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US4601047A
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Code division multiplexer using direct sequence spread spectrum signal processing
Assignee: Atos Origin IT Services Inc
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Filing: 1984-03-23
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Granted: 1986-07-15
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Expires: 2004-03-23
Abstract
Abstract A plurality of transmitters synchronized to a common clock each transmit a data signal spread by a common bipolar pseudo-random code having a different predetermined assigned code sequence shift. A receiver, synchronized to the clock, discriminates the signal transmitted by a predetermined transmitter from signals transmitted by the others by generating a first bipolar pseudo-random code that is a replica of the common bipolar pseudo-radom code and has a code sequence shift corresponding to that of the predetermined transmitter, and a second bipolar pseudo-random code and has an unassigned code sequence shift. The difference between the first and second bipolar pseudo-random code sequences, which is a trinary code sequence, is cross-correlated with the incoming signals. The cross-correlation despreads only the signal applied by the sequence having the predetermined code sequence shift. Each receiver includes a number of correlation detectors offset from each other by a fraction of a code chip together with decision circuitry to identify cross-correlation peaks for optimum synchronization.
Inventors
- 👤 Lawrence B. Horwitz
- 👤 Eugene T. Wiggins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:43
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/69; H04B1/707; H04J; H04J13/00
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
172 words
A direct sequence spread spectrum code division multiplex system, comprising: a timing signal source; a plurality of transmitters synchronized to the timing signal source and each transmitting data spread by a bipolar pseudo-random code which is a different assigned shift of a common bipolar code sequence; and a receiver synchronized to said timing signal source for receiving said data signals and discriminating the signal transmitted by a predetermined transmitter spread by a bipolar pseudo-random code having a predetermined assigned code sequence shift from signals transmitted by the other transmitter, the receiver including means for generating a first bipolar pseudo-random code that is a replica of the transmitted common bipolar pseudo-random code and has the predetermined assigned code sequence shift, means for generating a second bipolar pseudo-random code that is a replica of the transmitted common bipolar pseudo-random code and has an unassigned code sequence shift, means for processing said first and second bipolar pseudo-random codes to obtain a trinary code sequence and means for cross-correlating said transmitted signals and said trinary sequence.
Claim 2
Dependent Claim
172 words
A direct sequence spread spectrum code division multiplex system, comprising: a timing signal source; a plurality of transmitters synchronized to the timing signal source and each transmitting data spread by a bipolar pseudo-random code which is a different assigned shift of a common bipolar code sequence; and a receiver synchronized to said timing signal source for receiving said data signals and discriminating the signal transmitted by a predetermined transmitter spread by a bipolar pseudo-random code having a predetermined assigned code sequence shift from signals transmitted by the other transmitter, the receiver including means for generating a first bipolar pseudo-random code that is a replica of the transmitted common bipolar pseudo-random code and has the predetermined assigned code sequence shift, means for generating a second bipolar pseudo-random code that is a replica of the transmitted common bipolar pseudo-random code and has an unassigned code sequence shift, means for processing said first and second bipolar pseudo-random codes to obtain a trinary code sequence and means for cross-correlating said transmitted signals and said trinary sequence.
Claim 3
Dependent Claim
16 words
The system of claim 1, wherein said bipolar code sequence is a maximal length (ML) sequence.
Claim 4
Dependent Claim
17 words
The system of claim 2, wherein said bipolar code sequence is a phase shift keyed (PSK) signal.
Claim 5
Dependent Claim
149 words
In a direct sequence spread spectrum code division multiplex system including a plurality of transmitters synchronized to a common timing signal and each transmitting a signal spread by a bipolar pseudo-random code which is a different assigned shift of a common bipolar code sequence: a receiver synchronized to said timing signal for receiving said transmitted signal spread by a bipolar pseudo-random code having a predetermined assigned code sequence shift, including means for generating a first bipolar pseudo-random code that is a replica of the transmitted common bipolar pseudo-random code and has the predetermined assigned code sequence shift, means for generating a second bipolar pseudo-random code that is a replica of the transmitted common bipolar pseudo-random code and has an unassigned code sequence shift, means for processing said first and second bipolar pseudo-random codes to obtain a trinary sequence and means for cross-correlating said transmitted signal and said trinary sequence.
Claim 6
Dependent Claim
149 words
In a direct sequence spread spectrum code division multiplex system including a plurality of transmitters synchronized to a common timing signal and each transmitting a signal spread by a bipolar pseudo-random code which is a different assigned shift of a common bipolar code sequence: a receiver synchronized to said timing signal for receiving said transmitted signal spread by a bipolar pseudo-random code having a predetermined assigned code sequence shift, including means for generating a first bipolar pseudo-random code that is a replica of the transmitted common bipolar pseudo-random code and has the predetermined assigned code sequence shift, means for generating a second bipolar pseudo-random code that is a replica of the transmitted common bipolar pseudo-random code and has an unassigned code sequence shift, means for processing said first and second bipolar pseudo-random codes to obtain a trinary sequence and means for cross-correlating said transmitted signal and said trinary sequence.
Claim 7
Dependent Claim
183 words
In a direct sequence spread spectrum code division multiplex system comprising: a timing signal source; a plurality of transmitters synchronized to the timing signal source and each transmitting a data signal spread by common bipolar pseudo-random code which is a different assigned shift of a common bipolar pseudo-random code sequence; and a receiver synchronized to the timing signal source for receiving said transmitted bipolar pseudo-random code having a predetermined assigned code sequence shift: a method of synchronizing the receiver to a predetermined one of said transmitters transmitting a data signal spread by the bipolar pseudo-random code having said predetermined assigned code sequence, comprising the steps of generating a first bipolar pseudo-random code that is a replica of the transmitted bipolar pseudo-random code having said predetermined assigned code sequence shift; generating a second bipolar pseudo-random code that is a replica of the transmitted bipolar pseudo-random code having an unassigned code sequence shift; processing said first and second bipolar pseudo-random codes to obtain a trinary sequence; cross-correlating said transmitted binary psueod-random codes and said trinary code sequence; and in response, generating a receiver timing signal.
Claim 8
Dependent Claim
183 words
In a direct sequence spread spectrum code division multiplex system comprising: a timing signal source; a plurality of transmitters synchronized to the timing signal source and each transmitting a data signal spread by common bipolar pseudo-random code which is a different assigned shift of a common bipolar pseudo-random code sequence; and a receiver synchronized to the timing signal source for receiving said transmitted bipolar pseudo-random code having a predetermined assigned code sequence shift: a method of synchronizing the receiver to a predetermined one of said transmitters transmitting a data signal spread by the bipolar pseudo-random code having said predetermined assigned code sequence, comprising the steps of generating a first bipolar pseudo-random code that is a replica of the transmitted bipolar pseudo-random code having said predetermined assigned code sequence shift; generating a second bipolar pseudo-random code that is a replica of the transmitted bipolar pseudo-random code having an unassigned code sequence shift; processing said first and second bipolar pseudo-random codes to obtain a trinary sequence; cross-correlating said transmitted binary psueod-random codes and said trinary code sequence; and in response, generating a receiver timing signal.
Claim 9
Dependent Claim
12 words
The method of claim 5, wherein said processing step includes a subtraction.
Claim 10
Dependent Claim
16 words
The method of claim 5, wherein said binary code sequence is a maximal length (ML) sequence.
Claim 11
Dependent Claim
17 words
The method of claim 5, wherein said binary code sequence is a phase shift keyed (PSK) signal.
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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) | 1989-07-14 | 1990-01-13 | 1990-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-14 | 1994-01-13 | 1994-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-14 | 1998-01-13 | 1998-07-15 | $7700.00 | Window Closed / Lapsed |