Technique for achieving the theoretical coding gain of digital signals incorporating error correction

Claim 2

A point-to-point communications system which transmits digital signals from a first location to only one second location via a communications medium having varying transmission characteristics, said system comprising a first adjustable equalizer at said first location for compensating for amplitude and phase distortion in said medium, a second adjustable equalizer at said second location for compensating for amplitude and phase distortion in said medium, means, responsive to digital signals received at said second location, for generating equalization coefficients for said second equalizer which are suitable for compensating for said amplitude and phase distortion, and for transmitting said generated equalization coefficients from said second location to said first equalizer a first Nyquist filter at said first location, a second Nyquist filter at said second location, and control means for assuring that only one of said first and second equalizers and only one of said first and second Nyquist filters is operative at any time.

Claim 3

The system of claim 1 wherein said transmitting means transmits said equalization coefficients to said first equalizer via said communications medium.

Claim 4

The system of claim 1 wherein said transmitting means transmits said equalization coefficients to said first equalizer via a second communications medium.

Claim 5

The system of claim 1 further including means for generating a training sequence and transmitting said training sequence from said first location to said second locations, and wherein the received digital signals to which said generating means is response is said training sequence.

Claim 6

The system of claim 4 further including means for recovering said training sequence at said second location and transmitting said training sequence from said second location to said first location, and means, responsive to said training sequence recovered at said first location, for generating equalization coefficients for a third adjustable equalizer at said first location which are suitable for compensating for said varying transmission characteristics, and transmitting these generated equalization coefficients from said first location to a fourth adjustable equalizer at said second location.

Claim 7

The apparatus of claim 1 further including an encoder incorporating error correction connected to said equalizer at said first location, and a decoder incorporating said error correction connected to said equalizer at said second location.

Claim 8

The system of claim 4 wherein said training sequence is transmitted at at least one predetermined time and said control means assures that said second equalizer is operative and said first equalizer is inoperative at each said predetermined time.

Claim 9

The system of claim 7 wherein said control means assures that said first equalizer is operative and said second equalizer is inoperative at times other than each said predetermined time.

Claim 10

The system of claim 8 further including a Nyquist filter at said first location, a Nyquist filter at said second location, and second control means for assuring that said Nyquist filter at said first location is operative and said Nyquist at said second location is inoperative at each said predetermined time and for assuring that said Nyquist filter at said second location is operative and said Nyquist filter at said first location is inoperative at times other than each said predetermined time.

Claim 11

The system of claim 1 wherein digital signals are also transmitted from said second location to said first location and said system further including means, responsive to digital signals received at said first location, for generating equalization coefficients for a third adjustable equalizer at said first location which are suitable for compensating for distortion in the received digital signals, and transmitting these generated equalization coefficients from said first location to a fourth adjustable equalizer at said second location.

Claim 12

The system of claim 10 wherein said transmitting means transmits said equalization coefficients to said fourth equalizer via said communications medium.

Claim 13

The system of claim 10 wherein said transmitting means transmits said equalization coefficients to said fourth equalizer via a second communications medium.

Claim 14

The system of claim 10 further including means for generating a second training sequence and transmitting said second training sequence from said second location to said first location, and wherein the received digital signals to which said third equalizer coefficient generating means is response to said second training sequence.

Claim 17

A multi-point communications system of the type wherein digital signals at a central location are transmitted to a plurality of remote locations via separate communications paths each having varying transmission characteristics, said system comprising an adjustable equalizer at one remote location for compensating for amplitude and phase distorting in an associated one of the communications paths, an adjustable equalizer at said central location for compensating for amplitude and phase distortion in said associated one of the communications paths, and means, responsive to digital signals received at said one remote location, for generating equalization coefficients for said adjustable equalizer at said one remote location which are suitable for compensating for said amplitude and phase distortion in said associated one of the communications paths, and transmitting these generated equalization coefficients from said one remote location to said equalizer at said central location.

Claim 18

A multi-point communications system of the type wherein digital signals at a central location are transmitted to a plurality of remote locations via separate communications paths each having varying transmission characteristics, said system comprising an adjustable equalizer at one remote location for compensating for amplitude and phase distorting in an associated one of the communications paths, an adjustable equalizer at said central location for compensating for amplitude and phase distortion in said associated one of the communications paths, and means, responsive to digital signals received at said one remote location, for generating equalization coefficients for said adjustable equalizer at said one remote location which are suitable for compensating for said amplitude and phase distortion in said associated one of the communications paths, and transmitting these generated equalization coefficients from said one remote location to said equalizer at said central location.

Claim 19

The system of claim 15 further including means for generating a training sequence and transmitting said sequence from said central location to said one remote location, and wherein the received digital signals to which said generating means is responsive is said training sequence.

Claim 20

The system of claim 15 further including control means for assuring that either said equalizer at said one remote location or said equalizer at said central location is operative upon the digital signal at any time.

Claim 21

The system and claim 17 wherein the received digital signals include a training sequence, said training sequence being transmitted at at least one predetermined time and said control means assures that said equalizer at said one remote location is operative and said equalizer at said central location is inoperative at each said predetermined time.

Claim 22

The system of claim 18 wherein said control means assures that said equalizer at said central location is operative and said equalizer at said one remote location is inoperative at times other than each said predetermined time.

Claim 23

The system of claim 19 further including a Nyquist filter at said one remote location, a Nyquist filter at said central location, and second control means for assuring that said Nyquist filter at said central location is operative and said Nyquist filter at said one remote location is inoperative at each predetermined time and for assuring that said Nyquist filter at said one remote location is operative and said Nyquist filter at said central location is inoperative at times other than each said predetermined time.

Claim 24

The system of claim 15 wherein digital signals are also transmitted from said one remote location to said central location and said system further including means, responsive to digital signals received at said central location, for generating equalization coefficients for a third adjustable equalizer at said central location which are suitable for compensating for distortion in the digital signals received at said central location, and transmitting these equalization coefficients from said central location to a fourth adjustable equalizer at said one remote location.

Claim 25

The system of claim 21 further including means for generating a second training sequence and transmitting second training sequence from said one remote location to said central location, and wherein the received digital signals to which said third equalizer coefficient generating means is responsive is said second training sequence.

Claim 26

The communications system of claim 21 wherein said equalization coefficients are transmitted to said one remote location via said communications medium.

Claim 27

The communications system of claim 21 wherein said equalization coefficients are transmitted to said one remote location via a second communications medium.

Claim 28

The system of claim 16 further including means for recovering said training sequence at said one remote location and transmitting said training sequence back to said central location, and means, responsive to said training sequence received at said central location, for generating equalization coefficients for a third adjustable equalizer at said central location which are suitable for distorting compensation, and transmitting said generated equalization coefficients from said central location to a fourth adjustable equalizer at said one remote location.

Claim 29

The system of claim 15 further including an encoder, incorporating error correction, connected to said equalizer at said central location, and a decoder, incorporating error correction, connected to said equalizer at said one remote location.

Claim 34

A point-to-point digital communications system which transmits digital signals from a first location to only one second location via a communications medium having varying transmission characteristics, said system comprising a first adjustable equalizer at said first location for compensating for amplitude and phase distortion in said medium, a second adjustable equalizer at said second location for compensating for amplitude and phase distortion in said medium, means, responsive to digital signals received at said first location, for generating equalization coefficients for said equalizer which are suitable for compensating for said amplitude and phase distortion, and for transmitting said generated equalization coefficients from said first location to said second location, said transmitted equalization coefficients being used at said second location for compensating for said amplitude and phase distortion in signal transmission from said second to said first location, and means, responsive to digital signals received at said second location, for generating equalization coefficients for said second equalizer which are suitable for compensating for said amplitude and phase distortion, and for transmitting said generated equalization coefficients from said second location to said first location, said transmitted equalization coefficients being used at said first location for compensating for said amplitude and phase distortion in signal transmission from said first to said second location.

Claim 35

A point-to-point digital communications system which transmits digital signals from a first location to only one second location via a communications medium having varying transmission characteristics, said system comprising a first adjustable equalizer at said first location for compensating for amplitude and phase distortion in said medium, a second adjustable equalizer at said second location for compensating for amplitude and phase distortion in said medium, means, responsive to digital signals received at said first location, for generating equalization coefficients for said equalizer which are suitable for compensating for said amplitude and phase distortion, and for transmitting said generated equalization coefficients from said first location to said second location, said transmitted equalization coefficients being used at said second location for compensating for said amplitude and phase distortion in signal transmission from said second to said first location, and means, responsive to digital signals received at said second location, for generating equalization coefficients for said second equalizer which are suitable for compensating for said amplitude and phase distortion, and for transmitting said generated equalization coefficients from said second location to said first location, said transmitted equalization coefficients being used at said first location for compensating for said amplitude and phase distortion in signal transmission from said first to said second location.