Wired spread spectrum data communication system
First Claim
1. A method for communication of a data signal over a low to medium frequency response and bandwidth transmission line having at times a line signal thereon substantially without interference to or by said line signal, said data signal and said line signal occupying substantially the same frequency band, said method comprising the steps of:
- (a) spread spectrum encoding a data signal by combining same with a pseudo-noise (PN) code signal;
(b) coupling said encoded data signal to said line for transmission thereon;
(c) adjusting the level of said encoded data signal to a selected level below the level of said line signal when present; and
(d) decoding said encoded data signal as adjusted by removing said PN code signal therefrom to provide said data signal.
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Accused Products
Abstract
A wired spread spectrum data communication system includes a modulator and a demodulator coupled to a transmission line having other signals thereon. The modulator includes a pseudo-noise (PN) generator and a clock providing, respectively, a PN code signal and a clock signal for combination in exclusive-OR (XOR) gates with a low bit rate data signal. The demodulator includes a phase locked loop for clock signal recovery and an identical PN generator providing, respectively, a local clock signal and PN code signal for combination in XOR gates with the encoded data signal for the removal of the clock and PN code signal components from the encoded data signal. The demodulator further includes circuitry for synchronizing the local PN code signal with the PN code component of the incoming encoded data signal.
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Citations
22 Claims
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1. A method for communication of a data signal over a low to medium frequency response and bandwidth transmission line having at times a line signal thereon substantially without interference to or by said line signal, said data signal and said line signal occupying substantially the same frequency band, said method comprising the steps of:
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(a) spread spectrum encoding a data signal by combining same with a pseudo-noise (PN) code signal; (b) coupling said encoded data signal to said line for transmission thereon; (c) adjusting the level of said encoded data signal to a selected level below the level of said line signal when present; and (d) decoding said encoded data signal as adjusted by removing said PN code signal therefrom to provide said data signal. - View Dependent Claims (2, 3)
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4. A method for communication of a data signal over a low to medium frequency response and bandwidth transmission line having at times a line signal thereon substantially without interference to or by said line signal, said data signal and said line signal occupying substantially the same frequency band, said method comprising the steps of:
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(a) spectrum spreading a data signal by combining same with a pseudo-noise (PN) code signal to provide a spectrum spread signal; (b) clocking said spectrum spread signal by combining same with a clock signal to provide an encoded data signal; (c) coupling said encoded data signal to said line for transmission thereon; (d) adjusting the level of said encoded data signal to a selected level below the level of said line signal when present; (e) receiving said encoded data signal as adjusted and having noise therewith including at times said line signal; (f) declocking said encoded data signal as adjusted by removing said clock signal therefrom to provide a declocked signal; (g) despreading said declocked signal by removing said PN code signal therefrom to provide a despread signal; and (h) removing said noise from said despread signal to provide said data signal. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. In combination:
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(a) a low to medium frequency response and bandwidth transmission line for communicating a line signal thereon; (b) modulator means coupled with said line, said modulator means receiving a data signal, providing on said line a spread spectrum encoded data signal in substantially the same frequency band as said line signal, and controlling the level of said encoded data signal, said data signal being so encoded and controlled in level as to substantially avoid interference with or by said line signal on said line; and (c) demodulator means coupled with said line remote from said modulator means, said demodulator means receiving and decoding said encoded data signal. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22)
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Specification