US3701023A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phase jitter extraction method for data transmission systems
Assignee: International Business Machines Corp
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Filing: 1971-06-29
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Granted: 1972-10-24
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Expires: 1991-06-29
Abstract
Abstract A carrier recovery method and apparatus for generating a carrier having the proper frequency, relative phase and phase jitter to accurately demodulate a modulated signal having phase jitter. The phase jitter is detected with minimal distortion and modulated onto a carrier signal generated by means of phase locked oscillators.
Inventors
- 👤 Yang Fang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:47
CPC Classifications
H; H03; H03D; H03D1/00; H03D1/22; H03D1/24; H04; H04L; H04L27/00; H04L27/02; H04L27/06; H04L27/066
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
91 words
A method of generating a demodulation carrier signal for use in demodulating a modulated signal having phase jitter comprising the steps of: recovering a carrier signal having a frequency of said demodulation carrier signal; recovering a pilot signal from a received pilot signal having a frequency spaced away from the frequency band of said modulated signal; comparing said recovered pilot signal with said received pilot signal in a phase detector to detect said phase jitter; phase modulating said recovered carrier signal with said phase jitter to generate said demodulation carrier signal.
Claim 2
Independent Claim
91 words
A method of generating a demodulation carrier signal for use in demodulating a modulated signal having phase jitter comprising the steps of: recovering a carrier signal having a frequency of said demodulation carrier signal; recovering a pilot signal from a received pilot signal having a frequency spaced away from the frequency band of said modulated signal; comparing said recovered pilot signal with said received pilot signal in a phase detector to detect said phase jitter; phase modulating said recovered carrier signal with said phase jitter to generate said demodulation carrier signal.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein said third and fourth pilot signals are higher harmonics of said first and second pilot signals respectively.
Claim 4
Dependent Claim
22 words
The method of claim 1 wherein said third and fourth pilot signals are subharmonics of said first and second pilot signals respectively.
Claim 5
Dependent Claim
36 words
The method of claim 1 wherein said third pilot signal is a first order harmonic of said first pilot signal, and wherein said fourth pilot signal is a second order harmonic of said second pilot signal.
Claim 6
Independent Claim
250 words
A method of generating a demodulation carrier signal for use in demodulating a modulated signal having phase jitter comprising the steps of: receiving said modulated signal and at least a first and a second pilot signals; generating a third pilot signal, said third pilot signal having a frequency which is a harmonic of said first pilot signal and is synchronized with said firsT pilot signal; generating a fourth pilot signal, said fourth pilot signal having a frequency which is a harmonic of said second pilot signal and is synchronized with said second pilot signal, the order of said harmonic of said second pilot signal differing from the order of said harmonic of said first pilot signal by one; modulating said third pilot signal onto said fourth pilot signal thereby generating a modulation product; filtering said modulation product so as to retain only one sideband of said modulation product, said retained sideband having the frequency of said demodulation carrier signal; comparing, in a phase detector, one of said first and second pilot signals with a comparison harmonic of one of said third and fourth pilot signals respectively, said comparison harmonic having a frequency equal to said one of said first and second pilots signals, to generate an output signal including said phase jitter; filtering said output signal in a low pass filter to detect said phase jitter; phase modulating said retained sideband with said phase jitter thereby generating said demodulation carrier signal which jitters in phase synchronism with said modulated signal.
Claim 7
Independent Claim
250 words
A method of generating a demodulation carrier signal for use in demodulating a modulated signal having phase jitter comprising the steps of: receiving said modulated signal and at least a first and a second pilot signals; generating a third pilot signal, said third pilot signal having a frequency which is a harmonic of said first pilot signal and is synchronized with said firsT pilot signal; generating a fourth pilot signal, said fourth pilot signal having a frequency which is a harmonic of said second pilot signal and is synchronized with said second pilot signal, the order of said harmonic of said second pilot signal differing from the order of said harmonic of said first pilot signal by one; modulating said third pilot signal onto said fourth pilot signal thereby generating a modulation product; filtering said modulation product so as to retain only one sideband of said modulation product, said retained sideband having the frequency of said demodulation carrier signal; comparing, in a phase detector, one of said first and second pilot signals with a comparison harmonic of one of said third and fourth pilot signals respectively, said comparison harmonic having a frequency equal to said one of said first and second pilots signals, to generate an output signal including said phase jitter; filtering said output signal in a low pass filter to detect said phase jitter; phase modulating said retained sideband with said phase jitter thereby generating said demodulation carrier signal which jitters in phase synchronism with said modulated signal.
Claim 8
Dependent Claim
144 words
A demodulation carrier generation circuit for use in a modulated signal receiver comprising: carrier recovery circuit means for receiving a plurality of pilot signals and recovering therefrom a carrier signal having a frequency of said demodulation carrier signal; phase locked oscillator means for receiving a first pilot signal of said plurality of pilot signals and recovering therefrom a recovered pilot signal without phase jitter; phase detector means having a first input connected to said phase locked oscillator and having a second input for receiving said first pilot signal for comparing the phase of said recovered pilot signal with the phase of said first pilot signal to detect phase jitter of said first pilot signal; phase modulation means connected to said phase detector and to said carrier recovery circuit for modulating said recovered carrier signal with said detected phase jitter to generate said demodulation carrier.
Claim 9
Dependent Claim
144 words
A demodulation carrier generation circuit for use in a modulated signal receiver comprising: carrier recovery circuit means for receiving a plurality of pilot signals and recovering therefrom a carrier signal having a frequency of said demodulation carrier signal; phase locked oscillator means for receiving a first pilot signal of said plurality of pilot signals and recovering therefrom a recovered pilot signal without phase jitter; phase detector means having a first input connected to said phase locked oscillator and having a second input for receiving said first pilot signal for comparing the phase of said recovered pilot signal with the phase of said first pilot signal to detect phase jitter of said first pilot signal; phase modulation means connected to said phase detector and to said carrier recovery circuit for modulating said recovered carrier signal with said detected phase jitter to generate said demodulation carrier.
Claim 10
Dependent Claim
249 words
A demodulation carrier generating circuit for use in a modulated signal receiver comprising: first phase locked oscillator means having an input for receiving a plurality of received pilot signals having phase jitter and recovering therefrom a first recovered pilot signal having a frequency (n- 1) times the frequency of a first received pilot signal; second phase locked oscillator means having an input for receiving said plurality of received pilot signals and generating a signal therefrom having a frequency of n times the frequency of a second received pilot signal; modulation means connected to said first phase locked oscillator and to said second phase locked oscillator for generating a carrier signal having a frequency of said demodulation carrier; phase detector means having a first input for receiving said plurality of received pilot signals and having a second input for receiving the quadrature of the nth subharmonic of the output of said second phase locked oscillator, said phase detector providing at its output, a signal comprising said phase jitter; lowe-pass filter means connected to said output of said phase detector means, said low-pass filter means having a cut-off frequency characteristic significantly greater than the frequency of said phase jitter for passing the phase jitter component of said signal comprising said phase jitter; phase modulation means connected to said low-pass filter means and to said modulation means for modulating said generated carrier signal with said phase jitter component to provide a carrier signal which jitters in phase synchronism with said modulated signal.
Claim 11
Dependent Claim
249 words
A demodulation carrier generating circuit for use in a modulated signal receiver comprising: first phase locked oscillator means having an input for receiving a plurality of received pilot signals having phase jitter and recovering therefrom a first recovered pilot signal having a frequency (n- 1) times the frequency of a first received pilot signal; second phase locked oscillator means having an input for receiving said plurality of received pilot signals and generating a signal therefrom having a frequency of n times the frequency of a second received pilot signal; modulation means connected to said first phase locked oscillator and to said second phase locked oscillator for generating a carrier signal having a frequency of said demodulation carrier; phase detector means having a first input for receiving said plurality of received pilot signals and having a second input for receiving the quadrature of the nth subharmonic of the output of said second phase locked oscillator, said phase detector providing at its output, a signal comprising said phase jitter; lowe-pass filter means connected to said output of said phase detector means, said low-pass filter means having a cut-off frequency characteristic significantly greater than the frequency of said phase jitter for passing the phase jitter component of said signal comprising said phase jitter; phase modulation means connected to said low-pass filter means and to said modulation means for modulating said generated carrier signal with said phase jitter component to provide a carrier signal which jitters in phase synchronism with said modulated signal.
References Cited (Backward Citations)
US3577082A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |