Patent FR2171909B1 successfully refreshed from Google Patents.
US4510440A
Expired / Lapsed
US
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Methods and apparatus for frequency response analysis
Assignee: Mobrey Group Ltd
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Filing: 1982-12-01
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Granted: 1985-04-09
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Expires: 2002-12-01
Abstract
Abstract In a heterodyning arrangement to enable frequency response testing of a system at a high frequency F using a digital correlator capable of operation at a lower frequency F/h, an offset signal is generated at a frequency F(h-1)/h and multiplied with the output signal of the system under test. Two heterodynes result: a wanted signal at a frequency F/h, and an unwanted image signal at F(2h-1)/h. The value of h is selectable independently of a divisor N which controls derivation of the test frequency F from a frequency synthesizer operating at a frequency NF. Thus the frequency of the image signal can be arranged to avoid spurious non-zero responses in the digital correlation process at frequencies related to N.
Inventors
- 👤 Alan Ryder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:09
CPC Classifications
G; G01; G01R; G01R23/00; G01R23/16
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
109 words
A method for testing the response of a system to an input signal at a frequency F using a correlator capable of operating at a lower frequency F/h, where h is a number greater than 1, comprising the steps of: generating a first signal at said frequency F; generating a second signal at a frequency F/h; generating a third signal at a frequency F(h-1)/h; applying said first signal to the system under test; multiplying the output signal from the system by the third signal to produce a product signal; and comparing the product signal in the correlator with the second signal to analyze system response to said input signal.
Claim 2
Independent Claim
109 words
A method for testing the response of a system to an input signal at a frequency F using a correlator capable of operating at a lower frequency F/h, where h is a number greater than 1, comprising the steps of: generating a first signal at said frequency F; generating a second signal at a frequency F/h; generating a third signal at a frequency F(h-1)/h; applying said first signal to the system under test; multiplying the output signal from the system by the third signal to produce a product signal; and comparing the product signal in the correlator with the second signal to analyze system response to said input signal.
Claim 3
Dependent Claim
30 words
A method according to claim 1, wherein said second signal is generated with a divide-by-h divider and said third signal is generated with an inverted carry signal from said divider.
Claim 4
Dependent Claim
82 words
A method according to claim 2, including the step of generating an initial signal at a frequency NF, where N is a number greater than 1 and different from h; and wherein said first signal is generated from said initial signal with a divide-by-N divider; said second signal is generated from said initial signal with said divide-by-h divider and a divide-by-N divider; and said third signal is generated from said inverted carry signal with a divide-by-N divider clocked at said frequency NF.
Claim 5
Dependent Claim
115 words
Apparatus for testing the response of a system to an input signal at a frequency F using a correlator capable of operating at a lower frequency F/h, where h is a number greater than 1, comprising: means for generating a first signal at said frequency F; means for generating a second signal at a frequency F/h; means for generating a third signal at a frequency F(h-1)/h; and means for multiplying the output signal from the system under test by the third signal while the first signal is applied thereto to produce a product signal; said correlator being arranged to compare the product signal with the second signal for analyzing system response to said input signal.
Claim 6
Dependent Claim
115 words
Apparatus for testing the response of a system to an input signal at a frequency F using a correlator capable of operating at a lower frequency F/h, where h is a number greater than 1, comprising: means for generating a first signal at said frequency F; means for generating a second signal at a frequency F/h; means for generating a third signal at a frequency F(h-1)/h; and means for multiplying the output signal from the system under test by the third signal while the first signal is applied thereto to produce a product signal; said correlator being arranged to compare the product signal with the second signal for analyzing system response to said input signal.
Claim 7
Dependent Claim
38 words
Apparatus according to claim 4, including a divide-by-h divider arranged to generate said second signal, and means for inverting a carry signal from said divider, said means for generating said third signal being responsive to said inverting means.
Claim 8
Dependent Claim
88 words
Apparatus according to claim 5, wherein: said means for generating said first signal comprises means arranged to generate an initial signal at a frequency NF, where N is a number greater than 1 and and different from h, and a divide-by-N divider; said means for generating said second signal comprises said divide-by-h divider coupled to receive said initial signal, and a divide-by-N divider; and said means for generating said third signal comprises a divide-by-N divider coupled to receive the inverted carry signal and clocked at the frequency NF.
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) | 1988-04-08 | 1988-10-08 | 1989-04-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-08 | 1992-10-08 | 1993-04-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-08 | 1996-10-08 | 1997-04-09 | $7700.00 | Window Closed / Lapsed |