Quadraphonic reproducing system with gain riding logic

Claim 2

In apparatus for reproducing on four separate loudspeakers four separate channels of program information designated LF, Rf, Lb and Rb contained in first and second composite signals respectively including Lf and Rf as its predominant signal component and each including sub-dominant signal components Lb and Rb, and including signal-combining networks operative to derive from said first and second composite signals a third composite signal including a dominant signal Lb and sub-dominant signals Lf and Rf and a fourth composite signal including a dominant signal Rb and sub-dominant signals Lf and Rf, and means for applying said first, second, third and fourth composite signals to respective first, second, third and fourth gain control amplifiers connected to corresponding ones of said loudspeakers, a control circuit for enhancing the realism of the four channel sound produced by said apparatus, said control circuit comprising: first and second phase shift networks operative to position said first and second composite signals in phase-quadrature prior to application thereof to said signal-combining networks, first circuit means connected to receive said quadrature-related first and second composite signals and operative to produce first and second alternating current signals respectively representing the cross-correlation of said first and second and of said third and fourth composite signals over a predetermined time interval, first and second rectifying and time constant means respectively connected to receive and operative to convert said first and second alternating current signals to first and second unidirectional signals, second circuit means operative to subtract said first and second unidirectional signals from each other to produce first and second control signals, and means for applying said first control signal to said first and second gain control amplifiers and for applying said second control signal to said third and fourth gain control amplifiers.

Claim 3

Apparatus according to claim 1, wherein said first circuit means includes: means operative in response to said quadrature-related first and second composite signals to produce first, second, third and fourth auxiliary signals substantially corresponding to respective ones of said first, second, third and fourth composite signals, first and second multiplying circuits operative continuously to multiply said first and second and said third and fourth auxiliary signals, respectively, and first and second integrating means respectively operative to integrate the output signals from said first and second multiplying circuits over said predetermined time interval, thereby to produce integrated products of said first and second and of said third and fourth auxiliary signals.

Claim 4

Apparatus according to claim 1 wherein said predetermined time interval is approximately 6.7 milliseconds.

Claim 5

Apparatus for decoding first and second composite signals respectively containing predominant signals Lf and Rf to the extent they are present, and each containing two sub-dominant signal components Lb and Rb to the extent they are present, with the Lb and Rb components in one of said composite signals at a predetermined phase angle relative to the Lb and Rb components in the other of said composite signals, and with the Lb and Rb components in one of said composite signals leading and lagging, respectively, the Lb and Rb components in the other of said composite signals, said apparatus comprising: all-pass phase-shifting means operative to shift the phase of one of said composite signals relative to the other by said predetermined phase angle to position the Lb and Rb components in one composite signal substantially in phase coincidence or in phase opposition with the corresponding components in the other composite signal; combining networks oPerative to derive from the relatively phase-shifted composite signals from said phase-shifting means third and fourth composite signals respectively containing predominant signal components Lb and Rb; first, second, third and fourth gain control means connected to receive composite signals respectively containing predominant signal components Lf, Rf, Lb and Rb; and control circuit means connected to receive the relatively phase-shifted composite signals from said phase-shifting means and operative to produce a first unidirectional signal of one polarity or of opposite polarity when said Lb and Rb signals instantaneously appear therein in phase coincidence or in phase opposition, respectively, and to produce a second unidirectional signal of one polarity or of opposite polarity when said Lf and Rf signals instantaneously appear therein in phase coincidence or in phase opposition, respectively, subtracting circuit means operative to subtract said first and second unidirectional signals from each other to produce first and second control signals, and means for applying said first control signal to said first and second gain control means and for applying said second control signal to said third and fourth gain control means to control the gains thereof.

Claim 6

Apparatus for decoding first and second composite signals respectively containing predominant signals Lf and Rf to the extent they are present, and each containing two sub-dominant signal components Lb and Rb to the extent they are present, with the Lb and Rb components in one of said composite signals at a predetermined phase angle relative to the Lb and Rb components in the other of said composite signals, and with the Lb and Rb components in one of said composite signals leading and lagging, respectively, the Lb and Rb components in the other of said composite signals, said apparatus comprising: all-pass phase-shifting means operative to shift the phase of one of said composite signals relative to the other by said predetermined phase angle to position the Lb and Rb components in one composite signal substantially in phase coincidence or in phase opposition with the corresponding components in the other composite signal; combining networks oPerative to derive from the relatively phase-shifted composite signals from said phase-shifting means third and fourth composite signals respectively containing predominant signal components Lb and Rb; first, second, third and fourth gain control means connected to receive composite signals respectively containing predominant signal components Lf, Rf, Lb and Rb; and control circuit means connected to receive the relatively phase-shifted composite signals from said phase-shifting means and operative to produce a first unidirectional signal of one polarity or of opposite polarity when said Lb and Rb signals instantaneously appear therein in phase coincidence or in phase opposition, respectively, and to produce a second unidirectional signal of one polarity or of opposite polarity when said Lf and Rf signals instantaneously appear therein in phase coincidence or in phase opposition, respectively, subtracting circuit means operative to subtract said first and second unidirectional signals from each other to produce first and second control signals, and means for applying said first control signal to said first and second gain control means and for applying said second control signal to said third and fourth gain control means to control the gains thereof.

Claim 7

Apparatus according to claim 4 wherein said control circuit means includes circuit means operative in response to the relatively phase-shifted signals from said phase-shifting means to produce first and second alternating current signals respectively representing the cross-correlation of said first and second and of said third and fourth composite signals over a predetermined time interval, and first and second rectifying means respectively connected to receive and operative to convert said first and second alternating current signals to said first and said second unidirectional signals, respectively.

Claim 8

Apparatus according to claim 5 wherein said circuit means comprises first and second multiplying circuits respectively connected to receive and operative to continuously multiply signals substantially corresponding to said first and second composite signals and signals substantially corresponding to said third and fourth composite signals, and first and second integrating means respectively operative to integrate the output signals from said first and second multiplying circuits over said predetermined time interval.

Claim 9

Apparatus according to claim 6 wherein said predetermined time interval is approximately 6.7 milliseconds.

Claim 10

Apparatus according to claim 4 wherein said predetermined phase angle is substantially 90*.

Claim 11

In a sound system in which first, second, third and fourth audio information signals are carried on two channels as first and second composite signals respectively containing said first and second audio information signals to the extent they are present, and each containing said third and fourth audio information signals to the extent they are present, with the third and fourth signals in one of said composite signals at a predetermined phase angle relative to the third and fourth signals in the other of said composite signals, apparatus for decoding said composite signals to derive four output signals in which said first, second, third and fourth audio information signals are respectively predominant and to enhance the instantaneously present predominant signal, said apparatus comprising: phase-shifting means connected to receive said first and second composite signals and operative to shift the phase of one of said composite signals relative to the other by said predetermined phase angle to position the third and fourth audio information signals in one composite signal substantially in phase coincidence or in phase opposition with the corresponding audio information signals in the other composite signal; combining networks connected to receive and operative to dErive from the relatively phase-shifted composite signals from said phase-shifting means third and fourth composite signals respectively predominantly containing said third and fourth audio information signals; first, second, third and fourth gain control means connected to receive composite signals respectively predominantly containing said first, second, third and fourth audio information signals; and a control circuit including means connected to receive the relatively phase-shifted composite signals from said phase-shifting means and operative to produce a first unidirectional signal of one polarity or of opposite polarity when said third and fourth signals are instantaneously present therein in phase coincidence or in phase opposition, respectively, and to produce a second unidirectional signal of one polarity or of opposite polarity when said first and second signals are instantaneously present therein in phase or in phase opposition, respectively, subtracting circuit means operative to subtract said first and second unidirectional signals from each other to produce first and second control signals, and means for applying said first and second control signals to said first and second gain control means and to said third and fourth gain control means, respectively, to control the gains thereof.

Claim 12

In a sound system in which first, second, third and fourth audio information signals are carried on two channels as first and second composite signals respectively containing said first and second audio information signals to the extent they are present, and each containing said third and fourth audio information signals to the extent they are present, with the third and fourth signals in one of said composite signals at a predetermined phase angle relative to the third and fourth signals in the other of said composite signals, apparatus for decoding said composite signals to derive four output signals in which said first, second, third and fourth audio information signals are respectively predominant and to enhance the instantaneously present predominant signal, said apparatus comprising: phase-shifting means connected to receive said first and second composite signals and operative to shift the phase of one of said composite signals relative to the other by said predetermined phase angle to position the third and fourth audio information signals in one composite signal substantially in phase coincidence or in phase opposition with the corresponding audio information signals in the other composite signal; combining networks connected to receive and operative to dErive from the relatively phase-shifted composite signals from said phase-shifting means third and fourth composite signals respectively predominantly containing said third and fourth audio information signals; first, second, third and fourth gain control means connected to receive composite signals respectively predominantly containing said first, second, third and fourth audio information signals; and a control circuit including means connected to receive the relatively phase-shifted composite signals from said phase-shifting means and operative to produce a first unidirectional signal of one polarity or of opposite polarity when said third and fourth signals are instantaneously present therein in phase coincidence or in phase opposition, respectively, and to produce a second unidirectional signal of one polarity or of opposite polarity when said first and second signals are instantaneously present therein in phase or in phase opposition, respectively, subtracting circuit means operative to subtract said first and second unidirectional signals from each other to produce first and second control signals, and means for applying said first and second control signals to said first and second gain control means and to said third and fourth gain control means, respectively, to control the gains thereof.

Claim 13

In apparatus for reproducing on four sound reproduction devices adapted to be positioned at the left front, right front, left back and right back corners of a listening area a like number of audio information signals contained in first and second composite signals respectively containing predominant left front (Lf) and right front (Rf) signals to the extent they are present, and each containing sub-dominant left back (Lb) and right back (Rb) signals to the extent they are present, with the Lb and Rb components in one of said composite signals at a predetermined phase angle relative to the Lb and Rb components in the other of said composite signals and with the Lb and Rb components in one of said composite signals leading and lagging, respectively, the Lb and Rb components in the other of said composite signals, the combination comprising: an input circuit to which said first and second composite signals are applied including all-pass phase-shifting means operative to shift the phase of one of said composite signals relative to the other by said predetermined angle to position the Lb and Rb components in one composite signal from said phase-shifting means substantially in phase coincidence or in phase opposition with the corresponding components in the other composite signal from said phase-shifting means; signal combining means to which said relatively phase-shifted composite signals are applied and operative to produce third and fourth composite signals respectively containing predominant left back (Lb) and right back (Rb) signals; and signal coupling means for coupling said first, second, third and fourth composite signals to respective ones of said sound reproduction devices, said signal coupling means including control signal generating means connected to receive the composite signals from said phase-shifting means and operative to produce a first unidirectional signal of one polarity or of opposite polarity if Lb and Rb signals are instantaneously present therein in phase coincidence or in phase opposition, respectively, and to produce a second unidirectional signal of one polarity or of opposite polarity if Lf and Rf signals are instantaneously present in said third and fourth composite signals in phase coincidence or in phase opposition, respectively, subtracting circuit means operative to subtract said first and second unidirectional signals from each other to produce first and second control signals, first, second, third and fourth signal amplitude-modifying means connected to receive said first, second, third and fourth composite signals respectively containing predominant signal components Lf, Rf, Lb and Rb, and means for applying said first and second control signals to said first and second signal amplitude-modifying means and to said third and fourth signal amplitude-modifying means, respectively, to control the signal transmission characteristics thereof.

Claim 14

In apparatus for reproducing on four sound reproduction devices adapted to be positioned at the left front, right front, left back and right back corners of a listening area a like number of audio information signals contained in first and second composite signals respectively containing predominant left front (Lf) and right front (Rf) signals to the extent they are present, and each containing sub-dominant left back (Lb) and right back (Rb) signals to the extent they are present, with the Lb and Rb components in one of said composite signals at a predetermined phase angle relative to the Lb and Rb components in the other of said composite signals and with the Lb and Rb components in one of said composite signals leading and lagging, respectively, the Lb and Rb components in the other of said composite signals, the combination comprising: an input circuit to which said first and second composite signals are applied including all-pass phase-shifting means operative to shift the phase of one of said composite signals relative to the other by said predetermined angle to position the Lb and Rb components in one composite signal from said phase-shifting means substantially in phase coincidence or in phase opposition with the corresponding components in the other composite signal from said phase-shifting means; signal combining means to which said relatively phase-shifted composite signals are applied and operative to produce third and fourth composite signals respectively containing predominant left back (Lb) and right back (Rb) signals; and signal coupling means for coupling said first, second, third and fourth composite signals to respective ones of said sound reproduction devices, said signal coupling means including control signal generating means connected to receive the composite signals from said phase-shifting means and operative to produce a first unidirectional signal of one polarity or of opposite polarity if Lb and Rb signals are instantaneously present therein in phase coincidence or in phase opposition, respectively, and to produce a second unidirectional signal of one polarity or of opposite polarity if Lf and Rf signals are instantaneously present in said third and fourth composite signals in phase coincidence or in phase opposition, respectively, subtracting circuit means operative to subtract said first and second unidirectional signals from each other to produce first and second control signals, first, second, third and fourth signal amplitude-modifying means connected to receive said first, second, third and fourth composite signals respectively containing predominant signal components Lf, Rf, Lb and Rb, and means for applying said first and second control signals to said first and second signal amplitude-modifying means and to said third and fourth signal amplitude-modifying means, respectively, to control the signal transmission characteristics thereof.

Claim 15

Apparatus according to claim 10 wherein said control signal generating means includes circuit means operative to derive from the relatively phase-shifted composite signals from said phase-shifting means four auxiliary signals of substantially constant amplitude regardless of the amplitudes of said composite signals and substantially corresponding to respective ones of said first, second, third and fourth composite signals, circuit means operative in response to said auxiliary composite signals to produce first and second alternating current signals respectively representing the cross-correlation of the two output signals containing Lf and Rf as predominant components and of the two output signals containing Lb and Rb as predominant components, and rectifying circuit means connected to receive and operative to convert said first and second alternating current signals to said first and second unidirectional signals, respectively.

Claim 16

In apparatus for decoding first and second composite signals respectively containing predominant first and second independent audio information signals to the extent they are present and each containing sub-dominant third and fourth audio information signals to the extent they are present, with the third and fourth signals in one of said composite signals in a preselected phase-angle relationship with the third and fourth signals in the other of said composite signals, to produce first, second, third and fourth composite output signals respectively containing said first, second, third and fourth audio information signals as predominant signals for reproduction on respective sound-reproducing devices and including first, second, third and fourth transmission control means for coupling said first, second, third and fourth composite output signals to their respective sound-reproducing devices, a control circuit for adjusting said transmission control means, said control circuit comprising: means for shifting the phase of one of said composite signals relative to the other by said preselected phase-angle to position said third and fourth signals in the relatively phase-shifted composite signals either in-phase or in phase opposition, first circuit means connected to receive said relatively phase-shifted composite signals and operative to produce a first unidirectional control signal when said third and fourth signals appear therein either in phase or in phase opposition, signal-combining means connected to receive said relatively phase-shifted composite signals and operative to produce fifth and sixth composite signals substantially corresponding in signal content to said third and fourth composite output signals and in which said first and second independent signals, to the extent they are present, appear as sub-dominant signals either in phase or in phase opposition, second circuit means connected to receive said fifth and sixth composite signals and operative to produce a second unidirectional control signal when said first and second signals appear therein either in phase or in phase opposition, and means for applying said first control signal to said first and second transmission control means and for applying said second control signal to said third and fourth transmission control means.

Claim 17

In apparatus for decoding first and second composite signals respectively containing predominant first and second independent audio information signals to the extent they are present and each containing sub-dominant third and fourth audio information signals to the extent they are present, with the third and fourth signals in one of said composite signals in a preselected phase-angle relationship with the third and fourth signals in the other of said composite signals, to produce first, second, third and fourth composite output signals respectively containing said first, second, third and fourth audio information signals as predominant signals for reproduction on respective sound-reproducing devices and including first, second, third and fourth transmission control means for coupling said first, second, third and fourth composite output signals to their respective sound-reproducing devices, a control circuit for adjusting said transmission control means, said control circuit comprising: means for shifting the phase of one of said composite signals relative to the other by said preselected phase-angle to position said third and fourth signals in the relatively phase-shifted composite signals either in-phase or in phase opposition, first circuit means connected to receive said relatively phase-shifted composite signals and operative to produce a first unidirectional control signal when said third and fourth signals appear therein either in phase or in phase opposition, signal-combining means connected to receive said relatively phase-shifted composite signals and operative to produce fifth and sixth composite signals substantially corresponding in signal content to said third and fourth composite output signals and in which said first and second independent signals, to the extent they are present, appear as sub-dominant signals either in phase or in phase opposition, second circuit means connected to receive said fifth and sixth composite signals and operative to produce a second unidirectional control signal when said first and second signals appear therein either in phase or in phase opposition, and means for applying said first control signal to said first and second transmission control means and for applying said second control signal to said third and fourth transmission control means.

Claim 18

Apparatus according to claim 12, wherein said means for applying said control signals to said transmission control means comprises means for subtracting said first and second control signals from each other.

Claim 19

Apparatus according to claim 12, wherein said first circuit means includes a first multiplying circuit operative continuously to multiply said relatively phase-shifted first and second composite signals, and first integrating means operative to integrate the output signal from said first multiplying circuit, and wherein said second circuit means includes a second multiplying circuit operative continuously to multiply said fifth and sixth composite signals, and second integrating means operative to integrate the output signal from said second multiplying circuit.