Recorder and playback apparatus for pulse width modulated record

Claim 2

An information record comprising a tape having said information contained as width modulation of fixed depth grooves, said grooves comprised of first and second edges and extending generally in a direction of the width of said tape, whereby upon being illuminated said information is contained in light diffracted by said width modulated fixed depth grooves.

Claim 3

An information record according to claim 1 wherein said tape is transparent.

Claim 4

An information record according to claim 2 wherein said modulated grooves have equal spacing between said second edges of adjacent grooves.

Claim 5

An information record according to claim 3 wherein said fixed depth grooves are periodic and extend transversely of said tape at an angle of approximately 45 degrees to the longitudinal dimension of said tape.

Claim 6

A sound record comprising a transparent tape having sound information contained as width modulation of periodic fixed depth grooves extending generally in a direction of the width of said tape, whereby upon being illuminated said sound information is contained in light diffracted by said periodic width modulated fixed depth grooves.

Claim 7

A sound record comprising a transparent tape having sound information contained as width modulation of periodic fixed depth grooves extending generally in a direction of the width of said tape, whereby upon being illuminated said sound information is contained in light diffracted by said periodic width modulated fixed depth grooves.

Claim 8

A sound record according to claim 5 wherein the frequency of occurrEnce of said periodic grooves is greater than the highest frequency of said sound information.

Claim 9

A multiple channel sound record comprising a transparent tape including a first sound channel contained as width modulation of first grooves of fixed depth extending across said tape at a first angle measured in one direction from the longitudinal axis of said tape; and a second sound channel contained as width modulation of said grooves of fixed depth extending across said tape angularly disposed to said second grooves, whereby upon being illuminated sound information from said channels is contained in light diffracted by said first and second grooves.

Claim 10

A multiple channel sound record comprising a transparent tape including a first sound channel contained as width modulation of first grooves of fixed depth extending across said tape at a first angle measured in one direction from the longitudinal axis of said tape; and a second sound channel contained as width modulation of said grooves of fixed depth extending across said tape angularly disposed to said second grooves, whereby upon being illuminated sound information from said channels is contained in light diffracted by said first and second grooves.

Claim 11

A multiple channel sound record according to claim 7 wherein said grooves are periodic and the frequency of occurrence of said periodic grooves in each of said channels is greater than the highest frequency of sound information in said channels.

Claim 12

Apparatus for producing electrical signals from a multiple channel sound record including first and second sound channels contained as width modulation of respective first and second periodic grooves of fixed depth of said record extending across said record at respective angles measured in first and second directions from the direction of travel of said record, said first periodic grooves disposed at an angle to said second periodic grooves, comprising: a light source; means for forming said light into first and second relatively narrow beam portions, the elongated transverse cross sections of said beam portions having an angle between each other corresponding to the angle between said first and second periodic grooves of said record; means for directing said light to a plane; means for moving said record in said plane; light detecting means for detecting light diffracted by said first and second sound channels for producing electrical signals corresponding to said diffracted light; and means for separating sound information portions of said signals from portions of said signals representative of said first and second periodic grooves of said record.

Claim 13

Apparatus for producing electrical signals from a multiple channel sound record including first and second sound channels contained as width modulation of respective first and second periodic grooves of fixed depth of said record extending across said record at respective angles measured in first and second directions from the direction of travel of said record, said first periodic grooves disposed at an angle to said second periodic grooves, comprising: a light source; means for forming said light into first and second relatively narrow beam portions, the elongated transverse cross sections of said beam portions having an angle between each other corresponding to the angle between said first and second periodic grooves of said record; means for directing said light to a plane; means for moving said record in said plane; light detecting means for detecting light diffracted by said first and second sound channels for producing electrical signals corresponding to said diffracted light; and means for separating sound information portions of said signals from portions of said signals representative of said first and second periodic grooves of said record.

Claim 14

Apparatus for producing electrical signals corresponding to video and audio information contained in a record, said audio information being contained in a portion of said record adjacent video portions and comprising width modulation of periodic fixed depth grooves extending generally in a direction of the width of said sound record portion at an angle to the direction of movement of said record, comprising: a light source; means for moving said record relative to said light source; means for directing a first portion of said light for illuminating video portions of said record whereby video information is contained in light diffracted by said record; first detecting means disposed for detecting said light diffracted by video portions of said record for producing electrical signals corresponding to video information contained in said record; means for directing a second portion of said light for illuminating said audio information portion of said record whereby audio information is contained in light diffracted by said record; second detecting means disposed for detecting said light diffracted by audio portions of said record and for producing electrical signals corresponding to said light; and means coupled to said detecting means for separating audio information signals corresponding to said width modulation of said periodic grooves from signals corresponding to the periodic portions of said sound record.

Claim 15

Apparatus for producing electrical signals corresponding to video and audio information contained in a record, said audio information being contained in a portion of said record adjacent video portions and comprising width modulation of periodic fixed depth grooves extending generally in a direction of the width of said sound record portion at an angle to the direction of movement of said record, comprising: a light source; means for moving said record relative to said light source; means for directing a first portion of said light for illuminating video portions of said record whereby video information is contained in light diffracted by said record; first detecting means disposed for detecting said light diffracted by video portions of said record for producing electrical signals corresponding to video information contained in said record; means for directing a second portion of said light for illuminating said audio information portion of said record whereby audio information is contained in light diffracted by said record; second detecting means disposed for detecting said light diffracted by audio portions of said record and for producing electrical signals corresponding to said light; and means coupled to said detecting means for separating audio information signals corresponding to said width modulation of said periodic grooves from signals corresponding to the periodic portions of said sound record.

Claim 16

Apparatus for producing electrical signals corresponding to video and audio information contained in a record according to claim 10, wherein said record is a flexible transparent tape and said periodic grooves of said audio portion of said tape have a frequency of occurrence greater than the highest frequency of said audio information constituting the width modulation of said periodic grooves.

Claim 17

Apparatus for producing a sound record, wHerein said sound record is comprised of sound information contained as width modulation of periodic fixed depth grooves, comprising: a source of audio signals; a source of carrier waves; modulation means coupled to said audio signal and carrier wave source for producing a wave comprising said carrier wave pulse width modulated by said audio signals; a light source; an electro-optical modulator disposed to intercept light from said light source; means coupling said pulse width modulated wave to said modulator for controlling the light passing through said modulator in accordance with said pulse width modulated wave; and means for directing said light passing through said modulator to a plane suitable for containing a light sensitive medium whereby said pulse width modulated light is recorded on said medium.

Claim 18

Apparatus for producing a sound record, wHerein said sound record is comprised of sound information contained as width modulation of periodic fixed depth grooves, comprising: a source of audio signals; a source of carrier waves; modulation means coupled to said audio signal and carrier wave source for producing a wave comprising said carrier wave pulse width modulated by said audio signals; a light source; an electro-optical modulator disposed to intercept light from said light source; means coupling said pulse width modulated wave to said modulator for controlling the light passing through said modulator in accordance with said pulse width modulated wave; and means for directing said light passing through said modulator to a plane suitable for containing a light sensitive medium whereby said pulse width modulated light is recorded on said medium.