Abstract: Apparatus for compensating for the absence of signals among a plurality of correlated signals, which occur simultaneously and which have carrier components, is disclosed herein. Such apparatus comprises detector means responsive to the absence of the carrier for longer than a predetermined time for selectively connecting output signals from channels where the carriers are present to the outputs of those channels where carriers are absent. The apparatus of the invention operates in real time without delay devices. Preferably, the invention is embodied in an apparatus for reproducing magnetically recorded, stereophonic signals, functioning to prevent dropouts from affecting the quality of the output signals and the sound corresponding thereto.

Abstract: Disclosed herein is a method and apparatus for producing color transparencies on a recording element comprising an additive color filter screen having disposed thereon a coating of a visible light-transmissive, invisible light-sensitive, silverless material, preferably a diazo or vesicular material. The method comprises the steps of imagewise exposing a panchromatic auxiliary layer, e.g. a photoconductive layer, to a multicolored object, such exposure being made through the recording element of the invention. This step acts to produce in the auxiliary layer a monochrome image containing color image information of the multicolored object. Next, the silverless material is exposed to invisible actinic radiation, such exposure being made through the monochrome image formed in or on the panchromatic auxiliary layer. This step serves to transfer the color image information from the auxiliary layer to the silverless layer of the recording element.

Abstract: A magnetic recording which is useful as a mirror image duplication video tape master is made from another magnetic recording by anhysteretic transfer at a temperature at which the coercive force of the master is much less than the coercive force of the other recording. Preferably, the magnetic recording layer of the master comprises fine particles of a manganese bismuth alloy, the coercivity of which decreases with decreasing temperature, and the other record comprises a magnetic recording layer having a coercivity which increases with decreasing temperature. The master record may subsequently be used to duplicate copies of the recording by anhysteretic transfer to a copy record having a coercive force which, at the temperature at which the transfer is made (typically room temperature), is substantially lower than the coercive force of the master.

Abstract: In accordance with the present invention, the optical characteristics of a thermal deformation record device are so altered that the device can be read back using the same beam as was used for recording. Moreover, the read beam can be used for playback at an arbitrarily high power level to enhance the signal-to-noise ratio of the recovered signal and yet not damage the deformation recording.

Abstract: To provide high intensity, uniform and specular illumination over a relatively large area, the present invention provides a specially configured reflector and a radiation source so positioned within the reflector that an apparent source is produced comprising the true source plus a spherical array of virtual images of the source.

Abstract: In accordance with a presently preferred embodiment of the invention, a servo control loop is disclosed using optical feedback to control the movement of a small, lightweight scanning mirror. The optical feedback is accomplished by reflecting radiation from the scanning mirror and imaging such radiation onto a pair of radiation detectors. An optical element having alternate relatively transparent and opaque regions is disposed in the optical path between the scanning mirror and the detectors to modulate in phase quadrature the intensity of radiation beams received by the detectors. The output signals from the detectors are used to develop a feedback signal to close the servo loop.

Abstract: Apparatus and method are disclosed for use in replicating information from a master record carrier, such as a videodisc, onto a replicate material in web form. In a preferred embodiment, the disclosed replication apparatus comprises supply, exposure and takeup chambers. A web cleaning device in the supply chamber cleans the replicate material of foreign particles. In the exposure chamber, the replicate material and a master record carrier are brought into close contact in order to make a contact print exposure. The exposed replicate material is stored in the takeup chamber.

Abstract: Facsimile recording on a video disc, wherein a document such as a bank check is recorded as a frame of video information, generally requires that the frame of recorded information be displayed or transformed into a hard copy reproduction of the original document. In accordance with a presently preferred embodiment of the invention, the frame of video information is recorded on a video disc as two fields of interlaced lines recorded on adjacent circular tracks. Upon playback, the circular tracks are alternately read to produce the customary video display of two interlaced fields. To provide a hard copy reproduction of the original document, the circular tracks are simultaneously read and the resultant signal fed to a signal processing circuit. The output of the signal processing circuit comprises, in alternation, lines of video information from each field. This output signal is fed to a printer device which prints, line-by-line, a hard copy reproduction of the original document.

Abstract: Apparatus and method are disclosed for contact printing information from a master record carrier onto a replicate material of a type that emits gas during the contact print exposure (e.g., a diazo-film emulsion). It has been discovered that the emitted gas acts as an efficient lubricant of the master-replicate interface and contributes to relative movement between the master record carrier and the replicate material during the contact print exposure. In the case of videodisc replication, wherein video information is recorded in the form of billions of micron-sized apertures, such relative movement severely degrades the replicated imagery. To limit such relative movement, a preferred embodiment of the present invention provides contact printing apparatus, including a specially filtered exposing source, that substantially eliminates relative movement between the master record carrier and the replicate material.

Abstract: In accordance with a presently preferred embodiment of the invention, a source of radiation produces a pair of tracking spots focussed on a record carrier and nominally disposed toward opposite sides of a record track on the record carrier. After interaction with the record carrier, each of the tracking spots is detected to produce respective tracking signals. The components of each tracking signal which correspond to the information signal recorded on the record track are compared and a tracking error signal is produced based upon such comparison. By so producing the tracking error signal, proper tracking can be maintained irrespective of the polarity of the record carrier.

Abstract: Video information is commonly recorded on a master record device such as a video disc by focussing a modulated recording beam on the master disc and rotating the disc relative to the focussed recording beam. During exposure, the recording beam travels across the rotating master disc so that a spiral track of video information is recorded. Because of the extremely small depth of focus, typically less than a micron, focus maintenance is simplified if the master disc recording surface is optically flat. This requirement has led to the use of a relatively expensive master video disc comprised of optically polished glass, quartz or other rigid material. In accordance with the present invention, a method of recording video information on a master disc is provided which permits the use of an inexpensive flexible master disc comprised of ESTAR or other similar material, and yet which enables an extremely small depth of focus to be accurately maintained.

Abstract: Apparatus and method are disclosed for use in contact printing information from a master record carrier onto a replicate material of a type that emits a gas during the contact print exposure (e.g., a diazo film emulsion). Even though the master record carrier and the replicate material are pressed together by a pressure pad (e.g., a rubber diaphragm), it has been discovered that the emitted gas causes the master and replicate devices to separate slightly and that strain forces in the pressure pad are transmitted to the replicate material causing relative movement of the master record carrier and the replicate material during the contact print exposure. To limit such relative movement, a preferred embodiment of the present invention provides an isolating member disposed between the master-replicate sandwich and the pressure pad.

Abstract: Method and apparatus for recording a frame, comprising two fields, of document information on a disc storage device are described. The video signals corresponding to the two fields are used to amplitude modulate quadrature components of a single carrier frequency, each field modulating its own quadrature component. The quadrature amplitude modulated (QAM) carrier components are vectorially combined, the resultant being then angularly modulated on a high frequency carrier which is recorded on the disc storage device. In a preferred embodiment, a frame of information is recorded on the disc storage device along a single closed circular track. The present invention also provides methods for playing back the single track of recorded information for field-sequential video display, hard copy reproduction by a dual-line printer, or hard copy reproduction by a line-sequential printer.

Abstract: In certain types of printing applications (for example optical or magnetic contact printing) wherein it is desired to transfer imagery from a master device to a replicate device, providing and maintaining close contact between the master device and the replicate device poses certain problems. These problems become even more acute if the surfaces to be contacted are of large area. In accordance with the present invention, close contact over even large areas is obtained between a master device and a replicate device by forming a thin and uniform liquid layer between the master and replicate devices, thus producing a vacuum effect which serves to tightly press the master and replicate devices together.