US3641445A
Expired / Lapsed
US
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Frequency analyzer
Assignee: TDK Micronas GmbH
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Filing: 1970-07-23
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Granted: 1972-02-08
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Expires: 1990-07-23
Abstract
Abstract A frequency analyzer is provided wherein real-time, narrow bandpass filters having large dynamic range are synthesized for each frequency. Each filter consists of a local clock driven synchronous detector followed by a simple integrating circuit. Large dynamic range is achieved through the use of a two-state switching device as the synchronous detector. Since the output of the synchronous detector depends on the phase relationship between the input signal and the local clock, two phasequadrature filters are provided for each frequency. The output from the filter pair is processed in a manner that yields a signal whose amplitude is independent of the input signal-local clock phase relationship.
Inventors
- 👤 Joseph A Green
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:45
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/02; G01S13/50; G01S13/58; G01S13/64; G01R; G01R23/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
97 words
A frequency discriminator comprising: two phase-quadrature filters coupled to an input signal for converting said input signal into two phase-quadrature components; means for generating two phase-quadrature square waves; a first and second multiplying means each coupled to one of said square waves and one of said phase-quadrature filter outputs for generating outputs each proportional to the amplitude of corresponding phase-quadrature filter outputs; and an arithmetic adder coupled to the outputs of said first and second multiplier means, said arithmetic adder having an output whose amplitude and fundamental frequency are independent of the phase of said input signal.
Claim 2
Dependent Claim
97 words
A frequency discriminator comprising: two phase-quadrature filters coupled to an input signal for converting said input signal into two phase-quadrature components; means for generating two phase-quadrature square waves; a first and second multiplying means each coupled to one of said square waves and one of said phase-quadrature filter outputs for generating outputs each proportional to the amplitude of corresponding phase-quadrature filter outputs; and an arithmetic adder coupled to the outputs of said first and second multiplier means, said arithmetic adder having an output whose amplitude and fundamental frequency are independent of the phase of said input signal.
Claim 3
Dependent Claim
87 words
A frequency discriminator according to claim 1 where each of said phase-quadrature filters includes: a source of a reference signal each in phase quadrature and having the same preselected frequency; a synchronous detector coupled to said reference signal and said input signal for generating an output containing sum and difference frequencies; and an integrator circuit coupled to the output of said synchronous detector for eliminating the sum-frequency component and averaging the difference frequency component over a time period equivalent to the time constant of the integrator circuit.
Claim 4
Dependent Claim
61 words
A frequency discriminator according to claim 1 further comprising: means coupled to said input signal for eliminating signal components corresponding to higher order harmonics of the frequency band of interest; and means coupled to said arithmetic adder for eliminating higher order harmonics and producing a sinusoidal output having a fundamental frequency and amplitude independent of the phase of said input signal.
Claim 5
Dependent Claim
49 words
A frequency discriminator according to claim 1 including: a plurality of pairs of phase-quadrature filters wherein a local clock associated with each pair is tuned to a different frequency; and a commutator for coupling the outputs of each of said plurality of phase-quadrature filters sequentially to said summing means.
Claim 6
Independent Claim
137 words
A method of spectrum analysis comprising the steps of: comparing the frequency of an input signal with two phase-quadrature reference signals, each of said reference signals having the same frequency; generating a signal containing components having frequencies equal to the sum and difference frequencies of said input signal and each of said reference signals, the amplitude of said signal being a function of the phase difference between said input signal and each of said reference signals; eliminating each sum-frequency component; averaging each difference frequency component over a predetermined period of time; generating two phase-quadrature square waves; multiplying each of said average difference frequency component by a different one of said phase-quadrature square waves; and summing the multiplied signals to produCe an output signal having an amplitude and functional frequency independent of the phase of said input signal.
Claim 7
Independent Claim
137 words
A method of spectrum analysis comprising the steps of: comparing the frequency of an input signal with two phase-quadrature reference signals, each of said reference signals having the same frequency; generating a signal containing components having frequencies equal to the sum and difference frequencies of said input signal and each of said reference signals, the amplitude of said signal being a function of the phase difference between said input signal and each of said reference signals; eliminating each sum-frequency component; averaging each difference frequency component over a predetermined period of time; generating two phase-quadrature square waves; multiplying each of said average difference frequency component by a different one of said phase-quadrature square waves; and summing the multiplied signals to produCe an output signal having an amplitude and functional frequency independent of the phase of said input signal.
Claim 8
Dependent Claim
23 words
A method according to claim 5 further comprising the step of eliminating third or higher order harmonics from said input and output signals.
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) | 1975-02-07 | 1975-08-09 | 1976-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-02-07 | 1979-08-09 | 1980-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-02-07 | 1983-08-09 | 1984-02-08 | $7700.00 | Window Closed / Lapsed |