US3835404A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Extracting circuit for reproducing carrier signals from a multiphase modulated signal
Assignee: Fujitsu Ltd
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Filing: 1972-11-29
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Granted: 1974-09-10
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Expires: 1992-11-29
Abstract
Abstract A carrier reproducing circuit for demodulating a signal transmitted by a pulse coded modulation-multiphase modulation system in which the output of a carrier extracting circuit is sampled by a clock pulse of a bit repetitive frequency in a sampling circuit and the sampled output is applied to a band-pass filter having a pass band of a carrier frequency to reproduce a carrier of reduced phase jitter.
Inventors
- 👤 H Nakamura
- 👤 H Ohyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:36
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/227; H04L27/2275; H04L27/2276
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
165 words
In a system wherein a carrier having a known carrier frequency is modulated with information comprising bits occurring at a known bit repetitive frequency differing from the carrier frequency by a pulse-coded modulation-multiphase modulation transmitter to produce a signal for transmission, and having a receiver for the transmitted signal, wherein the transmitted signal as received is subject to jitter, a carrier reproducing circuit for use in the receiver for recovering and reproducing the carrier frequency of the received signal, substantially free of the effects of jitter, comprising: a. carrier extracting means to which the received signal is supplied, for extracting the carrier component therefrom; b. sampling means responsive to a clock signal of the said known bit repetitive frequency for sampling the extracted carrier component output of said carrier extracting means to provide a discontinuous output signal therefrom; and c. band-pass filter means for receiving and filtering the discontinuous output signal of said sampling means and having a bandpass substantially equal to the carrier frequency.
Claim 2
Dependent Claim
165 words
In a system wherein a carrier having a known carrier frequency is modulated with information comprising bits occurring at a known bit repetitive frequency differing from the carrier frequency by a pulse-coded modulation-multiphase modulation transmitter to produce a signal for transmission, and having a receiver for the transmitted signal, wherein the transmitted signal as received is subject to jitter, a carrier reproducing circuit for use in the receiver for recovering and reproducing the carrier frequency of the received signal, substantially free of the effects of jitter, comprising: a. carrier extracting means to which the received signal is supplied, for extracting the carrier component therefrom; b. sampling means responsive to a clock signal of the said known bit repetitive frequency for sampling the extracted carrier component output of said carrier extracting means to provide a discontinuous output signal therefrom; and c. band-pass filter means for receiving and filtering the discontinuous output signal of said sampling means and having a bandpass substantially equal to the carrier frequency.
Claim 3
Dependent Claim
58 words
A carrier reproducing circuit as claimed in claim 1, wherein, for a transmitted signal of n-phase modulation, said carrier extracting means comprises a multiplier for multiplying the received signal by n times, and a first band-pass filter for receiving the output of said multiplier and having a band pass of n times the frequency of the received signal.
Claim 4
Dependent Claim
50 words
A carrier reproducing circuit as claimed in claim 2, wherein said band-pass filter means comprises a second band-pass filter circuit for receiving and filtering the output of said sampling means and a frequency divider circuit for frequency dividing the output of said band-pass filter circuit by a factor of 1/n.
Claim 5
Dependent Claim
35 words
A carrier reproducing circuit as claimed in claim 1, wherein the clock pulse is applied to a waveform shaping circuit and a level converter circuit whose output, in turn, is applied to said sampling means.
Claim 6
Dependent Claim
32 words
A carrier reproducing circuit as claimed in claim 1, wherein said sampling means has a sampling width selected in accordance with thE condition of band width restriction imposed upon the input signal.
Claim 7
Dependent Claim
156 words
In a system wherein a carrier having a known carrier frequency is modulated, with information comprising bits occurring at a known bit repetitive frequency differing from the carrier frequency, by a pulse-coded modulation-multiphase modulation transmitter to produce a pulse code modulated-pulse shift keyed (PCM-PSK) signal for transmission, and having a receiver for the transmitted signal, wherein the transmitted signal as received is subject to jitter, a carrier reproducing circuit for use in the receiver for recovering and reproducing the carrier frequency of the received signal, substantially free of the effects of jitter, comprising: a. an extracting circuit responsive to the received PCM-PSK signal for extracting said carrier component from the received signal; b. a sampling circuit for sampling the output of said carrier extracting circuit with a clock pulse of the said bit repetitive frequency; and c. a band-pass filter supplied with the output of said sampling circuit for filtering the output of said sampling circuit.
Claim 8
Dependent Claim
156 words
In a system wherein a carrier having a known carrier frequency is modulated, with information comprising bits occurring at a known bit repetitive frequency differing from the carrier frequency, by a pulse-coded modulation-multiphase modulation transmitter to produce a pulse code modulated-pulse shift keyed (PCM-PSK) signal for transmission, and having a receiver for the transmitted signal, wherein the transmitted signal as received is subject to jitter, a carrier reproducing circuit for use in the receiver for recovering and reproducing the carrier frequency of the received signal, substantially free of the effects of jitter, comprising: a. an extracting circuit responsive to the received PCM-PSK signal for extracting said carrier component from the received signal; b. a sampling circuit for sampling the output of said carrier extracting circuit with a clock pulse of the said bit repetitive frequency; and c. a band-pass filter supplied with the output of said sampling circuit for filtering the output of said sampling circuit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-09 | 1978-03-11 | 1978-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-09 | 1982-03-11 | 1982-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-09 | 1986-03-11 | 1986-09-10 | $7700.00 | Window Closed / Lapsed |