Method of manufacturing BaPb1-x Bix O3 single crystal

Claim 2

An echo canceller associated with a data transmission modem, the modem utilizing amplitude and phase modulation, the modem including a transmit path and a receive path, such that an undesired echo signal appears in the receive path resulting from a carrier signal in the transmit path, the carrier signal having a phase and amplitude state at each modulation interval, the echo canceller comprising: (a) first input means coupled to the transmit path for receiving a digital representation of the carrier signal, the representation indicating for each modulation interval the phase and amplitude state of the carrier signal; (b) code conversion means coupled to receive the representation and having a plurality of parallel outputs, each of the parallel outputs providing one of the values +1, -1, and 0, so that the parallel outputs together provide distinct configurations D i (n) corresponding to the phase and amplitude states of the carrier signal, said distinct configurations satisfying the equation: E[D.sub.i (n)·D.sub.i,(n)]=0 where: the operator E represents mathematical expectation; n is an integer representing an instant of time; i and i' represent respective parallel outputs of the code conversion means and are integers between 1 and a number of the parallel outputs; i≠i'; and D i (n) and D i ,(n), are the values provided at the respective parallel outputs; (c) output means, coupled to the receive path, for providing an analog synthetic echo signal; (d) means, disposed within the receive path, for subtractively combining the analog synthetic echo signal and the undesired echo signal to produce a residual echo signal therefrom; (e) second input means coupled to the receive path, for supplying a digital representation of the residual echo signal; and (f) a plurality of adaptive filters, coupled to receive the distinct configurations from respective ones of the parallel outputs of the code conversion means and to receive the digital representation of the residual echo signal from the second input means, having respective outputs coupled with the output means of the echo canceller, and having coefficients which are adjusted in an iterative manner in order to minimize the mean square value of the residual echo signal.

Claim 3

The echo canceller of claim 1 wherein: a. the representation of the carrier signal corresponds to a signal space having eight points A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , and A 8 ; b. there are four adaptive filters; and c. the code conversion means produces the distinct configurations according to the following table: ______________________________________ D(n) A.sub.1 A.sub.2 A.sub.3 A.sub.4 A.sub.5 A.sub.6 A.sub.7 A.sub.8 ______________________________________ D.sub.1 (n) +1 0 0 0 -1 0 0 0 D.sub.2 (n) 0 +1 0 0 0 -1 0 0 D.sub.3 (n) 0 0 +1 0 0 0 -1 0 D.sub.4 (n) 0 0 0 +1 0 0 0 -1 ______________________________________

Claim 4

The echo canceller of claim 1 wherein: a. the representation of the carrier signal corresponds to a signal space having eight points A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , and A 8 ; b. there are four adaptive filters; and c. the code conversion means produces the distinct configurations according to the following table: ______________________________________ D(n) A.sub.1 A.sub.2 A.sub.3 A.sub.4 A.sub.5 A.sub.6 A.sub.7 A.sub.8 ______________________________________ D.sub.1 (n) +1 0 0 0 -1 0 0 0 D.sub.2 (n) 0 +1 0 0 0 -1 0 0 D.sub.3 (n) 0 0 +1 +1 0 0 -1 -1 D.sub.4 (n) 0 0 +1 -1 0 0 -1 +1 ______________________________________

Claim 5

The echo canceller of claim 1 wherein: a. the representation of the carrier signal corresponds to a signal space having sixteen points A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , A 8 , A 9 , A 10 , A 11 , A 12 , A 13 , A 14 , A 15 , and A 16 ; b. there are eight adaptive filters; and c. the code conversion means produces the distinct configurations according to the following table: __________________________________________________________________________ D(n) A.sub.1 A.sub.2 A.sub.3 A.sub.4 A.sub.5 A.sub.6 A.sub.7 A.sub.8 A.sub.9 A.sub.10 A.sub.11 A.sub.12 A.sub.13 A.sub.14 A.sub.15 A.sub.16 __________________________________________________________________________ D.sub.1 (n) 1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 D.sub.2 (n) 0 1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 D.sub.3 (n) 0 0 1 0 0 0 0 0 0 0 -1 0 0 0 0 0 D.sub.4 (n) 0 0 0 1 0 0 0 0 0 0 0 -1 0 0 0 0 D.sub.5 (n) 0 0 0 0 1 0 0 0 0 0 0 0 -1 0 0 0 D.sub.6 (n) 0 0 0 0 0 1 0 0 0 0 0 0 0 -1 0 0 D.sub.7 (n) 0 0 0 0 0 0 1 0 0 0 0 0 0 0 -1 0 D.sub.8 (n) 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 -1 __________________________________________________________________________

Claim 6

The echo canceller of claim 1 wherein: a. the representation of the carrier signal corresponds to a signal space having sixteen points A 1 , A 2 , A 3 , A 4 , A 5 , A 6 , A 7 , A 8 , A 9 , A 10 , A 11 , A 12 , A 13 , A 14 , A 15 , and A 16 ; b. there are four adaptive filters; and c. the code conversion means produces the distinct configurations according to the following table: __________________________________________________________________________ D(n) A.sub.1 A.sub.2 A.sub.3 A.sub.4 A.sub.5 A.sub.6 A.sub.7 A.sub.8 A.sub.9 A.sub.10 A.sub.11 A.sub.12 A.sub.13 A.sub.14 A.sub.15 A.sub.16 __________________________________________________________________________ D.sub.1 (n) 1 0 0 1 -1 0 0 -1 -1 0 0 -1 1 0 0 1 D.sub.2 (n) 1 1 0 0 1 1 0 0 -1 -1 0 0 -1 -1 0 0 D.sub.3 (n) 0 1 1 0 0 -1 -1 0 0 -1 -1 0 0 1 1 0 D.sub.4 (n) 0 0 1 1 0 0 1 1 0 0 -1 -1 0 0 -1 -1 __________________________________________________________________________

Claim 7

An echo canceller associated with a data transmission modem, the modem utilizing amplitude and phase modulation, the modem including a transmit path and a receive path, such that an undesired echo signal appears in the receive path resulting from a carrier signal in the transmit path, the carrier signal having a phase and amplitude state at each modulation interval, the echo canceller comprising: (a) first input means coupled to the transmit path for receiving a digital representation of the carrier signal, the representation indicating for each modulation interval the phase and amplitude state of the carrier signal; (b) code conversion means coupled to receive the representation and having a plurality of parallel outputs, each of the parallel outputs providing one of the values +1, -1, and 0, so that the parallel outputs together provide distinct configurations D i (n) corresponding to the phase and amplitude states of the carrier signal, said distinct configurations satisfying the equation: E[D.sub.i (n-q)·D.sub.i,(n-q')]=0 where: the operator E represents mathematical expectation; n is an integer representing an instant of time; i and i' represent respective parallel outputs of the code conversion means and are integers between 1 and a number of the parallel outputs; i≠i'; q and q' are integers between 1 and the number of the parallel outputs; and D i (n) and D i '(n) are the values provided at the respective parallel outputs; (c) output means, coupled to the receive path, for providing an analog synthetic echo signal; (d) means, disposed within the receive path for subtractively combining the analog synthetic echo signal and the undesired echo signal to produce a residual echo signal therefrom; (e) second input means, coupled to the receive path for supplying a digital representation of the residual echo signal; and (f) a plurality of adaptive filters, coupled to receive the distinct configurations from respective ones of the parallel outputs of the code conversion means and to receive the digital representation of the residual echo signal from the second input means, having respective outputs coupled with the output means of the echo canceller, and having coefficients which are adjusted in an iterative manner in order to minimize the mean square value of the residual echo signal.

Claim 8

An echo canceller associated with a data transmission modem, the modem utilizing amplitude and phase modulation, the modem including a transmit path and a receive path, such that an undesired echo signal appears in the receive path resulting from a carrier signal in the transmit path, the carrier signal having a phase and amplitude state at each modulation interval, the echo canceller comprising: (a) first input means coupled to the transmit path for receiving a digital representation of the carrier signal, the representation indicating for each modulation interval the phase and amplitude state of the carrier signal; (b) code conversion means coupled to receive the representation and having a plurality of parallel outputs, each of the parallel outputs providing one of the values +1, -1, and 0, so that the parallel outputs together provide distinct configurations D i (n) corresponding to the phase and amplitude states of the carrier signal, said distinct configurations satisfying the equation: E[D.sub.i (n-q)·D.sub.i,(n-q')]=0 where: the operator E represents mathematical expectation; n is an integer representing an instant of time; i and i' represent respective parallel outputs of the code conversion means and are integers between 1 and a number of the parallel outputs; i≠i'; q and q' are integers between 1 and the number of the parallel outputs; and D i (n) and D i '(n) are the values provided at the respective parallel outputs; (c) output means, coupled to the receive path, for providing an analog synthetic echo signal; (d) means, disposed within the receive path for subtractively combining the analog synthetic echo signal and the undesired echo signal to produce a residual echo signal therefrom; (e) second input means, coupled to the receive path for supplying a digital representation of the residual echo signal; and (f) a plurality of adaptive filters, coupled to receive the distinct configurations from respective ones of the parallel outputs of the code conversion means and to receive the digital representation of the residual echo signal from the second input means, having respective outputs coupled with the output means of the echo canceller, and having coefficients which are adjusted in an iterative manner in order to minimize the mean square value of the residual echo signal.

Claim 9

An echo canceller as claimed in claim 1 or 6 wherein the modem produces pairs of possible phase and amplitude states of the carrier, each pair corresponding to the same amplitude and to two phases differing by 180°, characterized in that said code conversion means is arranged to produce the distinct configurations for each pair of states such that the values provided at corresponding parallel outputs are of opposite sign.

Claim 10

An echo canceler as claimed in claim 1 or 6 characterized in that all adaptive filters are identical to a base transversal filter arranged for processing an input signal D(n) which assumes the value +1, -1 or 0 at the instants nT, where n is an integer with -∞<n<∞ and T is the modulation interval, the output values ε(n) of this base filter at the instants nT being calculated in accordance with the expression ##EQU25## coefficients C q of this base transversal filter are adjusted in accordance with the recursion formula C.sub.q (n+1)=C.sub.q.sup.i (n)+αe(n)D(n-q) where α is a coefficient small with respect to 1 and e(n) is a digital representation of the residual echo signal at the instant nT.

Claim 11

The echo canceller of claim 1 or 6 wherein: (a) the first input means comprises a plurality of parallel digital inputs at which a plurality of digital signals are received, the digital signals representing binary numbers which represent points in a signal space; (b) the code conversion means comprises a memory addressable by said digital signals to provide the distinct configurations.

Claim 12

The echo canceller of claim 1 or 6 wherein each distinct configuration comprises only one value of modulus 1, the other values all being 0.

Claim 13

The echo canceller of claim 1 or 6 wherein the distinct configurations have the property that upon forming all possible products of two values in each distinct configuration, the sum of all possible products for all configurations is zero.

Claim 14

The echo canceller of claim 1 or further comprising: a. an adder having a plurality of parallel inputs coupled to the respective outputs of the adaptive filters and an output at which a sum is provided; and wherein b. the output means comprises: digital-to-analog converter coupled to the output of the adder and having an output for providing the synthetic echo signal in analog form; and c. the second input means comprises: an analog-to-digital converter having an output for providing the residual echo signal in digital form to the adaptive filters.