US4890302A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit for extracting carrier signals
Assignee: US Philips Corp
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Filing: 1987-12-08
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Granted: 1989-12-26
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Expires: 2007-12-08
Abstract
Abstract In circuits for reproducing carriers for continuous phase modulation having a rational modulation index these signals are multiplied in a multiplier for producing a harmonic, with unique phases occurring due to phase addition irrespective of the information to be conveyed. This harmonic is selected by means of a bandpass filter and supplied to a divider for reproducing the carrier signal. However, as the desired phases only occur at certain instants the effect of jitter in the reproduced carrier signal is undesirably high. Jitter suppression is considerably improved by supplying to the bandpass filter only the instantaneous values of the virtually desired phases occurring at the specific instants.
Inventors
- 👤 Dirk Muilwijk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:20
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/227; H04L27/2275; H04L27/2276; H04L27/20; H04L27/2003; H04L27/2007; H04L27/2017
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
207 words
A receiver for a pulse-coded continuous phase-modulated carrier signal having a rational modulation index, comprising a coherent detector, and a circuit for providing an extracted carrier signal to said detector, said circuit comprising: a clock pulse regenerator; a multiplier, receiving said phase-modulated carrier signal, for generating an N th harmonic of said phase-modulated carrier signal, and producing a multiplier output comprising said N th harmonic, where N is an integer greater than 1; a first bandpass filter coupled to the multiplier and receiving said output for isolating said N th harmonic, and having a first filter output which is the isolated N th harmonic; and a divider connected to the first bandpass filter for receiving the isolated N th harmonic, having a dividend N and a divider output which is said extracted carrier signal, characterized by comprising a sampling circuit inserted between the multiplier and the first bandpass filter, connected to the clock pulse regenerator for instantaneous sampling of the N th harmonic under the control of a clock pulse signal originating from the clock pulse regenerator at no less than one predetermined sampling point per symbol time T of the data signal, and for conveying these instantaneously sampled signal values to the first bandpass filter only.
Claim 2
Dependent Claim
207 words
A receiver for a pulse-coded continuous phase-modulated carrier signal having a rational modulation index, comprising a coherent detector, and a circuit for providing an extracted carrier signal to said detector, said circuit comprising: a clock pulse regenerator; a multiplier, receiving said phase-modulated carrier signal, for generating an N th harmonic of said phase-modulated carrier signal, and producing a multiplier output comprising said N th harmonic, where N is an integer greater than 1; a first bandpass filter coupled to the multiplier and receiving said output for isolating said N th harmonic, and having a first filter output which is the isolated N th harmonic; and a divider connected to the first bandpass filter for receiving the isolated N th harmonic, having a dividend N and a divider output which is said extracted carrier signal, characterized by comprising a sampling circuit inserted between the multiplier and the first bandpass filter, connected to the clock pulse regenerator for instantaneous sampling of the N th harmonic under the control of a clock pulse signal originating from the clock pulse regenerator at no less than one predetermined sampling point per symbol time T of the data signal, and for conveying these instantaneously sampled signal values to the first bandpass filter only.
Claim 3
Dependent Claim
39 words
A receiver as claimed in claim 1, characterized by comprising a second bandpass filter inserted between the multiplier and the sampling arrangement, said second bandpass filter having a bandwidth exceeding by far the bandwidth of the first bandpass filter.
Claim 4
Dependent Claim
40 words
A receiver as claimed in claim 1, characterized in that the clock pulse regenerator comprises an adjustable delay means for being capable of reproducing a carrier wave for any type of continuous phase-modulated carrier signal having a rational modulation index.
Claim 5
Dependent Claim
37 words
A receiver as claimed in claim 3, comprising a third wideband pass filter receiving said phase-modulated carrier signal and having an output, said output being connected to an input to said multiplier and said clock pulse regenerator.
Claim 6
Dependent Claim
37 words
A receiver as claimed in claim 2, comprising a third wideband pass filter receiving said phase-modulated carrier signal and having an output, said output being connected to an input to said multiplier and said clock pulse regenerator.
Claim 7
Dependent Claim
206 words
A carrier reproducing circuit for extracting the carrier signal from a pulse-coded continuous phase-modulated carrier signal having a rational modulation index, comprising a clock pulse regenerator; a multiplier, receiving said phase-modulated carrier signal, having a multiplication factor N(N=2, 3, . . . ) for generating an N th harmonic of said phase-modulated carrier signal, and producing a multiplier output comprising said N th harmonic, where N is an integer greater than 1; a first bandpass filter coupled to the multiplier and receiving said output for isolating said N th harmonic, and having a first filter output which is the isolated N th harmonic; and a divider connected to the first bandpass filter for receiving the isolated N th harmonic, having a dividend N and a divider output which is said extracted carrier signal, characterized by comprising a sampling circuit inserted between the multiplier and the first bandpass filter, connected to the clock pulse regenerator for instantaneous sampling of the N th harmonic under the control of a clock pulse signal originating from the clock pulse regenerator at no less than one predetermined sampling point per symbol time T of the data signal, and for conveying these instantaneously sampled signal values to the first bandpass filter only.
Claim 8
Dependent Claim
206 words
A carrier reproducing circuit for extracting the carrier signal from a pulse-coded continuous phase-modulated carrier signal having a rational modulation index, comprising a clock pulse regenerator; a multiplier, receiving said phase-modulated carrier signal, having a multiplication factor N(N=2, 3, . . . ) for generating an N th harmonic of said phase-modulated carrier signal, and producing a multiplier output comprising said N th harmonic, where N is an integer greater than 1; a first bandpass filter coupled to the multiplier and receiving said output for isolating said N th harmonic, and having a first filter output which is the isolated N th harmonic; and a divider connected to the first bandpass filter for receiving the isolated N th harmonic, having a dividend N and a divider output which is said extracted carrier signal, characterized by comprising a sampling circuit inserted between the multiplier and the first bandpass filter, connected to the clock pulse regenerator for instantaneous sampling of the N th harmonic under the control of a clock pulse signal originating from the clock pulse regenerator at no less than one predetermined sampling point per symbol time T of the data signal, and for conveying these instantaneously sampled signal values to the first bandpass filter only.
Claim 9
Dependent Claim
39 words
A circuit as claimed in claim 6, characterized by comprising a second bandpass filter inserted between the multiplier and the sampling arrangement, said second bandpass filter having a bandwidth exceeding by far the bandwidth of the first bandpass filter.
Claim 10
Dependent Claim
40 words
A circuit as claimed in claim 6, characterized in that the clock pulse regenerator comprises an adjustable delay means for being capable of reproducing a carrier wave for any type of continuous phase-modulated carrier signal having a rational modulation index.
References Cited (Backward Citations)
US3835404A
Cited
US4339725A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-25 | 1993-06-26 | 1993-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-25 | 1997-06-26 | 1997-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-25 | 2001-06-26 | 2001-12-26 | $7700.00 | Window Closed / Lapsed |