US3667067A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic circuit suitable for use as frequency selective amplifier or oscillator
Assignee: Individual
•
Filing: 1971-03-18
•
Granted: 1972-05-30
•
Expires: 1991-03-18
Abstract
Abstract An electronic circuit has two similar phase shift networks connected in cascade between a circuit input and the input of an amplifier providing a 180* phase-shift between its input and output. The output of the amplifier and first network are combined and the combination applied to the circuit output, providing an overall frequency response exhibiting a resonant frequency. The networks may be connected together via a buffer amplifier, and each comprises a resistance and a reactance interconnected to provide a phase lead or lag. The resonant frequency may be varied by varying the gain of the amplifier or the resistance or reactance of one or both networks. Variable gain feedback circuitry may be connected between the circuit output and input, so that the circuit is selectively operable as a frequency selective amplifier or oscillator in accordance with the gain of this circuitry.
Inventors
- 👤 Derek Alfred Levell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 18:48
CPC Classifications
H; H03; H03B; H03B5/00; H03B5/20; H03B5/24; H03F; H03F3/00; H03F3/189; H03F3/19; H03F3/191; H03B2201/00; H03B2201/01
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
131 words
An electronic circuit comprising: a first phase-shift network having an input constituting the circuit input and an output; a second phase-shift network having an input connected to the output of said first phase-shift network, whereby the first and second networks are connected in cascade, and an output; amplification circuitry having an input and an output and having its input connected to the output of said second phase-shift network and being adapted to deliver at its output an output signal in anti-phase with a corresponding input signal; summation circuitry having a first input connected to the output of said amplification circuitry, a second input connected to the output of said first phase-shift network and an output constituting the circuit output, whereby the circuit has an overall frequency response exhibiting a resonant frequency.
Claim 2
Dependent Claim
131 words
An electronic circuit comprising: a first phase-shift network having an input constituting the circuit input and an output; a second phase-shift network having an input connected to the output of said first phase-shift network, whereby the first and second networks are connected in cascade, and an output; amplification circuitry having an input and an output and having its input connected to the output of said second phase-shift network and being adapted to deliver at its output an output signal in anti-phase with a corresponding input signal; summation circuitry having a first input connected to the output of said amplification circuitry, a second input connected to the output of said first phase-shift network and an output constituting the circuit output, whereby the circuit has an overall frequency response exhibiting a resonant frequency.
Claim 3
Dependent Claim
46 words
A circuit as set forth in claim 1, including a buffer amplifier having an input connected to said output of said first phase-shift network and an output connected to said input of said second phase-shift network and also to said second input of said summation circuitry.
Claim 4
Dependent Claim
35 words
A circuit as set forth in claim 1, each said phase-shift network comprising a resistance and a reactance so interconnected as to provide a phase lead between said output and said input of said network.
Claim 5
Dependent Claim
35 words
A circuit as set forth in claim 1, each said phase-shift network comprising a resistance and a reactance so interconnected as to provide a phase lag between said output and said input of said network.
Claim 6
Dependent Claim
49 words
A circuit as set forth in claim 1, wherein said amplification circuitry comprises a variable gain amplifier, whereby the resonant frequency of the overall circuit frequency response is variable and errors in component values of said phase-shift network may be compensated, both by varying the gain of said amplifier.
Claim 7
Dependent Claim
38 words
A circuit as set forth in claim 5, said amplifier comprising a gain control arrangement adapted to vary the gain of said amplifier to produce a percentage change in said resonant frequency irrespective of the frequency value thereof.
Claim 8
Dependent Claim
39 words
A circuit as set forth in claim 3, wherein the resistance of at least one of said phase-shift networks is a variable resistance, whereby the resonant frequency of the overall circuit frequency response is variable by varying said resistance.
Claim 9
Dependent Claim
39 words
A circuit as set forth in claim 4, wherein the resistance of at least one of said phase-shift networks is a variable resistance, whereby the resonant frequency of the overall circuit frequency response is variable by varying said resistance.
Claim 10
Dependent Claim
39 words
A circuit as set forth in claim 3, wherein the reactance of at least one of said phase-shift networks is a variable reactance, whereby the resonant frequency of the overall circuit frequency response is variable by varying said reactance.
Claim 11
Dependent Claim
39 words
A circuit as set forth in claim 4, wherein the reactance of at least one of said phase-shift networks is a variable reactance, whereby the resonant frequency of the overall circuit frequency response is variable by varying said reactance.
Claim 12
Dependent Claim
71 words
A circuit as set forth in claim 1, further comprising a variable gain feedback circuit having an input connected to said output of said summation circuitry and an output connected to said input of said first phase-shift network, whereby the circuit is selectively operable as a frequency selective amplifier tuned to said resonant frequency or as an oscillator operating at said resonant frequency, according to the gain of said feedback circuit.
Claim 13
Dependent Claim
51 words
A circuit as set forth in claim 11, said amplification circuitry comprising a gain control arrangement connected to receive a gain-control signal significant of the magnitude of a physical quantity, whereby when the circuit is operated as an oscillator the frequency of oscillation may be varied in accordance with said magnitude.
References Cited (Backward Citations)
US2758211A
Cited
US2971165A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-30 | 1975-11-29 | 1976-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-30 | 1979-11-29 | 1980-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-30 | 1983-11-29 | 1984-05-30 | $7700.00 | Window Closed / Lapsed |