Abstract: An apparatus for optically reading or recording information on an optical disc which is rotatable about an axis of rotation. The apparatus includes a frame, a carriage, a carriage drive, an objective lens, an objective lens holder, a focus drive and a fine tracking drive. The objective lens is mounted on the objective lens holder so that the optical axis of the objective lens substantially intersects the center of mass of the carriage. The fine motor, used for tracking and focus, has a center of mass that substantially lies on the optical axis and proximate the center of mass of the carriage.

Abstract: A pick-up device for optical recording and playback includes two linear actuators coupled to an optical module and lying in a plane normal to the surface of an optical recording medium. The actuators are obliquely inclined to the optical axis of the optical module. Proportional differential actuation of the linear actuators moves the optical module bi-axially, i.e., normal or parallel to the recording medium surface, permitting control of both focus and tracking of information bits on the surface. The preferred embodiment employs two bi-directional linear actuators, each comprising a pair of back-to-back uni-directional actuators, each of which includes a flexible tubular housing enclosing a stack of thin, perforated disc-shaped electrodes separated by a dielectric fluid. Conductive elastomeric spacer rods support the disks in a parallel, longitudinally, spaced apart arrangement.

Abstract: The invention discloses a method and an apparatus for implementing an L phase clock in conjuction with L counters, where L is an integer, to count at a frequency scalable by L.

Abstract: A pick-up device for optical recording and playback includes two linear actuators coupled to an optical module and lying in a plane normal to the surface of an optical recording medium. The actuators are obliquely inclined to the optical axis of the optical module. Proportional differential actuation of the linear actuators moves the optical module bi-axially, i.e., normal or parallel to the recording medium surface, permitting control of both focus and tracking of information bits on the surface. The preferred embodiment employs two bi-directional linear actuators, each comprising a pair of back-to-back uni-directional actuators, each of which includes a flexible tubular housing enclosing a stack of thin, perforated disc-shaped electrodes separated by a dielectric fluid. Conductive elastomeric spacer rods support the disks in a parallel, longitudinally, spaced apart arrangement.

Abstract: An improved system for recording and playing back digital information in a special pulse-length modulation format on a disc-shaped record. The digital information is stored in a succession of alternating marks and spaces, both having lengths that are discretely variable in accordance with a succession of multi-bit binary code blocks.

Abstract: An IDCT, or Inverse Discrete Cosine Transform, method decimates a 2-D IDCT into two 1-D IDCT operations and then operates separately on the even and odd pixel input words. In a common processing step, selected input values are passed directly to output adders and subtractors, while others are multiplied by constant, scaled cosine values. In a pre-common processing step, the lowest-order odd input word is pre-multiplied by .sqroot.2, and the odd input words are summed pairwise before processing in a common processing step. In a post-common processing step, intermediate values corresponding to the processed odd input words are multiplied by predetermined coefficients to form odd resultant values. After calculation of the even and odd resultant values, the high-order and low-order outputs are formed by simple subtraction/addition, respectively, of the odd resultant values from/with the even resultant values. The input values are preferably scaled upward by a factor of .sqroot.2.

Abstract: An improved system for recording and playing back digital information in a special pulse-length modulation format on a disc-shaped record. The digital information is stored in a succession of alternating marks and spaces, both having lengths that are discretely variable in accordance with a succession of multi-bit binary code blocks.

Abstract: A programmable logic output driver includes a bias generator (100), a current mirror (200) and an output stage (300), there being a digital programming feature to maintain the output voltage slew rate at an acceptable value for either high or low values of load capacitances. The driver is programmable and can maintain a constant value of driver output resistance in the circumstances where the load voltage approaches the full swing logic voltage. In the preferred embodiment, the programmed output resistance is independent of variations in process, temperature and VDD supply voltage. TTL loads are driven with the minimum amount of required output current. Because of the constant resistance, the driver supplies a specified amount of current to the load even when the load is pulled down to a specified voltage.

Abstract: An improved system for recording and playing back digital information in a special pulse-length modulation format on a disc-shaped record. The digital information is stored in a succession of alternating marks and spaces, both having lengths that are discretely variable in accordance with a succession of multi-bit binary code blocks.

Abstract: An improved system for recording and playing back digital information in a special pulse-length modulation format on a disc-shaped record. The digital information is stored in a succession of alternating marks and spaces, both having lengths that are discretely variable in accordance with a succession of multi-bit binary code blocks.

Abstract: An improved system for recording and playing back digital information in a special pulse-length modulation format on a disc-shaped record. The digital information is stored in a succession of alternating marks and spaces, both having lengths that are discretely variable in accordance with a succession of multi-bit binary code blocks.

Abstract: An improved system for recording and playing back digital information in a special pulse-length modulation format on a disc-shaped record. The digital information is stored in a succession of alternating marks and spaces, both having lengths that are discretely variable in accordance with a succession of multi-bit binary code blocks.

Abstract: An improved system for recording and playing back digital information in a special pulse-length modulation format on a disc-shaped record. The digital information is stored in a succession of alternating marks and spaces, both having lengths that are discretely variable in accordance with a succession of multi-bit binary code blocks.

Abstract: A video record medium, such as a record disc, for recording a composite video and audio signal suitable for stop-motion playback, with accompanying audio. Discrete segments of an analog audio signal are digitized and compressed in time and recorded on alternate tracks on the disc, and corresponding frames of a video signal are recorded on the tracks located therebetween. During playback of the disc, a selected audio track is scanned initially and the digital audio data recovered therefrom is entered into a memory device, after which the track for recording the corresponding video frame is scanned in a repeated fashion, to produce a stop-motion display of the frame, while the stored audio data is extracted from the memory device and converted back to an analog format, for simultaneous playback at its original speed.

Abstract: Method for evaluating the quality of audio and/or video transfer characteristics of a device upon which, or through which, audio and/or video information is contained, or passes, respectively. The method concerns the evaluation of the quality of information transfer in the recording and playback of a recording medium or in the transferring of audio and/or video information through an information handling device referred to as a throughput device. Unit evaluation includes establishing an input signal of known content, measuring selected parameters of selected parts of the input signal, feeding the input signal to the unit under test, measuring the parameters of parts of the output signal from the unit corresponding to the same selected parts of the input signal, and comparing the selected parameters of the input signal with the corresponding parameters of the output signal.

Abstract: An improved system for recording and playing back digital information in a special pulse-length modulation format on a disc-shaped record. The digital information is stored in a succession of alternating marks and spaces, both having lengths that are discretely variable in accordance with a succession of multi-bit binary code blocks.

Abstract: A record disc for storing a composite signal that includes segments of audio information and corresponding segments of video information. The disc contains a succession of consecutively arranged substantially circular and concentrical information tracks including audio information-containing tracks and separate video information-containing tracks. Each of the audio information-containing tracks has at least a portion of an audio information segment stored therein in time-compressed digital data format, and each of the audio information segments includes packets of digital data interleaved with conventional video synchronizing signals, with adjacent audio information packets representing a continuous portion of the stored audio information segment. Each of the video information-containing tracks has a video information segment stored therein in real time, and each video information segment contains a single video frame in conventional video format including conventional video synchonizing signals.

Abstract: An improved system for recording and playing back digital information in a special pulse-length modulation format on a disc-shaped record. The digital information is stored in a succession of alternating marks and spaces, both having lengths that are discretely variable in accordance with a succession of multi-bit binary code blocks.

Abstract: A series of separate analog electrical signals are received at a real time rate and converted to digital equivalents. The converted signals are stored in a digital memory from which the signals are released serially at a rate slower than the real time rate at which the signals are received. The signals released from storage are directed to a signal analyzer, preferably after being converted from digital to analog format, for processing to determine prescribed parameters of the original analog electrical signals.

Abstract: A method and apparatus for recording a data signal on a light-reflective record disc, wherein an intensity-modulated write beam of light is focused onto the disc as the disc is rotated in a prescribed fashion, to produce a sequence of spaced non-reflective regions representative of the data signal. Additionally, a relatively low intensity pre-write beam of light scans the disc in advance of, but synchronous with, the write beam to detect the presence of nonreflective defects in the disc that could inhibit the recording of the data signal thereon. Whenever such a defect is detected, a special defect flag code is recorded in advance of and over the defective region, whereby when the data signal is recovered from the disc at a subsequent time, it can be recognized that the data signal is being temporarily interrupted.