US4591797A
Expired / Lapsed
US
⏱️ 0.0 years remaining
PSK demodulator having an AFC circuit
Assignee: NEC Corp
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Filing: 1985-03-21
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Granted: 1986-05-27
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Expires: 2005-03-21
Abstract
Abstract A PSK demodulator is disclosed. The demodulator includes a voltage controlled oscillator response to a control circuit in a frequency converter for converting an input PSK signal as a function of the output of the voltage controlled oscillator. A carrier recovery circuit recovers a carrier wave from the output of the frequency converter means and applies the recovered output to a band-pass filter. A phase detector detects the output of the frequency converter as a function of the output of the band-pass filter and provides a demodulated signal and function thereof. A phase comparator is provided for detecting the phase difference between the input and output signals of the band-pass filter and a low-pass filter responsive to the output of the phase comparator provides the control signal.
Inventors
- 👤 Yoshio Tanimoto
- 👤 Masaaki Atobe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:21
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/227; H04L27/2275; H04L27/2276
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
126 words
A PSK demodulator comprising: voltage controlled oscillator means responsive to a control signal; frequency converter means for frequency converting an input PSK signal as a function of the output of said voltage controlled oscillator means; carrier recovery circuit means for recovering a carrier wave from the output of said frequency converter means; band-pass filter means receiving said recovered carrier wave; phase detector means for phase detecting the output of said frequency converter means as a function of the output of said band-pass filter means and providing a demodulated signal; phase comparator means for detecting the phase difference between the input and output signals of said band-pass filter means; and low-pass filter means responsive to the output of said phase comparator means for providing said control signal.
Claim 2
Dependent Claim
126 words
A PSK demodulator comprising: voltage controlled oscillator means responsive to a control signal; frequency converter means for frequency converting an input PSK signal as a function of the output of said voltage controlled oscillator means; carrier recovery circuit means for recovering a carrier wave from the output of said frequency converter means; band-pass filter means receiving said recovered carrier wave; phase detector means for phase detecting the output of said frequency converter means as a function of the output of said band-pass filter means and providing a demodulated signal; phase comparator means for detecting the phase difference between the input and output signals of said band-pass filter means; and low-pass filter means responsive to the output of said phase comparator means for providing said control signal.
Claim 3
Dependent Claim
57 words
A PSK demodulator as claimed in claim 1, wherein said carrier recovery circuit means comprises a frequency multiplier for frequency multiplying the output of said frequency converter means, a band-pass filter for band-limiting the output of said frequency multiplier, and a frequency divider for frequency dividing the output of said band-pass filter and providing said carrier wave.
Claim 4
Dependent Claim
42 words
A PSK demodulator as claimed in claim 1, wherein said carrier recovery circuit comprises a delay circuit for delaying the output of said frequency converter means, and a PSK modulator for modulating the output of said delay circuit with said demodulated signal.
References Cited (Backward Citations)
US4361894A
Cited
US4313219A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-05-26 | 1989-11-25 | 1990-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-05-26 | 1993-11-25 | 1994-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-05-26 | 1997-11-25 | 1998-05-27 | $7700.00 | Window Closed / Lapsed |