Abstract: A transcoding arrangement transcodes television signals sampled at a first clock rate into second signals sampled at a second clock rate. An integer number of samples of the television signals are assembled into blocks, each block containing an integer number of samples of the second signal. The integers are selected to reduce the number of multipliers required to perform the transcoding. A delay element forms four successive delayed samples of the incoming television signal. The first and last delayed samples are summed and then multiplied by a running variable multiplicand to form a weighted sum signal. The second and third delayed samples are multiplied by respective running variable multiplicands to form second and third weighted delayed samples. The weighted second and third samples are summed to form a sum which is subtracted from the weighted sum signal to form the interpolated output sample.

Abstract: An electromechanical cutting stylus is used in a system for mastering video disc recordings in a metal substrate. The cutting stylus introduces signal distortions and errors into the mastering process such that the quality of the reproduced signal displayed on a television receiver is affected. A non-linear optical system, i.e., a Michelson interferometer, is incorporated to measure the non-linearities introduced by the recording process. The non-linear effects of the optical measuring system may be eliminated or reduced by choosing cardinal operating points for measuring the recording non-linearities.

Abstract: A surface acoustic wave record stylus is constructed from a support having a surface for propagating surface acoustic waves. A circular-shaped interdigital transducer launches the surface acoustic waves onto the support surface. The shape of the interdigital transducer is such that the surface acoustic waves are focused to a diamond stylus positioned at the center of the circular transducer.

Abstract: A stylus, having a conductive electrode, is arranged to follow a spiral groove on a disc in a video disc player. Video and audio information are recorded in the bottom of the groove as relief variations. When relative motion is established between the stylus and the groove, the spacing between the stylus electrode and relief variations provide capacitance variations representative of the recorded video and audio. A dual-gate field-effect transistor is used in a pickup circuit to detect signals related to these capacitance variations. One gate of the transistor is coupled to the stylus electrode to detect capacitance variations while the other gate is coupled to a local oscillator to modulate the detected capacitance variations.

Abstract: A high-definition television system for electronic cinematography includes vertical scanning for ease of line-rate transcoding or adaptation to standard-definition television systems. The number of vertical line-scans is selected for transcoding to a standard-definition system by deleting alternate vertical line-scan samples.

Abstract: A Dove prism is provided in a multiple beam optical disc record and playback system. In a multi-track optical system, the multiple spots formed in a multi-channel modulator are imaged on the record medium. The track-to-track spacing between adjacent tracks may be adjusted by rotating the Dove prism such that the angle formed between a line which passes through the center of the spots and the velocity vector of the disc is varied.

Abstract: A multi-electrode array deposited on a piezoelectric substrate is driven by a traveling-wave voltage generated from a wave delay generating device, such as a tapped coaxial cable. Suitably delayed and phased voltages are fed to each electrode in the array. Surface acoustic waves are excited on the surface of the piezoelectric substrate. The surface acoustic waves travel through the array in proper phase with the exciting signal supplied to the electrodes. The surface acoustic waves pick up energy as they travel along the surface. Such a structure has a number of advantages over the prior art conventional interdigital transducers. For example, they exhibit broad bandwidth characteristics, have high conversion efficiency and are generally free of spurious signals. These advantages make them well suited for application to video disc cutterheads.

Abstract: A cutting stylus is positioned with respect to a metal substrate in order to cut a groove. The cutting stylus is vibrated about a quiescent position in response to a relatively high frequency signal while cutting the groove in order to cut an information track comprising short wavelength modulation of the groove depth. Relative motion is established between the metal substrate and the cutting stylus such that the information track is cut along a spiral path. The relative motion is varied in a predetermined manner as the stylus cuts across the surface of the metal substrate such that the spiral information track is formed having a varying pitch to reduce the formation of damaging ridges on the cutting edge of the stylus.

Abstract: A cutting stylus adapted for mechanically cutting a deep groove, which may be used in lapping the keel on a playback stylus, is provided. The stylus includes a tapering body, a constricted terminal region and shoulders joining the tapering body and the constricted terminal region. The shape of the constricted terminal region is complementary to the shape of the keel tip on the playback stylus. The terminating portion of the stylus tip has a substantially flat cutting face, a pair of side surfaces extending from the side cutting edges of the cutting face which taper at a slight angle to provide clearance to the side cutting edges, and a bottom surface extending from the bottom cutting edge of the cutting face at an angle which provides relief to the bottom cutting edge.

Abstract: A measuring gauge, suitable for measuring the plastic record caddy for a video disc, uses a transducer and a driver assembly. The transducer includes a plunger which will trigger a detector if a force of less than one gram is applied thereto. The transducer is coupled to the driver assembly. The driver assembly includes a stepping motor for moving the transducer and a target and sensor for providing an indication of a reference position.

Abstract: A turntable drive system for use with a video disc player employs a low cost magnetic sensor, such as a Hall effect device, for turntable speed control. An integral motor mounting bracket and flux concentrator is positioned with respect to a ring magnet having a plurality of permanently magnetized poles of alternate polarity along its periphery such that the magnetic field of the magnetized ring passes through an active surface of the magnetic sensor. The Hall effect device provides an output representative of the rotary motion of the ring magnet which is fixed to the turntable. The output of the Hall effect device is compared to a reference oscillator and an error signal indicative of drift in the rotary speed of turntable from the predetermined speed is fed to a DC motor for driving the turntable at the desired rotational speed.

Abstract: A gimballed air puck is used in a video disc mastering system for controlling the depth to which an electromechanical stylus cuts into a metal substrate surface. Air is directed through the air puck toward the substrate surface to maintain the cutting stylus at a given cutting depth. The air puck is gimballed or swivelled to permit the cutting stylus to follow the undulating surface of the substrate during the mastering operation.

Abstract: A flaw detection system optically detects defects on the surface of a grooved video disc surface. A beam of light incident on the surface being inspected is reflected thereby into a series of diffraction order cones. A cylindrical lens converges the higher diffraction order cones onto a split photodetector. When the light beam which scans the disc surface passes over a surface defect, such as a hillock, the reflected beam is deflected first to one photosensitive surface of the split photodetector and then to the other, thus providing an output from the photodetector to indicate the presence of such a defect.

Abstract: Recovery from a record of data recorded in an information track, comprising depressed areas of a given width, a given depth, and variable length, alternating along the length of the track with relatively non-depressed areas, is effected by an optical playback system. The playback system employs means for focusing light from a laser source on the information track as a light spot having a diameter which is diffraction limited. The focusing system includes an independent light source (e.g., laser) which impinges on the surface of the record as a circular spot which illuminates a plurality of elongated tracks. The circular spot is imaged by a lens system on to a detector plane which is positioned at a plane which is conjugate to the record surface.

Abstract: Recovery from a record of data recorded in an elongated information track, comprising depressed areas of a given width, a given depth and variable length, alternating along the length of the track with relatively non-depressed areas, is effected by an optical playback system. The playback system employs means for focusing light from a laser source on the information track as a light spot having a diameter which is diffraction limited. The focusing system includes an additional light source (e.g., laser) which impinges on the surface of the record as a circular spot which illuminates a plurality of elongated tracks. The circular spot is imaged by a lens system on a detector plane which is positioned at a plane which is conjugate to the record surface.

Abstract: Recovery from a record of data recorded in an elongated information track, comprising undulations representative of the data is effected by an optical playback system. In the system, the data is recorded within two substantially different frequency bands. The optical playback system has a dual response characteristic to provide improved response at the two different frequency bands. A modifying means interposed in the light beam path shapes the light beam to effect this dual response characteristic (i.e., two different bandwidth responses).

Abstract: A keel-tipped stylus for playback of video information from a disc record comprises a tapering body, a constricted terminal region and shoulders joining the tapering body to the constricted terminal region. A method for preparing a deep groove plastic replica disc for use in lapping the constricted terminal region on the tip of the playback stylus is disclosed. The method includes the step of mechanically cutting a deep groove into a metal substrate surface with a diamond cutting stylus. The diamond cutting stylus has a tip having a shape complementary to the shape of the keel groove to be formed into the metal surface. During the mechanical cutting operation, the tip of the stylus is introduced into the metal surface to a depth sufficient to cut the deep groove to the desired depth across the surface of the metal substrate.

Abstract: Apparatus for orienting a cutting stylus having a mounting face and a cutting face includes a base member having a flat, nonadhesive surface and a stylus holding fixture. The stylus holding fixture includes a mounting block having a surface vertical to the flat, nonadhesive surface of the base member. The cutting stylus is attached with epoxy to the vertical surface of the mounting block which forms the proper angle to orient the cutting face of the stylus for subsequent lapping on a lapping machine. A capping plate having a recess for the cutting stylus is attached to the mounting face of the mounting block. With the stylus mounted in the mounting block the stylus holding fixture may now be placed on a lapping machine for the stylus lapping process.

Abstract: Eccentricity control apparatus is provided in a system for optically recording and reading information on a rotating disc medium. The information may be recorded on concentric or spiral tracks. The eccentricity control apparatus includes a detector for detecting track crossings as an optical scanning head scans the disc surface. The detector provides pulses representative of track crossings. The number of pulses in a once-around is representative of the amplitude of an eccentricity control signal. The angle measured between a once-around pulse and a minimum pulse rate of the track crossings indicates the phase of the error. An eccentricity error signal which is generated by suitable circuitry is applied to affect the manner in which the optical scanning head scans the disc surface such that number of track crossings is reduced.

Abstract: Apparatus provides an incident light beam which illuminates the surface of a grooved disc, having signal elements recorded therein in the form of a succession of spaced apart depressions, with a light spot that spans a plurality of convolutions of the groove. The structure of the groove convolutions and signal elements forms a two-dimensional diffraction grating which reflects light into a plurality of diffraction order beams. Photodetectors, respectively positioned to intercept several of the reflected beams provide outputs corresponding to the light power in the respective reflected beams. Estimations of signal element depth in the region illuminated by the light spot may be made from the measured light powers.