US 6,704,369 B1Granted

Apparatus and method for signal separation and recording medium for the same

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorsNaoto Kawasaki, Hirokazu Shimada, Tsuyoshi Usagawa, Yasuyuki Shimada, Masanao Ebata

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Abstract

A signal separation apparatus is capable of extracting original signals of two different systems with a high quality from received signals containing the original signals superposed each other in the course of transmission. In signal transmission from senders to receiver equipment, the signals to be sent separately are susceptible to mutual interference and superposition with given amplification factors in the course of transmission through respective transmission channels to such an extent that these signals can no more be discerned from each other by a receiver. For restoring the original signals of different sources from the received signals with high fidelity, characteristics of the transmission channels are estimated by means of an evaluation function unit operatable with autocorrelation calculation, and the characteristics of filter elements of a signal separation circuit incorporated in the signal separation apparatus are determined on the basis of the results of the estimation to thereby allow the original signals of two sources to be restored from the mutually superposed state.

Claims6

Dependent claims

In a signal transmission/reception system in which first and second signals originating in signal sources of two systems are transmitted to a receiver equipment provided with two input facilities, said first and second signals undergoing mutual interference due to crosstalk in their course of being transmitted through transmission channels section and being inputted to the respective input facilities of said receiver equipment,

said receiver equipment comprises a signal separation apparatus comprising a signal separation section and an evaluation function calculating section,
wherein said signal separation section comprises:
first and second filter means each of a variable tap coefficient type for performing filtering processing on a first input signal;
third and fourth filter means each of a variable tap coefficient type for performing filtering processing on a second input signal;
first difference calculation means for determining arithmetically difference between outputs of said first and third filter means;
second difference calculation means for determining arithmetically difference between outputs of said second and fourth filter means;
fifth filter means of a variable tap coefficient type for performing filtering processing on an output signal of said first difference calculation means;
and
sixth filter means of a variable tap coefficient type for performing filtering processing on an output signal of said second difference calculation means;
and
wherein said evaluation function calculation section comprises:
first autocorrelation calculation means for determining arithmetically an inverse sign value of autocorrelation of an output signal of said fifth filter means;
second autocorrelation calculation means for determining arithmetically an inverse sign value of autocorrelation of an output signal of said sixth filter means;
addition means for adding together output values of said first and second autocorrelation calculation means;
absolute-value calculation means for determining an absolute value of an added output value of said addition means;
square calculation means for determining arithmetically a squared value of an absolute value outputted from said absolute value calculation means;
and
minimum value decision means for determining characteristics values of said transmission channels to obtain a minimum value from evaluation function values output from the square calculation means wherein the evaluation function values are determined arithmetically with respect to optional characteristics values of said transmission channels.

15 more elements

A method of separating first and second sequence signals input from transmission channels or paths, comprising the steps of:

(a) performing filtering processing on said first input signal with first and second filter means and performing processing on said second input signal with third and fourth filter means wherein said first, second, third and fourth filter means have respective controllable tap coefficient values in a frequency-based notation;
(b) performing difference calculation processings on output signals of said first filter means and said third filter means by first difference calculation means while performing difference calculation proceedings on output signals of said second filter means and said fourth filter means by second difference calculation means;
(c) performing filtering processing on output signals of said first and second difference calculation means, respectively, by fifth and sixth filter means each with a controllable tap coefficient value;
(d) determining arithmetically an inverse sign value of autocorrelation of an output signal of said fifth filter means by first autocorrelation calculation means while determining arithmetically an inverse sign value of autocorrelation of an output signal of said sixth filter means by second autocorrelation calculation means;
(e) adding together output signals of the first and second autocorrelation calculation means by addition means;
(f) determining arithmetically an absolute value of an output signal of said addition means by absolute value calculation means;
(g) determining arithmetically a square of an output absolute value of said absolute value calculation means by square calculation means;
(h) determining selectively a combination of tap coefficient values of said first, second, third and fourth filter means, respectively, so as to select a minimum evaluation function value in evaluation function values outputs of said square calculation means determined with optional tap coefficient values of said first, second, third and fourth filter means in a frequency-based notation;
(i) performing filtering processings by said first, second, third and fourth filter means with a combination of tap coefficient values determined in said step (h);
(j) performing difference calculation processing on output signals of said first and third filter means by said first difference calculation means, while performing difference calculation processing on output signals of said second and fourth filter means by said second difference calculation means;
and
(k) performing filtering processings on output values of said first and second difference calculation means, respectively, by said fifth and sixth filter means each an updated tap coefficient value,
wherein said updated tap coefficient value mentioned in said step (k) is given by following Expression:
1 α 1 ′ ⁡ ( ω ) ⁢ α 2 ′ ⁡ ( ω ) - β 1 ′ ⁡ ( ω ) ⁢ β 2 ′ ⁡ ( ω )
where α2′(ω) represents the tap coefficient value of said first filter means determined in said step (h),
−β1′(ω) represents the tap coefficient value of said second filter means determined in said step (h),
−β2′(ω) represents the tap coefficient value of said third filter means determined in said step (h),
α1′(ω) represents the tap coefficient value of said fourth filter means determined in said step (h).

15 more elements

A method of separating first and second sequence signals input from transmission channels or paths, comprising the steps of:

(a) performing filtering processing on said first input signal with first and second, filter means and performing filtering processing on said second input signal with third and fourth filter means wherein said first, second, third and fourth filter means have respective controllable tap coefficient values in a frequency-based notation;
(b) performing difference calculation processings on output signals of said first filter means and said third filter means by first difference calculation means while performing difference calculation processings on output signals of said second filter means and said fourth filter means by second difference calculation means;
(c) performing filtering processing on output signals of said first and second difference calculation means respectively by fifth and sixth filter means each with a controllable tap coefficient value;
(d) determining arithmetically an inverse sign value of autocorrelation of an output signal of said fifth filter means by first autocorrelation calculation means while determining arithmetically an inverse sign value of autocorrelation of an output signal of said sixth filter means by second autocorrelation calculation means;
(e) adding together output signals of the first and second autocorrelation calculation means by addition means;
(f) determining arithmetically an absolute value of an output signal of said addition means by absolute value calculation means;
(g) determining arithmetically a square of an output absolute value of said absolute value calculation means by square calculation means;
(h) determining selectively a combination of frequency components of tap coefficient values of said first, second, third and fourth filter means, respectively, within a predetermined range so as to select a minimum evaluation function value in evaluation function values outputs of said square calculation means determined with optional tap coefficient values of said first, second, third and fourth filter means in a frequency-based notation;
(i) performing filtering processing by said first, second, third and fourth filter means with a combination of tap coefficient values determined in said step (h);
(j) performing difference calculation processing on output signals of said first and third filter means by said first difference calculation means, while performing difference calculation processing on output signals of said second and fourth filter means by said second difference calculation means;
and
(k) performing filtering processings on output values of said first and second difference calculation means, respectively, by said fifth and sixth filter means each with an updated combination of tap coefficient value,
wherein said updated tap coefficient value mentioned in said step (k) is given by the following Expression:
1 cos ⁢ ⁢ θ ′ ⁡ ( ω ) ⁢ cos ⁢ ⁢ φ ′ ⁡ ( ω ) - sin ⁢ ⁢ θ ′ ⁡ ( ω ) ⁢ sin ⁢ ⁢ φ ′ ⁡ ( ω )
where θ′(ω) and φ′(ω) represent the tap coefficient value frequency components,
said predetermined range recited in said step (h) is given by from −π/2 to π/2, inclusive,
cos φ′(ω) represents the tap coefficient value of said first filter means determined in said step (h),
−sin θ′(ω) represents the tap coefficient value of said second filter means determined in said step (h),
−sin φ′(ω) represents the tap coefficient value of said third filter means determined in said step (h), and
cos θ′(ω) represents the tap coefficient value of said fourth filter means determined in said step (h).

17 more elements

A storage medium recording in the form of a program a signal separation method of processing by two input system to separate two original sequence signals subjected to mutual superposition in transmission channels or paths, thereby restoring the original sequence signals, said method comprising steps of:

(a) performing filtering processing on said first input signal with first and second, filter means and performing filtering processing on said second input signal with third and fourth filter means wherein said first, second, third and fourth filter means have respective controllable tap coefficient values in a frequence-based notation;
(b) performing difference calculation processings on output signals of said first filter means and said third filter means by first difference calculation means while performing difference calculation processings on output signals of said second filter means and said fourth filter means by second difference calculation means;
(c) performing filtering processing on output signals of said first and second difference calculation means, respectively, by fifth and sixth filter means each with a controllable tap coefficient value;
(d) determining arithmetically an inverse sign value of autocorrelation of an output signal of said fifth filter means by first autocorrelation calculation means while determining arithmetically an inverse sign value of autocorrelation of an output signal of said sixth filter means by second autocorrelation calculation means;
(e) adding together output signals of the first and second autocorrelation calculation by addition means;
(f) determining arithmetically an absolute value of an output signal of said addition means by absolute value calculation means;
(g) determining arithmetically a square of an output absolute value of said absolute value calculation means by square calculation means;
(h) determining selectively a combination of tap coefficient values of said first, second, third and fourth filter means, respectively, so as to select a minimum evaluation function value in evaluation function values outputs of said square calculation means determined with optional tap coefficient values of said first, second, third and fourth filter means in a frequency-based notation;
(i) performing filtering processings by said first, second, third and fourth filter means with a combination of tap coefficient values determined in said step (h);
(j) performing difference calculation processing on the output signals of said first and third filter means by said first difference calculation means, while performing difference calculation processing on output signals of said second and fourth filter means by said second difference calculation means;
and
(k) performing filtering processings on the output values of said first and second difference calculation means, respectively, by said fifth and sixth filter means each with an updated combination of tap coefficient value,
wherein said updated tap coefficient value mentioned in said step (k) is given by following Expression:
1 α 1 ′ ⁡ ( ω ) ⁢ α 2 ′ ⁡ ( ω ) - β 1 ′ ⁡ ( ω ) ⁢ β 2 ′ ⁡ ( ω )
where α2′(ω) represents the tap coefficient value of said first filter means determined in said step (h),
−β1′(ω) represents the tap coefficient value of said second filter means determined in said step (h),
−β2′(ω) represents the tap coefficient value of said third filter means determined in said step (h),
α1′(ω) represents the tap coefficient value of said fourth filter means determined in said step (h).

15 more elements

(a) performing filtering processing on said first input signal with first and second filter means and performing filtering processing on said second input signal with third and fourth filter means wherein said first, second, third and fourth filter means have respective controllable tap coefficient values in a frequency-based notation;
(b) performing difference calculation processings on output signals of said first filter means and said third filter means by first difference calculation means while performing difference calculation processings on output signals of said second filter means and said fourth filter means by second difference calculation means;
(c) performing filtering processing on output signals of said first and second difference calculation means respectively by fifth and sixth filter means each with a controllable tap coefficient value;
(d) determining arithmetically an inverse sign value of autocorrelation of an output signal of said fifth filter means by first autocorrelation calculation means while determining arithmetically an inverse sign value of autocorrelation of an output signal of said sixth filter means by second autocorrelation calculation means;
(e) adding together output signals of the first and second autocorrelation calculation means by addition means;
(f) determining arithmetically an absolute value of an output signal of said addition means by absolute value calculation means;
(g) determining arithmetically a square of an output absolute value of said absolute value calculation means by square calculation means;
(h) determining selectively a combination of frequency components of tap coefficient values of said first, second, third and fourth filter means, respectively, within a predetermined range so as to select a minimum evaluation function value in evaluation function values outputs of said square calculation means determined with optional tap coefficient values of said first, second, third and fourth filter means in a frequency-based notation;
(i) performing filtering processing by said first, second, third and fourth filter means with a combination of tap coefficient values determined in said step (h);
(j) performing difference calculation processing on the output signals of said first and third filter means by said first difference calculation means, while performing difference calculation processing on output signals of said second and fourth filter means by said second difference calculation means;
and
(k) performing filtering processings on output values of said first and second difference calculation means, respectively, by said fifth and sixth filter means each with an updated combination of tap coefficient value,
wherein said updated tap coefficient value mentioned in said step (k) is given by the following Expression:
1 cos ⁢ ⁢ θ ′ ⁡ ( ω ) ⁢ cos ⁢ ⁢ φ ′ ⁡ ( ω ) - sin ⁢ ⁢ θ ′ ⁡ ( ω ) ⁢ sin ⁢ ⁢ φ ′ ⁡ ( ω )
where θ′(ω) and φ′(ω) represent the tap coefficient value frequency components,
said predetermined range recited in said step (h) is given by from −π/2 to π/2, inclusive,
cos φ′(ω) represents the tap coefficient value of said first filter means determined in said step (h),
−sin θ′(ω) represents the tap coefficient value of said second filter means determined in said step (h),
−sin φ′(ω) represents the tap coefficient value of said third filter means determined in said step (h), and
cos θ′(ω) represents the tap coefficient value of said fourth filter means determined in said step (h).

17 more elements

Dependencies are inferred from the claim text.