US4143322A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carrier wave recovery system apparatus using synchronous detection
Assignee: NEC Corp
•
Filing: 1977-09-30
•
Granted: 1979-03-06
•
Expires: 1997-09-30
Abstract
Abstract A carrier wave recovery apparatus of the decision feedback type having analog multipliers of lower dynamic range. The modulated signal is phase detected by comparison with a VCO signal. The analog multipliers receive a signal derived by subtraction of the phase detected signal from the same phase detected signal compared with a reference. That signal is multiplied in an analog multiplier by the phase detected signal or by the signal produced from comparing the phase detected signal with a reference.
Inventors
- 👤 Tadao Shimamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:16
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/227; H04L27/2271; H04L27/2273; H04L27/0014; H04L2027/0044; H04L2027/0046; H04L2027/0048; H04L2027/0063; H04L2027/0067
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
211 words
A carrier wave recovery apparatus comprising: an input terminal for receiving a carrier-suppressed modulated signal; a voltage controlled oscillator forming a source of a carrier wave for demodulation of said modulated signal; first and second phase detector means supplied with the output of said voltage controlled oscillator directly and through a 90° phase shifter, respectively, for demodulating said modulated signal; first and second comparator means for determining the polarity of the output voltages of said first and second phase detector means with respect to a reference voltage and for providing a predetermined output voltage of a polarity depending on the determined polarity; a first subtractor for providing the difference between the outputs of said first phase detector and said first comparator; a second subtractor means for providing the difference between the output of said second phase detector and said second comparator; a first analog multiplier means for multiplying the outputs of said first subtractor and said second comparator; a second analog multiplier means for multiplying the outputs of said second subtractor and said first comparator; a third subtractor means for providing the difference between the outputs of said first and said second multipliers; and means for supplying the output of said third subtractor to said voltage controlled oscillator for phase control.
Claim 2
Dependent Claim
211 words
A carrier wave recovery apparatus comprising: an input terminal for receiving a carrier-suppressed modulated signal; a voltage controlled oscillator forming a source of a carrier wave for demodulation of said modulated signal; first and second phase detector means supplied with the output of said voltage controlled oscillator directly and through a 90° phase shifter, respectively, for demodulating said modulated signal; first and second comparator means for determining the polarity of the output voltages of said first and second phase detector means with respect to a reference voltage and for providing a predetermined output voltage of a polarity depending on the determined polarity; a first subtractor for providing the difference between the outputs of said first phase detector and said first comparator; a second subtractor means for providing the difference between the output of said second phase detector and said second comparator; a first analog multiplier means for multiplying the outputs of said first subtractor and said second comparator; a second analog multiplier means for multiplying the outputs of said second subtractor and said first comparator; a third subtractor means for providing the difference between the outputs of said first and said second multipliers; and means for supplying the output of said third subtractor to said voltage controlled oscillator for phase control.
Claim 3
Dependent Claim
39 words
A carrier wave recovery apparatus as claimed in claim 1 further comprising first and second low pass filter means interposed between said first phase detector and said first comparator, and between said second phase detector and said second comparator.
Claim 4
Dependent Claim
65 words
A carrier wave recovery apparatus as claimed in claim 1 further comprising first delay means, connected between said first phase detector and said first subtractor for imparting a delay corresponding to the delay caused by said first comparator, and second delay means, connected between said second phase detector and said second subtractor for imparting a delay corresponding to the delay caused by said second comparator.
Claim 5
Dependent Claim
41 words
A carrier wave recovery apparatus as claimed in claim 1 further comprising a first low pass filter connected between said first comparator and said first subtractor, and a second low pass filter connected between said second comparator and said second subtractor.
Claim 6
Dependent Claim
214 words
A carrier wave recovery apparatus comprising: an input terminal for receiving a carrier-suppressed modulated signal; a voltage controlled oscillator forming a source of a carrier wave for demodulation of said modulated signal; first and second phase detector means supplied with the output of said voltage controlled oscillator directly and through a 90° phase shifter, respectively, for demodulating said modulated signal; first and second comparator means for determining the polarity of the output voltages of said first and second phase detector means with respect to a reference voltage and for providing a predetermined output voltage of a polarity depending on the determined polarity; a first subtractor means for providing the difference between the outputs of said first phase detector and said first comparator; a second subtractor means for providing the difference between the output of said second phase detector and said second comparator; a first analog multiplier means for multiplying the outputs of said first subtractor and said second phase detector; a second analog multiplier means for multiplying the outputs of said second subtractor and said first phase detector; a third subtractor means for providing the difference between the outputs of said first and said second multipliers; and means for supplying the output of said third subtractor to said voltage controlled oscillator for phase control.
Claim 7
Dependent Claim
214 words
A carrier wave recovery apparatus comprising: an input terminal for receiving a carrier-suppressed modulated signal; a voltage controlled oscillator forming a source of a carrier wave for demodulation of said modulated signal; first and second phase detector means supplied with the output of said voltage controlled oscillator directly and through a 90° phase shifter, respectively, for demodulating said modulated signal; first and second comparator means for determining the polarity of the output voltages of said first and second phase detector means with respect to a reference voltage and for providing a predetermined output voltage of a polarity depending on the determined polarity; a first subtractor means for providing the difference between the outputs of said first phase detector and said first comparator; a second subtractor means for providing the difference between the output of said second phase detector and said second comparator; a first analog multiplier means for multiplying the outputs of said first subtractor and said second phase detector; a second analog multiplier means for multiplying the outputs of said second subtractor and said first phase detector; a third subtractor means for providing the difference between the outputs of said first and said second multipliers; and means for supplying the output of said third subtractor to said voltage controlled oscillator for phase control.
Claim 8
Dependent Claim
39 words
A carrier wave recovery apparatus as claimed in claim 5 further comprising first and second low pass filter means interposed between said first phase detector and said first comparator, and between said second phase detector and said second comparator.
Claim 9
Dependent Claim
65 words
A carrier wave recovery apparatus as claimed in claim 5 further comprising first delay means, connected between said first phase detector and said first subtractor for imparting a delay corresponding to the delay caused by said first comparator, and second delay means, connected between said second phase detector and said second subtractor for imparting a delay corresponding to the delay caused by said second comparator.
Claim 10
Dependent Claim
41 words
A carrier wave recovery apparatus as claimed in claim 5 further comprising a first low pass filter connected between said first comparator and said first subtractor, and a second low pass filter connected between said second comparator and said second subtractor.
References Cited (Backward Citations)
US4085378A
Cited
US4092606A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-05 | 1982-09-04 | 1983-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-05 | 1986-09-04 | 1987-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-05 | 1990-09-04 | 1991-03-06 | $7700.00 | Window Closed / Lapsed |