Multiplex communications – Wide area network – Packet switching
Patent
1984-03-23
1986-01-28
Olms, Douglas W.
Multiplex communications
Wide area network
Packet switching
375 1, H04J 1300
Patent
active
045675880
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 assigned code sequence shift. A receiver, synchronized to the clock, discriminates the signals transmitted by a predetermined transmitter from signals transmitted by the others by generating a first pseudo-random code that is a replica of the common bipolar pseudo-random code and has a code sequence shift corresponding to that of the predetermined transmitter, and a second bipolar pseudo-random code that is a replica of the common 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 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. The cross-correlation output of a primary correlation detector generates in-phase and quadrature-phase correlation signals, with the quadrature-phase signal being at a minimum when the receiver and predetermined transmitter are perfectly synchronized with each other. The ratio of the in-phase and quadrature-phase signals are processed to identify the presence of a data signal within a background of noise and to improve synchronization lock between the receiver and predetermined transmitter.
REFERENCES:
patent: 4281409 (1981-07-01), Schneider
patent: 4392220 (1983-07-01), Hirosaki et al.
patent: 4475215 (1984-10-01), Gutleber
Gaudier Dale
Olms Douglas W.
Sangamo Weston, Inc.
LandOfFree
Synchronization system for use in direct sequence spread spectru does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Synchronization system for use in direct sequence spread spectru, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Synchronization system for use in direct sequence spread spectru will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1310486