US5128626A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coherently demodulating arrangement including quasi-coherent demodulator for PSK signals
Assignee: NEC Corp
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Filing: 1991-05-28
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Granted: 1992-07-07
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Expires: 2011-05-28
Abstract
Abstract An arrangement for coherently demodulating PSK (phase-shift keying) signals, includes a quasi-coherent demodulator which implements coarse coherent demodulation on an incoming PSK-modulated IF signal using a variable frequency which is applied from a controllable local oscillator. The output of the quasi-coherent demodulator is applied to a coherent demodulator which also receives the output of a VCO (Voltage Controlled Oscillator). A phase detector receives the output of the coherent demodulator and applies the output thereof to the VCO via a loop filter. The output of the loop filter is applied to a local oscillator controller having an output which is used to control the controllable local oscillator.
Inventors
- 👤 Motoya Iwasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:40
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/085; H03L7/087; H03D; H03D1/00; H03D1/22; H03D1/2245; H03D1/2254; H03L7/093
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
154 words
An arrangement for coherently demodulating an incoming IF signal in a digital radio communications system, said arrangement comprising: a local oscillator, said local oscillator having a controllable output frequency; a quasi-coherent demodulator coupled to receive the incoming IF signal and the output of said local oscillator; a channel filter coupled to receive the output of said quasi-coherent demodulator; a coherent demodulator coupled to receive the output of said channel filter and a reproduced carrier, said coherent demodulator outputting a baseband signal; a phase detector coupled to said coherent demodulator for detecting a phase difference between said baseband signal and said reproduced carrier; a loop filter coupled to receive the output of said phase detector; a voltage controlled oscillator coupled to receive the output of said loop filter and to generate the reproduced carrier which is applied to said coherent demodulator; and a local oscillator controller coupled between said loop filter and said local oscillator.
Claim 2
Dependent Claim
154 words
An arrangement for coherently demodulating an incoming IF signal in a digital radio communications system, said arrangement comprising: a local oscillator, said local oscillator having a controllable output frequency; a quasi-coherent demodulator coupled to receive the incoming IF signal and the output of said local oscillator; a channel filter coupled to receive the output of said quasi-coherent demodulator; a coherent demodulator coupled to receive the output of said channel filter and a reproduced carrier, said coherent demodulator outputting a baseband signal; a phase detector coupled to said coherent demodulator for detecting a phase difference between said baseband signal and said reproduced carrier; a loop filter coupled to receive the output of said phase detector; a voltage controlled oscillator coupled to receive the output of said loop filter and to generate the reproduced carrier which is applied to said coherent demodulator; and a local oscillator controller coupled between said loop filter and said local oscillator.
Claim 3
Dependent Claim
29 words
An arrangement as claimed in claim 1, wherein the center frequency of the output of said local oscillator is equal to a nominal frequency of said incoming IF signal.
Claim 4
Dependent Claim
41 words
An arrangement as claimed in claim 1, wherein said local oscillator controller controls said local oscillator in a manner that the frequency difference between said incoming IF signal and the output signal of said local oscillator falls within a predetermined range.
Claim 5
Dependent Claim
41 words
An arrangement as claimed in claim 2, wherein said local oscillator controller controls said local oscillator in a manner that the frequency difference between said incoming IF signal and the output signal of said local oscillator falls within a predetermined range.
Claim 6
Dependent Claim
35 words
An arrangement as claimed in claim 1, further comprising, an analog-digital converter provided between said quasi-coherent demodulator and said channel filter; and a digital-to-analog converter provided between said local oscillator controller and said local oscillator.
References Cited (Backward Citations)
US3371281A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-07 | 1996-01-06 | 1996-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-07 | 2000-01-06 | 2000-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-07 | 2004-01-06 | 2004-07-07 | $7700.00 | Window Closed / Lapsed |