US3793592A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase sensitive demodulator
Assignee: United States Department of the Navy
•
Filing: 1972-07-20
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Granted: 1974-02-19
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Expires: 1992-07-20
Abstract
Abstract A phase sensitive demodulator achieves signal isolation without the use of a transformer or other frequency sensitive component. A diode bridge which shunts the input signal is driven by the outputs of operational amplifiers. Signals which are not shunted are applied to the inputs of another operational amplifier.
Inventors
- 👤 L Matonak
- 👤 R Huber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:46
CPC Classifications
H; H03; H03D; H03D1/00; H03D1/22
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
181 words
A phase-sensitive demodulator comprising: a diode bridge having first, second, third, and fourth control junctions, said first and second control junctions being diametrically opposite each other and said third and fourth control junctions being diametrically opposite each other; means for receiving an input AC waveform and connecting it across said first and second control junctions of said diode bridge; an amplifier having a first input connected to said first control junction of said diode bridge, and a second input connected to said second control junction of said diode bridge, and an output which supplies a demodulated signal; a reference AC waveform generating means providing first and second outputs of opposite phase, but of identical frequency to each other and to said input AC waveform, a connection from said first output to said third control junction of said diode bridge, a coNnection from said second output to said fourth control junction of said diode bridge whereby said input AC waveform is gated either to said first or to said second input of said amplifier determined by said reference AC waveform generating means.
Claim 2
Dependent Claim
181 words
A phase-sensitive demodulator comprising: a diode bridge having first, second, third, and fourth control junctions, said first and second control junctions being diametrically opposite each other and said third and fourth control junctions being diametrically opposite each other; means for receiving an input AC waveform and connecting it across said first and second control junctions of said diode bridge; an amplifier having a first input connected to said first control junction of said diode bridge, and a second input connected to said second control junction of said diode bridge, and an output which supplies a demodulated signal; a reference AC waveform generating means providing first and second outputs of opposite phase, but of identical frequency to each other and to said input AC waveform, a connection from said first output to said third control junction of said diode bridge, a coNnection from said second output to said fourth control junction of said diode bridge whereby said input AC waveform is gated either to said first or to said second input of said amplifier determined by said reference AC waveform generating means.
Claim 3
Dependent Claim
47 words
The demodulator of claim 1 wherein said reference AC waveform generating means comprises: means for receiving a sinusoidal reference signal having an identical frequency to said input AC waveform and for providing a first squarewave to said first output and a second squarewave to said second output.
Claim 4
Dependent Claim
23 words
The demodulator of claim 2 wherein: said means for providing said first squarewave and said second squarewave comprises a pair of operational amplifiers.
Claim 5
Dependent Claim
85 words
The demodulator of claim 3 wherein said pair of operational amplifiers consists of: a second operational amplifier having an output; and said second operational amplifier having back-to-back zener diodes in a feedback path whereby said first squarewave appears at said output of said second operational amplifier; and a third operational amplifier having an output; and said third operational amplifier having an inverting input connected to said output of said second operational amplifier whereby said second squarewave appears at said output of said third operational amplifier.
Claim 6
Dependent Claim
20 words
The demodulator of claim 4 wherein: said AC input waveform and said AC reference waveform are 400 HZ in frequency.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-18 | 1977-08-20 | 1978-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-18 | 1981-08-20 | 1982-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-18 | 1985-08-20 | 1986-02-19 | $7700.00 | Window Closed / Lapsed |