Stereophonic recording systems with quadrature phase relation

Claim 2

In apparatus for modifying stereophonically related sound representative signals prior to application to a stereophonic record cutter for diminishing vertical modulation components without alternating the total energy of reproduced sound, the combination of: first and second input terminals for receiving a pair of stereophonically related signals; and circuit means connected to said first and second input terminals and operative to modify said stereophonically related signals and to convey said modified signals to a as record cutter; said circuit means including a pair of all-pass filters respectively connected to said first and second input terminals and operative to introduce and maintain a 90* electrical phase difference between said received stereophonically related signals at all frequencies of interest.

Claim 3

a first channel coupled to the signal providing means for passing selected first signals;

Claim 4

a first channel coupled to the signal providing means for passing selected first signals;

Claim 5

In apparatus for modifying stereophonically related sound representative signals prior to application to a monophonic record cutter for diminishing vertical modulation components without altering the total energy of reproduced sound, the combination of: first and second input terminals for receiving a pair of stereophonically related sound representative signals; circuit means connected to said first and second input terminals and operative to modify said stereophonically related signals; said circuit means including a pair of all-pass filters respectively connected to said first and second input terminals and operative to introduce and maintain a 90* electrical phase difference between said received stereophonically related signals at all frequencies of interest; and means connected to said filters for summing said modified signals prior to application to a monophonic record cutter.

Claim 6

In apparatus for modifying stereophonically related sound representative signals prior to application to a monophonic record cutter for diminishing vertical modulation components without altering the total energy of reproduced sound, the combination of: first and second input terminals for receiving a pair of stereophonically related sound representative signals; circuit means connected to said first and second input terminals and operative to modify said stereophonically related signals; said circuit means including a pair of all-pass filters respectively connected to said first and second input terminals and operative to introduce and maintain a 90* electrical phase difference between said received stereophonically related signals at all frequencies of interest; and means connected to said filters for summing said modified signals prior to application to a monophonic record cutter.

Claim 7

means for combining the lower frequency components of said first signal with a second stereophonic information representing signal;

Claim 8

means for combining the lower frequency components of said first signal with a second stereophonic information representing signal;

Claim 9

means for maintaining a phase difference between said lower frequency components of said first signal and at least the lower frequency components of said second stereophonic information representing signal so as to avoid cancellation of said lower frequency components; and

Claim 10

means for maintaining a phase difference between said lower frequency components of said first signal and at least the lower frequency components of said second stereophonic information representing signal so as to avoid cancellation of said lower frequency components; and

Claim 11

a second channel coupled to the signal providing means for passing selected second signals;

Claim 12

a second channel coupled to the signal providing means for passing selected second signals;

Claim 13

In a system for the handling of sound representative signals to be reproduced for listening, the combination comprising:

Claim 14

In a system for the handling of sound representative signals to be reproduced for listening, the combination comprising:

Claim 15

first and second output means connected to receive, respectively, the higher frequency components separated out of said first signal, and the lower frequency components of said first signal combined with said second signal.

Claim 16

first and second output means connected to receive, respectively, the higher frequency components separated out of said first signal, and the lower frequency components of said first signal combined with said second signal.

Claim 17

In a system for the handling of sound representative signals to be reproduced for listening, the combination comprising means for providing signals representative of stereophonically detected sounds, a first channel coupled to the signal providing means for passing selected first signals, a second channel coupled to the signal providing means for passing selected second signals, phase shift means connected with one of said channels for placing in substantial quadrature phase relationship at least a portion of the selected first signals with respect to the selected second signals, and means connected with both channels for receiving signals in substantial quadrature phase relationship to provide a combined output for subsequent reproduction of sound, the phase shift means including means connected with the first channel for separating higher and lower frequencies of the selected first signals and for placing the separated lower frequencies in substantial quadrature phase relationship with the selected second signals, and the means to provide a combined output including means for combining the separated lower frequencies with the selected second signals of said second channel.

Claim 18

In a system for the handling of sound representative signals to be reproduced for listening, the combination comprising means for providing signals representative of stereophonically detected sounds, a first channel coupled to the signal providing means for passing selected first signals, a second channel coupled to the signal providing means for passing selected second signals, phase shift means connected with one of said channels for placing in substantial quadrature phase relationship at least a portion of the selected first signals with respect to the selected second signals, and means connected with both channels for receiving signals in substantial quadrature phase relationship to provide a combined output for subsequent reproduction of sound, the phase shift means including means connected with the first channel for separating higher and lower frequencies of the selected first signals and for placing the separated lower frequencies in substantial quadrature phase relationship with the selected second signals, and the means to provide a combined output including means for combining the separated lower frequencies with the selected second signals of said second channel.

Claim 19

phase shift means connected with one of said channels for placing in substantial quadrature phase relationship at least a portion of the selected first signals with respect to the selected second signals to prevent subsequent substantial alterations of combined sounds resulting from concurrent signal portions in the first and second channel; and

Claim 20

phase shift means connected with one of said channels for placing in substantial quadrature phase relationship at least a portion of the selected first signals with respect to the selected second signals to prevent subsequent substantial alterations of combined sounds resulting from concurrent signal portions in the first and second channel; and

Claim 21

In a system for the handling of sound representative signals to be reproduced for listening, the combination comprising means for providing signals representative of stereophonically detected sounds, a first channel coupled to the signal providing means for passing selected first signals, a second channel coupled to the signal providing means for passing selected second signals, phase shift means connected with one of said channels for placing in substantial quadrature phase relationship at least a portion of the selected first signals with respect to the selected second signals, and means connected with both channels for receiving signals in substantial quadrature phase relationship to provide a combined output for subsequent reproduction of sound, the means to provide a combined output comprising adding means connected with both channels to add together the selected first and second signals for the production of a monaural output.

Claim 22

In a system for the handling of sound representative signals to be reproduced for listening, the combination comprising means for providing signals representative of stereophonically detected sounds, a first channel coupled to the signal providing means for passing selected first signals, a second channel coupled to the signal providing means for passing selected second signals, phase shift means connected with one of said channels for placing in substantial quadrature phase relationship at least a portion of the selected first signals with respect to the selected second signals, and means connected with both channels for receiving signals in substantial quadrature phase relationship to provide a combined output for subsequent reproduction of sound, the means to provide a combined output comprising adding means connected with both channels to add together the selected first and second signals for the production of a monaural output.

Claim 23

means connected with both channels for receiving the signals in substantial quadrature phase relationship to provide outputs from the channels representative of the sound subsequently to be reproduced and with sAid selected first signals maintained in said substantial quadrature phase relationship.

Claim 24

means connected with both channels for receiving the signals in substantial quadrature phase relationship to provide outputs from the channels representative of the sound subsequently to be reproduced and with sAid selected first signals maintained in said substantial quadrature phase relationship.

Claim 25

In apparatus for producing stereophonic signals suitable for recording as angularly displaced forms of modulation in a record groove, the combination of;

Claim 26

In apparatus for producing stereophonic signals suitable for recording as angularly displaced forms of modulation in a record groove, the combination of;

Claim 27

Apparatus as defined in claim 6 in which the first stereophonic information representing signal is the difference between two stereophonic signals and is to be recorded as vertical groove modulation, and the second stereophonic information representing signal is the sum of said two stereophonic signals and is to be recorded as lateral groove modulation.

Claim 28

Apparatus as defined in claim 7 in which said separating means comprises high, middle and low pass filters means for separating the first stereophonic information representing signal into high, middle and low frequency components, together with means for producing substantially quadrature phase shift of said low frequency components, means for voltage dividing said middle frequency components into two parts and means for subjecTing one of said two parts to a time delay; the combining means combines the phase shifted low frequency components and the time delayed middle frequency components of said first stereophonic information representing signal with said second stereophonic information representing signal; and the first and second output means are connected to receive, respectively, a first output signal comprising said phase shifted low frequency components and time delayed portion of middle frequency components of said second signal and said first signal, and a second output signal comprising an undelayed portion of said middle frequency components, and the high frequency components of the first stereophonic information representing signal.

Claim 29

Apparatus as defined in claim 7 in which the phase difference maintaining means includes all-pass filter means interposed in the paths of said first and second stereophonic information representing signals, respectively.

Claim 30

Apparatus as defined in claim 9 in which said separating means comprises constant resistance high and low pass filter means for separating the first stereophonic information representing signal into higher and lower frequency components.

Claim 31

Apparatus as defined in claim 10 in which the phase difference maintaining means includes means for subjecting said second stereophonic information representing signal to substantially the same phase shift as that produced by said low pass filter means.

Claim 32

Apparatus as defined in claim 11 in which the crossover points of said high and low pass filter means are adjustable over a range of value.

Claim 33

Apparatus as defined in claim 12 together with recording means connected to said output means for recording the higher frequency components separated out of said first stereophonic information representing signal as vertical modulation of a record groove, and for recording the combination of the lower frequency components of said first stereophonic information representing signal and said second stereophonic information representing signal as lateral modulation of a record groove.

Claim 34

Apparatus as defined in claim 13 together with recording means connected to said output means for recording said first output signal as lateral modulation of a record groove, and for recording said second output signal as vertical modulation of a record groove.