US4525676A
Expired / Lapsed
US
⏱️ 0.0 years remaining
PSK Demodulation system having carrier frequency variation compensation
Assignee: NEC Corp
•
Filing: 1982-02-22
•
Granted: 1985-06-25
•
Expires: 2002-02-22
Abstract
Abstract A system for demodulation of phase shift keying signals with a bandpass filter tracked to input carrier frequency variation. This system provides means for detecting phase variations in the regenerated carrier wave from the demodulated signal, and means for controlling the phase of the regenerated carrier wave to compensate for the demodulation error owing to input carrier frequency variation.
Inventors
- 👤 Masaaki Atobe
- 👤 Yoshimi Tagashira
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:59
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/227; H04L27/2275; H04L27/2277
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
136 words
A system for demodulation of phase shift keying signals comprising: means, including a bandpass filter having an input and an output, which receives the phase shift keying signal for regenerating a carrier wave, said carrier wave passing through said bandpass filter; demodulator means having an input and output for demodulating the phase shift keying signal in response to the regenerated carrier wave which is input from said carrier wave regenerating means to thereby produce a demodulated signal; means for detecting phase variations in said regenerated carrier wave with respect to said demodulated signal; and phase control means responsive to the output of the phase variation detecting means to correct the phase of said carrier wave passing through said bandpass filter by controlling the phase of said carrier wave at the output of said band pass filter.
Claim 2
Independent Claim
136 words
A system for demodulation of phase shift keying signals comprising: means, including a bandpass filter having an input and an output, which receives the phase shift keying signal for regenerating a carrier wave, said carrier wave passing through said bandpass filter; demodulator means having an input and output for demodulating the phase shift keying signal in response to the regenerated carrier wave which is input from said carrier wave regenerating means to thereby produce a demodulated signal; means for detecting phase variations in said regenerated carrier wave with respect to said demodulated signal; and phase control means responsive to the output of the phase variation detecting means to correct the phase of said carrier wave passing through said bandpass filter by controlling the phase of said carrier wave at the output of said band pass filter.
Claim 3
Dependent Claim
26 words
A demodulation system according to claim 1 wherein said phase control means comprises a phase shifter responsive to the output of said phase variation detecting means.
Claim 4
Dependent Claim
42 words
A demodulation system according to claim 1 wherein said carrier wave regenerating means further comprises a remodulator connected to the output of said demodulator means and connected to the input of said bandpass filter and which receives the phase shift keying signal.
References Cited (Backward Citations)
JPS523543A
Cited
JPS523544A
Cited
US4308503A
Cited
US4361894A
Cited
US4409562A
Cited
US4339725A
Cited
JPS55149554A
Cited
JPS562770A
Cited
JPS5641010A
Cited
US4339823A
Cited
US4461014A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-06-24 | 1988-12-24 | 1989-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-06-24 | 1992-12-24 | 1993-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-06-24 | 1996-12-24 | 1997-06-25 | $7700.00 | Window Closed / Lapsed |