Four channel decoder with variable mixing of the output channels

Claim 2

A multisignal transmission apparatus comprising; a. means for converting two composite signals into four output signals, each of said output signals containing a separate dominant signal and at least two subdominant signals, b. four separate transmitting channels for respectively transmitting each of said output signals, c. means for arranging the phase of at least one subdominant signal in each of said output signals to be one hundred and eighty degrees out-of-phase with respect to the same subdominant signal contained in another of said output signals, d. means for producing at least one control signal by comparing the absolute magnitudes of said dominant signals in at least two of said transmitting channels, and e. variable mixing means connected between the other two of said transmitting channels which contain said out of phase subdominant signals, said variable mixing means being controlled with said control signal so as to mix said out of phase subdominant signals and thereby substantially cancel them.

Claim 3

A multisignal transmission apparatus as recited in claim 1, wherein said converting means comprises all-pass phase-shifting networks for giving said two composite signals a relative phase difference of 90*, a summing circuit for summing said phase-shifted two composite signals derived from said all-pass phase-shifting networks, and a subtracting circuit for differencing said phase-shifted two composite signals derived from said all-pass phase-shifting networks.

Claim 4

A multisignal transmission apparatus as recited in claim 1, wherein said variable mixing means comprises a variable impedance device to which said control signal is applied and the impedance of which is varied with the control signal.

Claim 5

A multisignal transmission apparatus as recited in claim 1, wherein said control signal producing means comprises detector circuit means for receiving a first pair of said output signals which contain the same subdominant signals and a second pair of signals corresponding to the other pair of said output signals which contain the same subdominant signals and comparing circuit means for separately comparing said first pair of signals and for comparing said second pair of signals, respectively, and to produce separate control signals representative of whether said pairs of signals contain subdominant signals which are in phase coincidence or in phase opposition.

Claim 6

A multisignal transmission apparatus as recited in claim 4, wherein said detector circuit means includes four input terminals for separately receiving said four output signals, each of said input terminals being connected to a separate full-wave rectifier circuit, and said comparing circuit includes a pair of subtracting circuits for subtracting the outputs from selected pairs of said full-wave rectifier circuits.

Claim 7

A multisignal transmission apparatus adapted to receive first and second composite signals LT and RT respectively containing dominant signals Lf and Rf in phase with each other and each including at least two subdominant signal components Lb and Rb, the apparatus comprising; a. circuit means including all-pass phase-shifting networks and combining networks for deriving first, second, third and fourth output signals containing in phase dominant signal components Lf, Rf, Lb and Rb, respectively, said first and fourth output signals also containing subdominant Lb and Rb signals with said Lb subdominant signal in each one of said first and fourth output signals being in phase opposition to said Rb subdominant signal in the other of said first and fourth output signals, said second and third output signals also containing subdominant Lf and Rf signals with said Lf subdominant signal in each one of said second and third output signals being in phase opposition to said Rf subdominant signal in the other of said second and third output signals, b. first, second, third and fourth channels for transmitting said respective first through fourth output signals, c. first and second variable mixing means connected between said first and fourth channels and between said second and third channels, respectively, for mixing said first and fourth and second and third output signals, respectively, d. control circuit means for comparing the sum and difference of said LT and RT composite signals to produce a first control signal when the sum of said LT and RT composite signals exceeds the difference of said LT and RT composite signals and a second control signal if the difference of said LT and RT composite signals exceeds the sum of said LT and RT composite signals, and e. means for supplying said first control signal to said first variable mixing means and said second control signal to said second variable mixing means so as to control the mixing conditions thereof in response to said first and second control signals, respectively.

Claim 8

A multisignal transmission apparatus adapted to receive first and second composite signals LT and RT respectively containing dominant signals Lf and Rf in phase with each other and each including at least two subdominant signal components Lb and Rb, the apparatus comprising; a. circuit means including all-pass phase-shifting networks and combining networks for deriving first, second, third and fourth output signals containing in phase dominant signal components Lf, Rf, Lb and Rb, respectively, said first and fourth output signals also containing subdominant Lb and Rb signals with said Lb subdominant signal in each one of said first and fourth output signals being in phase opposition to said Rb subdominant signal in the other of said first and fourth output signals, said second and third output signals also containing subdominant Lf and Rf signals with said Lf subdominant signal in each one of said second and third output signals being in phase opposition to said Rf subdominant signal in the other of said second and third output signals, b. first, second, third and fourth channels for transmitting said respective first through fourth output signals, c. first and second variable mixing means connected between said first and fourth channels and between said second and third channels, respectively, for mixing said first and fourth and second and third output signals, respectively, d. control circuit means for comparing the sum and difference of said LT and RT composite signals to produce a first control signal when the sum of said LT and RT composite signals exceeds the difference of said LT and RT composite signals and a second control signal if the difference of said LT and RT composite signals exceeds the sum of said LT and RT composite signals, and e. means for supplying said first control signal to said first variable mixing means and said second control signal to said second variable mixing means so as to control the mixing conditions thereof in response to said first and second control signals, respectively.

Claim 9

A multisignal transmission apparatus comprising; a. first, second, third and fourth channels for transmitting, respectively, first, second, third and fourth composite signals each of which contains separate dominant signals a, b, c and d, respectively, said first composite signal also containing two subdominant signal components corresponding to portions of said c and d signals, said second composite signal also containing two subdominant signal components corresponding to portions of said c and d signals, said third composite signal also containing two subdominant signal components corresponding to portions of said a and b signals, and said fourth composite signal also containing two subdominant signal components corresponding to portions of said a and b signals, b. means for arranging the phase of said c and d subdominant signal components in said first composite signal so as to be in phase opposition with respect to said c and d subdominant signal components, respectively, contained in said second composite signal, c. means for arranging the phase of said a and b subdominant signal components in said third composite signal so as to be in phase opposition with respect to said a and b subdominant signal components contained in said fourth composite signal, d. first and second variable mixing networks connected between said first and second channels, e. third and fourth variable mixing networks connected between said third and fourth channels, f. comparing control means including means for comparing the magnitudes of said dominant a and b signals and for producing a first control signal when a - b >0 and a second control signal when a - b <0; means for comparing the magnitudes of said dominant c and d signals and for producing a third control signal when c - d >0 and a fourth control signal when c - d <0; means for applying said first and second control signals to said third and fourth variable mixing networks, respectively, to thereby cancel said out of phase c and d subdominant signal components, respectively, and means for applying said third and fourth control signals to said first and second variable mixing means, respectively, to thereby cancel said out of phase a and b subdominant components, respectively.

Claim 10

A multisignal transmission apparatus comprising; a. first, second, third and fourth channels for transmitting, respectively, first, second, third and fourth composite signals each of which contains separate dominant signals a, b, c and d, respectively, said first composite signal also containing two subdominant signal components corresponding to portions of said c and d signals, said second composite signal also containing two subdominant signal components corresponding to portions of said c and d signals, said third composite signal also containing two subdominant signal components corresponding to portions of said a and b signals, and said fourth composite signal also containing two subdominant signal components corresponding to portions of said a and b signals, b. means for arranging the phase of said c and d subdominant signal components in said first composite signal so as to be in phase opposition with respect to said c and d subdominant signal components, respectively, contained in said second composite signal, c. means for arranging the phase of said a and b subdominant signal components in said third composite signal so as to be in phase opposition with respect to said a and b subdominant signal components contained in said fourth composite signal, d. first and second variable mixing networks connected between said first and second channels, e. third and fourth variable mixing networks connected between said third and fourth channels, f. comparing control means including means for comparing the magnitudes of said dominant a and b signals and for producing a first control signal when a - b >0 and a second control signal when a - b <0; means for comparing the magnitudes of said dominant c and d signals and for producing a third control signal when c - d >0 and a fourth control signal when c - d <0; means for applying said first and second control signals to said third and fourth variable mixing networks, respectively, to thereby cancel said out of phase c and d subdominant signal components, respectively, and means for applying said third and fourth control signals to said first and second variable mixing means, respectively, to thereby cancel said out of phase a and b subdominant components, respectively.

Claim 11

A multisignal transmission apparatus as recited in claim 6 wherein said control circuit means further comprises means for summing said LT and RT composite signals, means for subtracting said LT and RT composite signals, means for rectifying the outputs of said summing And subtracting means, and means for subtracting the rectified outputs to produce said first and second control signals.

Claim 12

A multisignal decoding apparatus comprising, first, second, third and fourth channels for transmitting first, second, third and fourth signals, respectively, as dominant signals, said first and fourth channels also containing oppositely phased subdominant signals corresponding to said second signal, said second and third channels also containing oppositely phased subdominant signals corresponding to said fourth signal, first comparing circuit means for producing at least a first control signal by comparison of the absolute magnitudes of at least said first and fourth dominant signals, first variable mixing means connected between said second and third channels for mixing said signals contained therein with each other so as to cancel said oppositely phased subdominant signals corresponding to at least one of said first and fourth dominant signals in response to said first control signal, second comparing circuit means for producing at least a second control signal by comparison of the absolute magnitudes of said second and third signals, and second variable mixing means connected between said first and fourth channels for mixing said signals contained therein with each other so as to cancel said oppositely phased subdominant signals corresponding to at least one of said second and third dominant signals in response to said second control signal.

Claim 13

A multisignal decoding apparatus comprising, first, second, third and fourth channels for transmitting first, second, third and fourth signals, respectively, as dominant signals, said first and fourth channels also containing oppositely phased subdominant signals corresponding to said second signal, said second and third channels also containing oppositely phased subdominant signals corresponding to said fourth signal, first comparing circuit means for producing at least a first control signal by comparison of the absolute magnitudes of at least said first and fourth dominant signals, first variable mixing means connected between said second and third channels for mixing said signals contained therein with each other so as to cancel said oppositely phased subdominant signals corresponding to at least one of said first and fourth dominant signals in response to said first control signal, second comparing circuit means for producing at least a second control signal by comparison of the absolute magnitudes of said second and third signals, and second variable mixing means connected between said first and fourth channels for mixing said signals contained therein with each other so as to cancel said oppositely phased subdominant signals corresponding to at least one of said second and third dominant signals in response to said second control signal.