US5111479A
Expired / Lapsed
US
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Spread spectrum receiver and carrier sense circuit therefor
Assignee: Faurecia Clarion Electronics Co Ltd
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Filing: 1990-10-26
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Granted: 1992-05-05
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Expires: 2010-10-26
Abstract
Abstract A carrier sense circuit for sensing a carrier component of a received signal in a spread spectrum system includes a multiplier which produces a squared signal by multiplying the received signal by itself, a filter which extracts from the squared signal a carrier component of a spread spectrum signal included in the squared signal, and a detecting circuit which detects the level of the carrier component and which outputs a carrier sense signal when the level of the carrier component is greater than a predetermined level. The filter is a band pass filter having a central frequecny of 2f c where f c is the central frequency of the spread spectrum signal. Where the spread spectrum system includes an initial synchronization circuit, and a correlation arrangement which correlates the received signal with a reference signal to produce correlation pulses, a circuit can be provided to start the initial synchronization circuit in response to simultaneous occurrence of the carrier sense signal and one of the correlation pulses.
Inventors
- 👤 Shigeo Akazawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:37
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/69; H04B1/707
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
94 words
A carrier sense circuit used in a spread spectrum receiver for sensing a carrier component of a received signal, comprising: operating means for outputting a squared signal which is a received signal multiplied by itself; a filter for extracting from said squared signal a carrier component of a spread spectrum signal included in said squared signal, said filter outputting said carrier component; and a detecting circuit for detecting the level of said carrier component and for outputting a carrier sense signal when the level of said carrier component is greater than a predetermined level.
Claim 2
Dependent Claim
94 words
A carrier sense circuit used in a spread spectrum receiver for sensing a carrier component of a received signal, comprising: operating means for outputting a squared signal which is a received signal multiplied by itself; a filter for extracting from said squared signal a carrier component of a spread spectrum signal included in said squared signal, said filter outputting said carrier component; and a detecting circuit for detecting the level of said carrier component and for outputting a carrier sense signal when the level of said carrier component is greater than a predetermined level.
Claim 3
Dependent Claim
35 words
A carrier sense circuit according to claim 1 wherein said filter is a band pass filter having a central frequency of 2f c , f c being the central frequency of said spread spectrum signal.
Claim 4
Dependent Claim
22 words
A carrier sense circuit according to claim 1 wherein said operating means includes a multiplier, which multiplies said received signal by itself.
Claim 5
Dependent Claim
109 words
A circuit for use in a spread spectrum receiver, said circuit comprising: operating means for outputting a squared signal which is a received signal multiplied by itself; a filter for extracting from said squared signal a carrier component of a spread spectrum signal included in said squared signal, said filter outputting said carrier component; a detecting circuit for detecting the level of said carrier component and for outputting a carrier sense signal when the level of said carrier component is greater than a predetermined level; and means for starting an initial synchronization circuit of a spread spectrum receiver in response to said carrier sense signal and a correlation pulse.
Claim 6
Dependent Claim
109 words
A circuit for use in a spread spectrum receiver, said circuit comprising: operating means for outputting a squared signal which is a received signal multiplied by itself; a filter for extracting from said squared signal a carrier component of a spread spectrum signal included in said squared signal, said filter outputting said carrier component; a detecting circuit for detecting the level of said carrier component and for outputting a carrier sense signal when the level of said carrier component is greater than a predetermined level; and means for starting an initial synchronization circuit of a spread spectrum receiver in response to said carrier sense signal and a correlation pulse.
Claim 7
Dependent Claim
33 words
A circuit according to claim 4 wherein said filter is a band pass filter having a central frequency of 2f c , f c being the central frequency of said spread spectrum signal.
Claim 8
Dependent Claim
22 words
A spread spectrum receiver according to claim 4 wherein said operating means includes a multiplier, which multiplies said received signal by itself.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-05-05 | 1995-11-04 | 1996-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-05-05 | 1999-11-04 | 2000-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-05-05 | 2003-11-04 | 2004-05-05 | $7700.00 | Window Closed / Lapsed |