Method and apparatus for fast determination of initial transversal equalizer coefficient values

Claim 2

In a synchronous data transmission system comprising a transmitter for transmitting data through a transmission channel causing distortions to a receiver including a transversal equalizer to compensate for the effects of said distortion, a method for determining the initial values of the equalizer coefficients comprising the steps of: selecting among the periodic binary pseudorandom sequences of length L, a sequence (u 1 ) of L binary elements u i having the following property: A.sub.0 =L and A.sub.j =-1 for j=1, . . . (L-1) where ##EQU27## adding to each element u i of the sequence (u i ) a constant m defined by the following relation: ##EQU28## whereby building a sequence (v i ) of L elements v i v i = u i + m; transmitting said sequence (v i ) through the transmission channel; receiving the sequence (x i ) of elements x i , each of the received elements x i corresponding to a transmitted element v i , and determining the initial values of the equalizer coefficients from the received sequence (x i ) and the transmitted sequence (v i ).

Claim 3

A method according to claim 1 wherein the step of determining the coefficient initial values includes the following steps: determining samples r j of the transmission channel impulse response obtained by correlating over a period L, the elements of received sequence (x i ) with the elements of emitted sequence (v i ), calculating autocorrelation matrix B of samples r j ; and determining the coefficient initial values from the following relation: C.sub.opt = B.sup.-1 R where C opt is the coefficient value column vector, B -1 is inversed matrix B, and R is the r j inversed column vector.

Claim 4

A method according to claim 2 wherein the determination of impulse response samples r j is obtained from the following relation: ##EQU29## where A 0 1 is the first coefficeint of the autocorrelation function of the transmitted sequence (v i ).

Claim 5

A method according to claim 3 wherein the determination of the coefficient initial values from the following relation: C.sub.opt = B.sup.-1 R is obtained by using the gradient method defined by: C.sup.(n) = C.sup.(n-1) - μ(B C.sup.(n-1) - R) where C.sup.(n-1) and C.sup.(n) respectively represent the coefficients column vectors at the (n-1) th and at the n th iteration, and μ is a constant.

Claim 6

A method according to claim 3 wherein A 0 1 = L.

Claim 7

In a synchronous data transmission system comprising a transmitter for transmitting data through a transmission channel causing distortions to a receiver including a transversal equalizer, a system for determining the initial values of the equalizer coefficeints comprising: in the transmitter means for generating a sequence (v i ) of L elements v i , each of the elements v i being defined by the relation v i = u i + m, where u i 's are the binary elements of a periodic binary pseudo-random sequence (u i ) having the following property A.sub.0 =L and A.sub.j =-1 for j=1, . . . , (L-1) ##EQU30## and m is a constant defined by the following relation ##EQU31## means for transmitting said sequence (v.sub.i) through the transmission channel, in the receiver means adapted for receiving the sequence (x i ) of elements x i , each of the received elements x i corresponding to a transmitted element v i , means for determining the samples r j of the transmission channel impulse response obtained by correlating over a period L the elements of received sequence (x i ) with the elements of emitted sequence (v i ); means for calculating autocorrelation matrix B of samples r j ; and means for determining the coefficient initial values from the following relation: C.sub.opt = B.sup.-1 R where C opt is the coefficient value column vector, B -1 is inversed matrix B, and R is the r j inversed column vector.

Claim 8

In a synchronous data transmission system comprising a transmitter for transmitting data through a transmission channel causing distortions to a receiver including a transversal equalizer, a system for determining the initial values of the equalizer coefficeints comprising: in the transmitter means for generating a sequence (v i ) of L elements v i , each of the elements v i being defined by the relation v i = u i + m, where u i 's are the binary elements of a periodic binary pseudo-random sequence (u i ) having the following property A.sub.0 =L and A.sub.j =-1 for j=1, . . . , (L-1) ##EQU30## and m is a constant defined by the following relation ##EQU31## means for transmitting said sequence (v.sub.i) through the transmission channel, in the receiver means adapted for receiving the sequence (x i ) of elements x i , each of the received elements x i corresponding to a transmitted element v i , means for determining the samples r j of the transmission channel impulse response obtained by correlating over a period L the elements of received sequence (x i ) with the elements of emitted sequence (v i ); means for calculating autocorrelation matrix B of samples r j ; and means for determining the coefficient initial values from the following relation: C.sub.opt = B.sup.-1 R where C opt is the coefficient value column vector, B -1 is inversed matrix B, and R is the r j inversed column vector.

Claim 9

A system according to claim 6 in which said means for determining the samples of the transmission channel impulse response implement the following relation: ##EQU32## where A 0 1 is the first coefficient of the autocorrelation function of the sequence (v 1 ).

Claim 10

A system according to claim 7 wherein A 0 1 = L.