said two spectral components and the inverse of y(g) to determine g; and determining the frequency of said input signal by subtracting said g from the frequency of a spectral component.
Claim 6
Dependent Claim
34 words
A method as in claim 4 further comprising the steps of: determining the amplitude of H(g) at said g; dividing the amplitude of said spectral component by the amplitude of H(g) at said g.
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) | 1990-08-10 | 1991-02-09 | 1991-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-10 | 1995-02-09 | 1995-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-10 | 1999-02-09 | 1999-08-11 | $7700.00 | Window Closed / Lapsed |