Adaptive differential PCM system with residual-driven adaptation of feedback predictor

Claim 2

An adaptive differential pulse code modulation system comprising: a transmitter including; a subtractor for deriving the difference E j between an input signal X j and a transmitter predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for regenerating the difference signal E j from said numeric representation N j ; summing means for summing the difference signal E j and the transmitter predicted value X j to provide a transmitter reconstructed signal X j ; predictor means having variable prediction coefficients for receiving the transmitter reconstructed signal X j from said summing means and generating therefrom a predictor output signal X jp comprising at least partially said transmitter predicted value X j ; a feedback loop for applying said transmitter predicted value X j to said summing means; a receiver comprising an inverse quantizer for regenerating the receiver quantized difference signal E j from the received numeric representation N j ; an adder for combining a receiver predicted value and a receiver quantized difference signal E j to provide a receiver reconstructed signal X j ; receiver predictor means having variable prediction coefficients, for receiving said receiver reconstructed signal and providing therefrom a receiver predictor output comprising at least partially said receiver predicted value; said predictor means in said transmitter and receiver, respectively, each being arranged to derive its predictor output signal X jp in accordance with the equation: ##EQU10## wherein A 1 -A n are the predictor coefficient values in said transmitter and receiver defined by: ##EQU11## where i=the number of the particular predictor coefficient, =1 . . . n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E j is the value of the quantized difference signal at time point j; A i j is the respective predictor coefficient at time point j; F i is a non-linear function; X j is the sum of the difference signal E j and the predicted value X j .

Claim 3

An adaptive differential pulse code modulation system comprising: a transmitter including; a subtractor for deriving the difference E j between an input signal X j and a transmitter predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for regenerating the difference signal E j from said numeric representation N j ; summing means for summing the difference signal E j and the predicted value X j to provide a transmitter reconstructed signal X j ; predictor means having variable prediction coefficients for receiving the reconstructed signal X j from said summing means and generating therefrom a transmitter predictor output signal X jp comprising at least partially said predicted value X j ; a feedback loop for applying said transmitter predicted value X j to said summing means; a receiver comprising an inverse quantizer for regenerating the receiver quantized difference signal E j from the received numeric representation N j ; an adder for combining a receiver predicted value and a receiver quantized difference signal E j to provide a receiver reconstructed signal X j ; receiver predictor means having variable prediction coefficients, for receiving said receiver reconstructed signal and providing therefrom a receiver predictor output comprising at least partially said receiver predicted value; said predictor means in said transmitter and receiver, respectively, each being arranged to derive each prediction coefficient using an equation consisting essentially of a decay term and a non-linear function having at least one set of arguments comprising a finite number of past values of said difference signal E j and having no arguments comprising the value of said reconstructed signal X j .

Claim 4

An adaptive differential pulse code modulation system comprising: a transmitter including; a subtractor for deriving the difference E j between an input signal X j and a transmitter predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for regenerating the difference signal E j from said numeric representation N j ; summing means for summing the difference signal E j and the predicted value X j to provide a transmitter reconstructed signal X j ; predictor means having variable prediction coefficients for receiving the reconstructed signal X j from said summing means and generating therefrom a transmitter predictor output signal X jp comprising at least partially said predicted value X j ; a feedback loop for applying said transmitter predicted value X j to said summing means; a receiver comprising an inverse quantizer for regenerating the receiver quantized difference signal E j from the received numeric representation N j ; an adder for combining a receiver predicted value and a receiver quantized difference signal E j to provide a receiver reconstructed signal X j ; receiver predictor means having variable prediction coefficients, for receiving said receiver reconstructed signal and providing therefrom a receiver predictor output comprising at least partially said receiver predicted value; said predictor means in said transmitter and receiver, respectively, each being arranged to derive each prediction coefficient using an equation consisting essentially of a decay term and a non-linear function having at least one set of arguments comprising a finite number of past values of said difference signal E j and having no arguments comprising the value of said reconstructed signal X j .

Claim 5

A system as defined in claim 1 or 2, wherein said predictors each have two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU12## where j is a particular sample period; δ 1 and δ 2 are positive values much smaller than 1; g 1 and g 2 and d are proper positive constants.

Claim 6

An adaptive differential pulse code modulation system as defined in claim 3, wherein each first said predictor means provides a part only of the predicted value and said transmitter and said receiver each further comprise: second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ) and a second adder for summing the output of the first-mentioned predictor means and the partial predicted value to provide said predicted value.

Claim 7

A system as defined in claim 3, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:8 and 1:4, respectively.

Claim 8

A system as defined in claim 5, wherein the constants g 1 and g 2 are substantially equal.

Claim 9

A system as defined in claim 6, wherein the constants δ 1 , δ 2 , g 1 and g 2 are substantially equal to 1/256, 1/128, 1/32 and 1/32, respectively.

Claim 10

A system as defined in claim 1 or 2, wherein said predictors each have two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU13##

Claim 11

An adaptive differential pulse code modulation system as defined in claim 8, wherein each first said predictor means provides a part only of the predicted value and said transmitter and said receiver each further comprise: second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ) and a second adder for summing the output of the first-mentioned predictor means and the partial predicted value to provide said predicted value.

Claim 12

A system as defined in claim 8, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:2√2 and unity, respectively.

Claim 13

A system as defined in claim 10, wherein the constants δ 1 , δ 2 , g 1 and g 2 are about 1/181, 1/90, 1/64 and 1/90, respectively.

Claim 14

An adaptive differential pulse code modulation system as defined in claim 1, wherein each first said predictor means provides a part only of the predicted value and said transmitter and said receiver each further comprise: second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ) and a second adder for summing the output of the first-mentioned predictor means and the partial predicted value to provide said predicted value.

Claim 15

An adaptive differential pulse code modulation system comprising: a transmitter including; a subtractor for deriving the difference E j between an input signal X j and a transmitter predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for regenerating the difference signal E j from said numeric representation N j ; first summing means for summing the difference signal E j and the transmitter predicted value X j to provide a transmitter reconstructed signal X j ; first predictor means having variable prediction coefficients for receiving the output X j of said summing means and generating therefrom a transmitter predictor output signal X jp comprising a part of said predicted value X j ; a feedback loop for applying said transmitter predicted value X j to said first summing means; a receiver including an inverse quantizer for recovering a receiver quantized difference signal (E j ) from a received numeric representation (N j ); first receiver summing means for combining a receiver predicted value and a receiver quantized difference signal (E j ) to provide a receiver reconstructed signal (X j ); first receiver predictor means having variable prediction coefficients, for receiving said receiver reconstructed signal and providing therefrom a receiver predictor output signal (X jp ) comprising a part of said receiver predicted value (X j ); a feedback loop for applying said receiver predicted value (X j ) to said first receiver summing means; the transmitter and the receiver each comprising: second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ); a second summing means for summing the respective outputs X jp and X jo of the first-mentioned predictor means and said second predictor means to provide said predicted value X j ; a third summing means for deriving the sum E' j of the quantized difference signal E j and the partial predictor output X jo of the second predictor means; each said first predictor being arranged to derive its predictor output X jp in accordance with the equation: ##EQU14## wherein A 1 -A n are the predictor coefficient values in said transmitter and receiver defined by: ##EQU15## where i=the number of the particular predictor coefficient; =- n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E' j is the sum of the quantized difference signal E j at time j and the output X jo of said second predictor means; A i j is the respective predictor coefficient at time point j; F i is a non-linear function; X j is the sum of the difference signal E j and the predicted value X j .

Claim 16

An adaptive differential pulse code modulation system comprising: a transmitter including; a subtractor for deriving the difference E j between an input signal X j and a transmitter predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for regenerating the difference signal E j from said numeric representation N j ; first summing means for summing the difference signal E j and the transmitter predicted value X j to provide a transmitter reconstructed signal X j ; first predictor means having variable prediction coefficients for receiving the output X j of said summing means and generating therefrom a transmitter predictor output signal X jp comprising a part of said predicted value X j ; a feedback loop for applying said transmitter predicted value X j to said first summing means; a receiver including an inverse quantizer for recovering a receiver quantized difference signal (E j ) from a received numeric representation (N j ); first receiver summing means for combining a receiver predicted value and a receiver quantized difference signal (E j ) to provide a receiver reconstructed signal (X j ); first receiver predictor means having variable prediction coefficients, for receiving said receiver reconstructed signal and providing therefrom a receiver predictor output signal (X jp ) comprising a part of said receiver predicted value (X j ); a feedback loop for applying said receiver predicted value (X j ) to said first receiver summing means; the transmitter and the receiver each comprising: second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ); a second summing means for summing the respective outputs X jp and X jo of the first-mentioned predictor means and said second predictor means to provide said predicted value X j ; a third summing means for deriving the sum E' j of the quantized difference signal E j and the partial predictor output X jo of the second predictor means; each said first predictor being arranged to derive its predictor output X jp in accordance with the equation: ##EQU14## wherein A 1 -A n are the predictor coefficient values in said transmitter and receiver defined by: ##EQU15## where i=the number of the particular predictor coefficient; =- n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E' j is the sum of the quantized difference signal E j at time j and the output X jo of said second predictor means; A i j is the respective predictor coefficient at time point j; F i is a non-linear function; X j is the sum of the difference signal E j and the predicted value X j .

Claim 17

A system as defined in claim 13, wherein said first predictors each have two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU16## where j is a particular sample period; δ 1 and δ 2 are positive values much smaller than 1; g 1 and g 2 and d are proper positive constants.

Claim 18

A system as defined in claim 14, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:8 and 1:4, respectively.

Claim 19

A system as defined in claim 15, wherein the constants g 1 and g 2 are substantially equal.

Claim 20

A system as defined in claim 16, wherein the constants δ 1 , δ 2 , g 1 and g 2 are substantially equal to 1/256, 1/128, 1/32 and 1/32, respectively.

Claim 21

A system as defined in claim 13, wherein said first predictors each have two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU17##

Claim 22

A system as defined in claim 18, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:2√2 and unity, respectively.

Claim 23

A system as defined in claim 19, wherein the constants δ 1 , δ 2 , g 1 and g 2 are about 1/181, 1/90, 1/64 and 1/90, respectively.

Claim 24

A transmitter for an adaptive differential pulse code modulation system including; a subtractor for deriving the difference E j between an input signal X j and a predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for recovering the difference signal E j from said numeric representation N j ; summing means for summing the difference signal E j and the predicted value X j to provide a reconstructed signal X j ; predictor means having variable prediction coefficients for receiving the output X j of said summing means and generating therefrom a predictor output signal X jp comprising at least partially said predicted value X j ; and a feedback loop for applying said predicted value to said summing means; said predictor means being arranged to derive its predictor value X jp in accordance with the equation: ##EQU18## wherein A i -A n are the predictor coefficient values defined by: ##EQU19## where i=the number of the particular predictor coefficient

Claim 25

A transmitter for an adaptive differential pulse code modulation system including; a subtractor for deriving the difference E j between an input signal X j and a predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for recovering the difference signal E j from said numeric representation N j ; summing means for summing the difference signal E j and the predicted value X j to provide a reconstructed signal X j ; predictor means having variable prediction coefficients for receiving the output X j of said summing means and generating therefrom a predictor output signal X jp comprising at least partially said predicted value X j ; and a feedback loop for applying said predicted value to said summing means; said predictor means being arranged to derive its predictor value X jp in accordance with the equation: ##EQU18## wherein A i -A n are the predictor coefficient values defined by: ##EQU19## where i=the number of the particular predictor coefficient

Claim 26

=1. . . n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E j is the value of the quantized difference signal at time point j; A i j is the respective predictor coefficient at time point j; F i is a non-linear function X j is the sum of the difference signal E j and the predicted value X j .

Claim 27

=1. . . n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E j is the value of the quantized difference signal at time point j; A i j is the respective predictor coefficient at time point j; F i is a non-linear function X j is the sum of the difference signal E j and the predicted value X j .

Claim 28

A transmitter for an adaptive differential pulse code modulation system including; a subtractor for deriving the difference E j between an input signal X j and a predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for recovering the difference signal E j from said numeric representation N j ; summing means for summing the difference signal E j and the predicted value X j to provide a reconstructed signal X j ; predictor means having variable prediction coefficients for receiving the reconstructed signal X j from said summing means and generating therefrom a predictor output signal X jp comprising at least partially said predicted value X j ; and a feedback loop for applying said predicted value to said summing means; said predictor means being arranged to derived each prediction coefficient using an equation consisting essentially of a decay term and a non-linear function having at least one set of arguments comprising a finite number of past values of said difference signal E j and having no arguments comprising the value of said reconstructed signal X j .

Claim 29

A transmitter for an adaptive differential pulse code modulation system including; a subtractor for deriving the difference E j between an input signal X j and a predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for recovering the difference signal E j from said numeric representation N j ; summing means for summing the difference signal E j and the predicted value X j to provide a reconstructed signal X j ; predictor means having variable prediction coefficients for receiving the reconstructed signal X j from said summing means and generating therefrom a predictor output signal X jp comprising at least partially said predicted value X j ; and a feedback loop for applying said predicted value to said summing means; said predictor means being arranged to derived each prediction coefficient using an equation consisting essentially of a decay term and a non-linear function having at least one set of arguments comprising a finite number of past values of said difference signal E j and having no arguments comprising the value of said reconstructed signal X j .

Claim 30

A transmitter as defined in claim 21 or 22 wherein said predictor means has two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU20## where j is a particular sample period; δ 1 and δ 2 are positive values much smaller than 1; g 1 and g 2 and d are proper positive constants.

Claim 31

A transmitter as defined in claim 23, wherein the first said predictor means provides a part only of the predicted value and said transmitter further comprises: second prediction means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ) and a second adder for summing the output of the first-mentioned predictor means and the partial predicted value to provide said predicted value.

Claim 32

A transmitter as defined in claim 23, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:8 and 1:4, respectively.

Claim 33

A transmitter as defined in claim 25, wherein the constants g 1 and g 2 are substantially equal.

Claim 34

A transmitter as defined in claim 26, wherein the constants δ 1 , δ 2 , g 1 and g 2 are substantially equal to 1/256, 1/128, 1/32 and 1/32, respectively.

Claim 35

A transmitter as defined in claim 21 or 22, wherein said predictors each have two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU21##

Claim 36

A transmitter as defined in claim 28, wherein the first said predictor means provides a part only of the predicted value and said transmitter further comprises: second prediction means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ) and a second adder for summing the output of the first-mentioned predictor means and the partial predicted value to provide said predicted value.

Claim 37

A transmitter as defined in claim 28, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:2√2 and unity, respectively.

Claim 38

A transmitter as defined in claim 30, wherein the constants δ 1 , δ 2 , g 1 and g 2 are about 1/181, 1/90, 1/64 and 1/90, respectively.

Claim 39

A transmitter as defined in claim 21, wherein the first said predictor means provides a part only of the predicted value and said transmitter further comprises: second prediction means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ) and a second adder for summing the output of the first-mentioned predictor means and the partial predicted value to provide said predicted value.

Claim 40

A transmitter for an adaptive differential pulse code modulation system including; a subtractor for deriving the difference E j between an input signal X j and a predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for recovering the difference signal E j from said numeric representation N j ; summing means for summing the difference signal E j and the predicted value X j ; first predictor means having variable prediction coefficients for receiving the reconstructed signal X j from said summing means and generating therefrom a predictor output signal X jp comprising a part of said predicted value X j ; and a feedback loop for applying said predicted value X j to said first summing means; second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ); a second summing means for summing the respective outputs (X jp and X jo ) of the first predictor means and the second predictor means to provide said predicted value X j ; third summing means for deriving the sum E' j of the quantized difference signal E j and the partial predicted value (X jo ) from said second predictor means; said first predictor means being arranged to derive its predictor value X jp in accordance with the equation: ##EQU22## wherein A i -A n are the predictor coefficient values defined by: ##EQU23## where i=the number of the particular predictor coefficient

Claim 41

A transmitter for an adaptive differential pulse code modulation system including; a subtractor for deriving the difference E j between an input signal X j and a predicted value X j , a quantizer for quantizing the difference signal E j from said subtractor to obtain a numeric representation N j thereof; an inverse quantizer for recovering the difference signal E j from said numeric representation N j ; summing means for summing the difference signal E j and the predicted value X j ; first predictor means having variable prediction coefficients for receiving the reconstructed signal X j from said summing means and generating therefrom a predictor output signal X jp comprising a part of said predicted value X j ; and a feedback loop for applying said predicted value X j to said first summing means; second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ); a second summing means for summing the respective outputs (X jp and X jo ) of the first predictor means and the second predictor means to provide said predicted value X j ; third summing means for deriving the sum E' j of the quantized difference signal E j and the partial predicted value (X jo ) from said second predictor means; said first predictor means being arranged to derive its predictor value X jp in accordance with the equation: ##EQU22## wherein A i -A n are the predictor coefficient values defined by: ##EQU23## where i=the number of the particular predictor coefficient

Claim 42

=1. . . n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E' j is the sum of the quantized difference signal E j at time j and the output X jo of said second predictor means; A i j is the respective predictor coefficient at time point j; F i is a non-linear function; X j is the sum of the difference signal E j and the predicted value X j .

Claim 43

=1. . . n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E' j is the sum of the quantized difference signal E j at time j and the output X jo of said second predictor means; A i j is the respective predictor coefficient at time point j; F i is a non-linear function; X j is the sum of the difference signal E j and the predicted value X j .

Claim 44

A transmitter as defined in claim 33, including predictors each having two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU24## where j is a particular sample period; δ 1 and δ 2 are positive values much smaller than 1; g 1 and g 2 and d are proper positive constants.

Claim 45

A transmitter as defined in claim 34, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:8 and 1:4, respectively.

Claim 46

A transmitter as defined in claim 35, wherein the constants g 1 and g 2 are substantially equal.

Claim 47

A transmitter as defined in claim 36, wherein the constants δ 1 , δ 2 , g 1 and g 2 are substantially equal to 1/256, 1/128, 1/32 and 1/32, respectively.

Claim 48

A transmitter as defined in claim 33, including predictors each having two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU25##

Claim 49

A transmitter as defined in claim 38, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:2√2 and unity, respectively.

Claim 50

A tramsmitter as defined in claim 39, wherein the constants δ 1 , δ 2 , g 1 and g 2 are about 1/181, 1/90, 1/64 and 1/90, respectively.

Claim 51

A receiver for an adaptive differential pulse code modulation system comprising an inverse quantizer for recovering a receiver quantized difference signal E j from a received numeric representation N j ; an adder for combining a receiver predicted value X j and a receiver quantized difference signal E j to provide a reconstructed signal X j ; receiver predictor means having variable prediction coefficients, for receiving said reconstructed signal and providing therefrom a predictor output comprising at least partially said receiver predicted value; said predictor means being arranged to derive its predictor output X jp in accordance with the equation: ##EQU26## wherein A i -A n are the predictor coefficient values defined by: ##EQU27## where i=the number of the predictor coefficient =- n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E j is the value of the quantized difference signal at time point j; A i j is the respective predictor coefficient at time point j; F i is a non-linear function; X j is the sum of the difference signal E j and the predicted value X j .

Claim 52

A receiver for an adaptive differential pulse code modulation system comprising an inverse quantizer for recovering a receiver quantized difference signal E j from a received numeric representation N j ; an adder for combining a receiver predicted value X j and a receiver quantized difference signal E j to provide a reconstructed signal X j ; receiver predictor means having variable prediction coefficients, for receiving said reconstructed signal and providing therefrom a predictor output comprising at least partially said receiver predicted value; said predictor means being arranged to derive its predictor output X jp in accordance with the equation: ##EQU26## wherein A i -A n are the predictor coefficient values defined by: ##EQU27## where i=the number of the predictor coefficient =- n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E j is the value of the quantized difference signal at time point j; A i j is the respective predictor coefficient at time point j; F i is a non-linear function; X j is the sum of the difference signal E j and the predicted value X j .

Claim 53

A receiver for an adaptive differential pulse code modulation system comprising an inverse quantizer for recovering a receiver quantized difference signal E j from a received numeric representation N j ; an adder for combining a receiver predicted value X j and a receiver quantized difference signal E j to provide a reconstructed signal X j ; receiver predictor means having variable prediction coefficients, for receiving said reconstructed signal and providing therefrom a predictor output comprising at least partially said receiver predicted value; said predictor means being arranged to derive each predictor coefficient using an equation consisting essentially of a decay term and a non-linear function having at least one set of arguments comprising a finite number of past values of said difference signal E j and having no arguments comprising the value of said reconstructed signal X j .

Claim 54

A receiver for an adaptive differential pulse code modulation system comprising an inverse quantizer for recovering a receiver quantized difference signal E j from a received numeric representation N j ; an adder for combining a receiver predicted value X j and a receiver quantized difference signal E j to provide a reconstructed signal X j ; receiver predictor means having variable prediction coefficients, for receiving said reconstructed signal and providing therefrom a predictor output comprising at least partially said receiver predicted value; said predictor means being arranged to derive each predictor coefficient using an equation consisting essentially of a decay term and a non-linear function having at least one set of arguments comprising a finite number of past values of said difference signal E j and having no arguments comprising the value of said reconstructed signal X j .

Claim 55

A receiver as defined in claim 41 or 42 wherein said predictor means has two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU28## where j is a particular sample period; δ 1 and δ 2 are positive values much smaller than 1; g 1 and g 2 and d are proper positive constants.

Claim 56

A receiver as defined in claim 43, wherein the first said predictor means provides a part only of the predicted value and said receiver further comprises: second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ) and a second adder for summing the output of the first-mentioned predictor means and the partial predicted value to provide said predicted value.

Claim 57

A receiver as defined in claim 43, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:8 and 1:4, respectively.

Claim 58

A receiver as defined in claim 45, wherein the constants g 1 and g 2 are substantially equal.

Claim 59

A receiver as defined in claim 46, wherein the constants δ 1 , δ 2 , g 1 and g 2 are substantially equal to 1/256, 1/128, 1/32 and 1/32, respectively.

Claim 60

A receiver as defined in claim 41 or 42, wherein said predictors each have two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU29##

Claim 61

A receiver as defined in claim 48, wherein the first said predictor means provides a part only of the predicted value and said receiver further comprises: second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ) and a second adder for summing the output of the first-mentioned predictor means and the partial predicted value to provide said predicted value.

Claim 62

A receiver as defined in claim 48, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:2√2 and unity, respectively.

Claim 63

A receiver as defined in claim 50, wherein the constants δ 1 , δ 2 , g 1 and g 2 are about 1/181, 1/90, 1/64 and 1/90, respectively.

Claim 64

A receiver as defined in claim 41, wherein the first said predictor means provides a part only of the predicted value and said receiver further comprises: second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predicted value (X jo ) and a second adder for summing the output of the first-mentioned predictor means and the partial predicted value to provide said predicted value.

Claim 65

A receiver for an adaptive differential pulse code modulation system comprising an inverse quantizer for recovering a receiver quantized difference signal E j from a received numeric representation N j ; an adder for combining a receiver predicted value X j and a receiver quantized difference signal E j to provide a reconstructed signal X j ; first receiver predictor means having variable prediction coefficients, for receiving said reconstructed signal X j and providing therefrom a predictor output (X jp ) comprising a part of said receiver predicted value; a feedback loop for applying said predicted value (X j ) to said first receiver summing means; second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predictor value (X jo ); a second summing means for summing the respective outputs (X jp and X jo ) of the first predictor means and the second predictor means to provide said predictor value X j ; third summing means for deriving the sum E' j of the quantized difference signal E j and the partial predicted value (X jo ) from said second predictor means; said first predictor means being arranged to derive its predictor value X jp in accordance with the equation: ##EQU30## wherein A i -A n are the predictor coefficient values defined by: ##EQU31## where i=the number of the particular predictor coefficient

Claim 66

A receiver for an adaptive differential pulse code modulation system comprising an inverse quantizer for recovering a receiver quantized difference signal E j from a received numeric representation N j ; an adder for combining a receiver predicted value X j and a receiver quantized difference signal E j to provide a reconstructed signal X j ; first receiver predictor means having variable prediction coefficients, for receiving said reconstructed signal X j and providing therefrom a predictor output (X jp ) comprising a part of said receiver predicted value; a feedback loop for applying said predicted value (X j ) to said first receiver summing means; second predictor means having variable coefficients and no feedback loop for providing from the regenerated difference signal (E j ) a partial predictor value (X jo ); a second summing means for summing the respective outputs (X jp and X jo ) of the first predictor means and the second predictor means to provide said predictor value X j ; third summing means for deriving the sum E' j of the quantized difference signal E j and the partial predicted value (X jo ) from said second predictor means; said first predictor means being arranged to derive its predictor value X jp in accordance with the equation: ##EQU30## wherein A i -A n are the predictor coefficient values defined by: ##EQU31## where i=the number of the particular predictor coefficient

Claim 67

=1. . . n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E' j is the sum of the quantized difference signal E j at time j and the output X jo of said second predictor means; A i j is the respective predictor coefficient at time point j; F i is a non-linear function; X j is the sum of the difference signal E j and the predicted value X j .

Claim 68

=1. . . n where n is the number of coefficients; δ i is a positive constant much smaller than one; g is a proper positive constant; E' j is the sum of the quantized difference signal E j at time j and the output X jo of said second predictor means; A i j is the respective predictor coefficient at time point j; F i is a non-linear function; X j is the sum of the difference signal E j and the predicted value X j .

Claim 69

A receiver as defined in claim 53, wherein each said first predictor has two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU32## where j is a particular sample period; δ 1 and δ 2 are positive values much smaller than 1; g 1 and g 2 and d are proper positive constants.

Claim 70

A receiver as defined in claim 54, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:8 and 1:4, respectively.

Claim 71

A receiver as defined in claim 55, wherein the constants g 1 and g 2 are substantially equal.

Claim 72

A receiver as defined in claim 56, wherein the constants δ 1 , δ 2 , g 1 and g 2 are substantially equal to 1/256, 1/128, 1/32 and 1/32, respectively.

Claim 73

A receiver as defined in claim 53, including predictors each having two predictor coefficients A 1 and A 2 derived in accordance with the equations: ##EQU33##

Claim 74

A receiver as defined in claim 58, wherein the constants δ 1 , δ 2 , g 1 and g 2 are determined such that the ratios δ 1 :g 1 and δ 2 :g 2 are about 1:2√2 and unity, respectively.

Claim 75

A receiver as defined in claim 59, wherein the constants δ 1 , δ 2 , g 1 and g 2 are about 1/181, 1/90, 1/64 and 1/90, respectively.