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US3614475A
Expired / Lapsed
US
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Phase shift circuit apparatus
Assignee: National Aeronautics and Space Administration
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Filing: 1970-07-21
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Granted: 1971-10-19
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Expires: 1990-07-21
Abstract
Abstract A phase shifting circuit for selectively shifting the phase of an input signal from 0* to 180*, the circuit maintaining the signal amplitude constant and independent of signal frequency. The circuit includes resistive and capacitive elements, a voltage variable impedance element, operational amplifier means and a phase detector coupled together in such a manner that a desired phase shift of anywhere between 0* and 180* can be selectively obtained in response to a simple adjustment of a circuit component.
Inventors
- 👤 Gordon J Deboo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:35
CPC Classifications
H; H03; H03H; H03H11/00; H03H11/02; H03H11/16; H03H11/20
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
160 words
Phase shifting apparatus comprising: input terminal means and output terminal means coupled together by a series circuit including first and second resistance means of equal value; operational amplifier means having one input thereof connected to said series circuit between said resistance means and another input thereof connected to said input terminal means through a capacitance means, the output of said amplifier means being connected to said output terminal means; phase detector means operatively coupled between said input terminal means and said output terminal means for providing an output signal responsive to the phase difference between signals appearing at said input terminal means and said output terminal means; and variable resistance means coupling said another input of said operational amplifier means to circuit ground, said resistance means being variable in response to the output of said phase detector means so as to maintain a predetermined phase shift between the signals appearing at said input terminal means and said output terminal means.
Claim 2
Dependent Claim
160 words
Phase shifting apparatus comprising: input terminal means and output terminal means coupled together by a series circuit including first and second resistance means of equal value; operational amplifier means having one input thereof connected to said series circuit between said resistance means and another input thereof connected to said input terminal means through a capacitance means, the output of said amplifier means being connected to said output terminal means; phase detector means operatively coupled between said input terminal means and said output terminal means for providing an output signal responsive to the phase difference between signals appearing at said input terminal means and said output terminal means; and variable resistance means coupling said another input of said operational amplifier means to circuit ground, said resistance means being variable in response to the output of said phase detector means so as to maintain a predetermined phase shift between the signals appearing at said input terminal means and said output terminal means.
Claim 3
Dependent Claim
18 words
Phase shift apparatus as set forth in claim 1 wherein said variable resistance means is a transistor means.
Claim 4
Dependent Claim
20 words
Phase shift apparatus as set forth in claim 2 wherein said variable resistance means is a field effect transistor means.
Claim 5
Dependent Claim
46 words
Phase shift apparatus as set forth in claim 3 and including circuit means for enabling the selective alteration of the relationship between the output of said phase detector means and the responsive variation of said resistance means, whereby said predetermined phase shift may be selectively chosen.
Claim 6
Dependent Claim
71 words
Phase shift apparatus as set forth in claim 4 wherein said circuit means includes a second operational amplifier means and a variable signal source means, said signal source means providing a signal of opposite polarity to that of said phase detector means and for addition thereto, said second operational amplifier means being responsive to the sum of the said signal addition to generate a voltage for application to said transistor means.
Claim 7
Dependent Claim
177 words
Phase shift circuit means comprising: input terminal means and output terminal means; operational amplifier means having one of its inputs coupled to said input terminal means through a first resistor means and to said output terminal means through a second resistor means, said second resistor means being of equal value to said first resistor means, a second input of said operational amplIfier means being coupled to said input terminal means by a capacitor means, the output of said operational amplifier means being coupled to said output terminal means; phase detector means coupled to said input terminal means and said output terminal means for generating a phase signal responsive to the difference in phase between signals appearing at said input terminal means and said output terminal means; and variable resistance means coupling said second input of said operational amplifier means to circuit ground, said variable resistance means being varied in response to said phase signal generated by said phase detector means so as to maintain a predetermined phase shift between said input terminal means and output terminal means.
Claim 8
Dependent Claim
177 words
Phase shift circuit means comprising: input terminal means and output terminal means; operational amplifier means having one of its inputs coupled to said input terminal means through a first resistor means and to said output terminal means through a second resistor means, said second resistor means being of equal value to said first resistor means, a second input of said operational amplIfier means being coupled to said input terminal means by a capacitor means, the output of said operational amplifier means being coupled to said output terminal means; phase detector means coupled to said input terminal means and said output terminal means for generating a phase signal responsive to the difference in phase between signals appearing at said input terminal means and said output terminal means; and variable resistance means coupling said second input of said operational amplifier means to circuit ground, said variable resistance means being varied in response to said phase signal generated by said phase detector means so as to maintain a predetermined phase shift between said input terminal means and output terminal means.
Claim 9
Dependent Claim
53 words
Phase shift circuit means as set forth in claim 6 and further including reference signal generating means for generating a reference signal for comparison with said phase signal generated by said phase detector means, said variable resistance means being varied in response to the difference between said reference signal and said phase signal.
Claim 10
Dependent Claim
55 words
Phase shift circuit means as set forth in claim 7 wherein said phase signal generated by said phase detector means is a voltage of one polarity, said reference signal is a voltage of the opposite polarity and said variable resistance means is a field effect transistor means operatively responsive to the difference between said voltages.
Claim 11
Dependent Claim
47 words
Phase shift circuit means as set forth in claim 8 wherein a second operational amplifier means responsive to the difference between said phase signal and said reference signal is used to provide a control voltage for application to the gate electrode of said field effect transistor means.
References Cited (Backward Citations)
US3436647A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-10-18 | 1975-04-19 | 1975-10-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-10-18 | 1979-04-19 | 1979-10-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-10-18 | 1983-04-19 | 1983-10-19 | $7700.00 | Window Closed / Lapsed |