US4091330A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit and method for demodulating a frequency modulated signal
Assignee: Ampex Corp
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Filing: 1977-09-15
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Granted: 1978-05-23
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Expires: 1997-09-15
Abstract
Abstract A new and improved circuit and method for demodulating a modulated signal. The circuit of this invention includes a multivibrator switchable from one state to another in response to transitions of a modulated frequency spectrum signal, time delay means coupled between an output terminal of the multivibrator and an input terminal thereof for switching the multivibrator to a second state after a time delay determined by the time delay means, and means for shorting the time delay means after the multivibrator switches state. Thus, the means for shorting out the time delay means allows the multivibrator to be substantially immediately receptive to the next succeeding transition of the input signal.
Inventors
- 👤 Tsuneyoshi Hidaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 16:45
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/02; H03D3/04
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
176 words
A circuit for demodulating a frequency modulated signal embodying a frequency spectrum signal modulated on a carrier signal, said circuit comprising: means for shaping the modulated signal into a series of voltage transitions having a pulse repetition rate proportional to that of the modulated signal; a multivibrator switchable to a first state in response to the voltage transitions, said multivibrator providing a square-wave output signal at a pulse repetition rate proportional to that of the voltage transitions; time delay means coupled between an output terminal of said multivibrator and an input terminal of said multivibrator for switching said multivibrator to a second state after a time delay determined by said time delay means; means coupled in parallel with said time delay means for shorting said time delay means after said multivibrator has been switched to said second state such that said multivibrator is substantially immediately receptive to the next succeeding voltage transition; and, means for integrating the square-wave output signal from said multivibrator so as to provide the frequency spectrum signal demodulated from the carrier signal.
Claim 2
Dependent Claim
176 words
A circuit for demodulating a frequency modulated signal embodying a frequency spectrum signal modulated on a carrier signal, said circuit comprising: means for shaping the modulated signal into a series of voltage transitions having a pulse repetition rate proportional to that of the modulated signal; a multivibrator switchable to a first state in response to the voltage transitions, said multivibrator providing a square-wave output signal at a pulse repetition rate proportional to that of the voltage transitions; time delay means coupled between an output terminal of said multivibrator and an input terminal of said multivibrator for switching said multivibrator to a second state after a time delay determined by said time delay means; means coupled in parallel with said time delay means for shorting said time delay means after said multivibrator has been switched to said second state such that said multivibrator is substantially immediately receptive to the next succeeding voltage transition; and, means for integrating the square-wave output signal from said multivibrator so as to provide the frequency spectrum signal demodulated from the carrier signal.
Claim 3
Dependent Claim
23 words
A circuit as in claim 1 further characterized by said means for shorting said time delay means being a unidirectional current flow device.
Claim 4
Dependent Claim
22 words
A circuit as in claim 2 further characterized by means for biasing said unidirectional current flow circuit device at a threshold potential.
Claim 5
Dependent Claim
43 words
A circuit as in claim 2 further characterized by said means for shorting said time delay menas including a resistor-capacitor circuit means being coupled in series with said unidirectional current flow circuit device for improving the speed of shorting said time delay means.
Claim 6
Dependent Claim
17 words
A circuit as in claim 1 further characterized by said means for shaping including a differentiator circuit.
Claim 7
Dependent Claim
17 words
A circuit as in claim 1 further characterized by said time delay means comprising a coaxial cable.
Claim 8
Dependent Claim
17 words
A circuit as in claim 1 further characterized by said time delay means comprising an RC network.
Claim 9
Independent Claim
145 words
A method of demodulating a frequency modulated signal embodying a frequency spectrum signal modulated on a carrier signal, said method comprising the steps of: a. shaping the modulated signal into a series of voltage transitions having a pulse repetition rate equal to that of the modulated signal; b. generating a square-wave signal in response to the voltage transitions, said generating step comprising, i. switching a multivibrator to a first state in response to said voltage transitions; ii. switching said multivibrator to a second state by means of a time delay means coupled between an output terminal of said multivibrator and an input terminal of said multivibrator; iii. shorting said time delay means after said multivibrator has been switched to the second state; and, c. integrating the square-wave output signal from said multivibrator so as to provide the frequency spectrum signal demodulated from the carrier signal.
Claim 10
Independent Claim
145 words
A method of demodulating a frequency modulated signal embodying a frequency spectrum signal modulated on a carrier signal, said method comprising the steps of: a. shaping the modulated signal into a series of voltage transitions having a pulse repetition rate equal to that of the modulated signal; b. generating a square-wave signal in response to the voltage transitions, said generating step comprising, i. switching a multivibrator to a first state in response to said voltage transitions; ii. switching said multivibrator to a second state by means of a time delay means coupled between an output terminal of said multivibrator and an input terminal of said multivibrator; iii. shorting said time delay means after said multivibrator has been switched to the second state; and, c. integrating the square-wave output signal from said multivibrator so as to provide the frequency spectrum signal demodulated from the carrier signal.
Claim 11
Dependent Claim
18 words
A method as in claim 8 further characterized by said step of shaping including differentiating the modulated signal.
Claim 12
Dependent Claim
33 words
A method as in claim 9 further characterized by said step of switching said multivibrator to a first state comprising coupling said differentiated modulated signal to a set input terminal of said multivibrator.
Claim 13
Dependent Claim
47 words
A method as in claim 8 further characterized by said step of switching said multivibrator to the second state comprising the step of delaying in time transitions at the output of said multivibrator and coupling the delayed multivibrator output to a reset input terminal of said multivibrator.
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) | 1981-05-22 | 1981-11-21 | 1982-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-22 | 1985-11-21 | 1986-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-22 | 1989-11-21 | 1990-05-23 | $7700.00 | Window Closed / Lapsed |