Abstract: The gain of an input video signal of different possible gains relative to a selected reference gain is adjusted according to an associated key signal indicative of gain change previously undergone by the input video signal and an independent key signal indicative of the desired change in gain to produce an output video signal having a selected gain determined by the values of the associated and independent key signals. The output video signal is combined with other video signals, whose gain may or may not have been adjusted relative to the reference gain.

Abstract: A multi-standard color field sequence detector includes an analog and a digital processor section, wherein the analog processor section receives a reference video input and provides the signals necessary to drive the digital processor section. A correlator control circuit counts an exact number of 13.5 MHz reference clock cycles, and then supplies a start signal to a burst correlator circuit, which takes samples of a plurality of cycles of burst and correlates the results to determine the polarity of the burst samples. If they are of a first polarity, a count value of corresponding polarity is supplied. If they are of the opposite polarity, a count value of the corresponding opposite polarity is supplied. The sequence of the polarities of the final counts are detected to identify the color field 1 for the standard being used.

Abstract: A protective or purge enclosure provides a positive atmosphere around an operating device such as a hand-held computer or calculator contained therein. The protective enclosure has sufficient flexibility, even though providing a positive, sealed atmosphere, to enable the user to operate the functional features of the device sealed within the enclosure, and the material forming the device is sufficiently transparent to enable the user to view the functional features of the device for operation. A visible indicator provided on the enclosure enables the user to determine if the enclosure is maintaining the positive atmosphere sealed therein.

Abstract: The data packer receives n-bit wide parallel data words, and it outputs m-bit wide packed parallel data words, where n is a variable and may change during the operation, and m is a fixed integer. The input data words are applied to a bit shifter and therefrom to a data output circuit where they are stored until the necessary m bits are obtained. In the preferred embodiment a control circuit which comprises an adder, receives information indicating the number of valid data bits in each input word, and it provides a running sum of the number of received valid data bits. When the number of bits in an input word is equal to or greater than m, the control circuit provides a first control signal which occurs simultaneously with an m-bit wide packed parallel output word provided by the output circuit. Any number of input bits which is less than m is added to a remainder of a previous sum which is also less than m.

Abstract: A cassette storage basket configured for mounting on a rack mounted storage system. A wire-form basket includes an open front defined by a rectangular frame, with the frame rearwardly tilted to give the basket a triangular profile. A rear wall of the basket incorporates at least one upper hook and a rearwardly extending lower abutment to tilt the bottom of the rack-mounted basket from the horizontal to protect cassettes stored in the basket during transport.

Abstract: A highly reliable shadow memory system is able to survive multiple fast sequence power failures and includes a volatile main memory and a shadow memory subsystem which continually monitors write accesses to the main memory. The shadow memory subsystem includes a disk drive or shadow memory storing a copy of the data in main memory. As the main memory contents are altered, the shadow memory is continually updated to reflect the changes while main utility power is available. In the event of a main utility power failure, backup power is required to store main memory data in the shadow memory for only a few storage locations for which the updating of the shadow memory may lag main memory data changes. Consequently, only a small portion of available battery backup power is required to preserve all main memory data and the system can withstand multiple rapid succession power failures without loss of data.

Abstract: A TV video signal synchronization signal system enables a video device such as a digital special effects system to operate synchronously in response to an input video signal and still produce an output video signal synchronized to a television studio locking reference signal. The video device and the synchronization signal generating subsystem thereof operate in response to a pixel rate clock of approximately 70 ns and in response to a phase command to generate timing for the horizontal sync pulse, color burst signal and video data of the output video signal. The output color burst signal remains phase locked to the locking reference signal with output gating being responsive to the phase command. A ROM interpolator provides subpixel accuracy for the output horizontal sync pulse while output line buffering and interpolation permits the output video data to the phase matched to the reference master sync signal.

Abstract: A storage container is of a configuration and dimensioned to retain either two DAT cassettes, two storage cases or one cassette together with one storage case. The size of the DAT cassette storage container is comparable in size and shape to a Beta video cassette storage case. The storage container has an interior structure that forms a pair of seats, each having two distinct parts. A first of the two parts is of a configuration for receiving and retaining the protective storage case for DAT cassettes. A second of the two parts is of a configuration for receiving the DAT cassette itself and retaining it within the container. The storage case and cassette are retained within the container with their length dimensions orthogonal.

Abstract: A method and apparatus detects synchronizing sequences in a digital data stream. The apparatus comprises a plurality of candidate sequence generators and associated vote counters which are used in conjunction with comparators to test the order of received synchronizing symbols of a predefined sequence of predefined symbols against a plurality of corresponding candidate symbols of candidate sequences. A candidate generators begins a new candidate sequence when an ambiguity in the input symbol sequence is detected, i.e., when a received symbol does not match a candidate symbol of one of the previous candidate sequences. The apparatus includes a voter decision logic circuit which selects a winner among the candidates based upon the number of votes or matches tallied for each candidate sequence.

Abstract: A dynamic head position tracking control for a magnetic tape playback system employs a detected dither signal to determine the elevational position of a pair of magnetic transducing heads relative to tracks of recorded information being scanned by the heads. This detection is carried out at several locations along the lengths of the tracks being scanned, and a value is stored for each of the locations. Based upon the stored information, an estimation is made of a position value for the first location along the length of the tracks. This estimation is determined from a weighted extrapolation of the following two samples taken during the scan of the track. The elevational position of the heads is then dynamically controlled in accordance with the actual and estimated head position values.

Abstract: Plural magnetic transducing heads are employed to record and reproduce video information that is stored in a segmented format. One head is in contact with the magnetic recording tape while the other head is out of contact with it. The position of the head which is in contact with the tape is controlled by a suitable ramp voltage generated in accordance with the ratio of actual tape speed to normal play speed, to maintain the head generally aligned with a track on the tape. The other head, which is out of contact with the tape, is also positioned in the same fashion. When a repositioning of the heads is required, a determination is made whether the track of information being reproduced by the head in contact with the tape relates to a particular segment of a field, for example the last field.

Abstract: A system for controlling a pulse-driven dc motor includes a pulsed grounding switch, an inductor connected between the pulsed grounding switch and the armature of the dc motor, and a tracking circuit connected across the inductor. The control system further includes a variable resistor that provides a series path through the inductor for dissipating generated armature current from the motor. In operation, the resistance provided by the variable resistor depends upon the counter emf generated by the motor and upon transient voltages induced across the inductor when the pulsed grounding switch is periodically opened and closed. More particularly, the variable resistor provides minimal resistance when the back emf of the motor is low and provides increasing resistance as the back emf of the motor increases.

Abstract: A technique for recovering helical audio using the standard synchronous reference clock of the video tape recorder system to conventionally clock the transport and the video signal processor, including the video timebase corrector. A modified audio signal processor clock is generated which is varied commensurate with the desired rate of tape speed override, varying accordingly the flow of audio data through an audio timebase recorder. The speed of a helical scanner is varied in accordance with the rate of tape speed override, to lock the scanner angular position to the audio timebase corrector. In turn, a capstan servo adjusts the tape position in respsonse to the scanner angular position to lock the tape to the scanner. Meanwhile, the video signal processing proceeds conventionally by skipping or repeating fields or frames via a frame store to match the rate of tape speed override.

Abstract: A mounting assembly is provided for supporting an elongated flexible member, such as an electrical signal cable, connected between relatively movable termination points, for example, between a stationary frame and a mobile carriage. The mounting assembly comprises one or more track units each including a guide channel having one side opening toward an adjacent, generally parallel roller-supported belt. The flexible member is anchored at a first termination point generally at a longitudinally centered position within the channel and extends along the channel before rolling back upon itself through a turn of 180 degrees to contact the belt, with the channel-belt spacing being less than twice a natural radius of curvature for the flexible member whereby the belt applies a force against the flexible member in the region of the turn. The flexible member extends from the curved loop along the belt and is secured thereto at a second termination point.

Abstract: A composite door assembly for a magnetic tape cassette includes a hinge pin having a first torsion spring element at one end encapsulated in the molded door, a second torsion spring element disposed at an opposite end of the pin for mounting on the cassette, with the opposite ends of the hinge pin secured to the cassette to mount the door on the cassette, and with the first and second torsion spring elements biased to maintain the door in a closed position.

Abstract: A tape transport capable of receiving cassettes of varying sizes, one at the time for play, includes a cassette indexing mechanism capable of selectively positioning the spindles which engage the reels of an associated cassette at a selected distance corresponding to the reel-center-to-reel-center distance of the cassette. Mis-insertion apparatus associated with the transport provides that any cassette smaller than the cassette receiving opening in the transport will be protected against being improperly inserted into the transport.

Abstract: A closure device for a library storage box combines a hanger with a locking device for the closed storage box. A hinge structure for the device provides a first hinge portion on the box, connected by a flexible hinge to a second hinge carrying the hanger at its outer end. A latch on the second hinge portion engages a complementary detent on the first hinge portion to hold the box closed and to project the hanger to an engaging position for mounting on a suitable rail.

Abstract: A method and apparatus for producing special motion effects such as slow or fast motion, still frame and other effects from video magnetic tape is disclosed which is particularly applicable to helical wrap recording and reproducing apparatus. The apparatus employs a transducing head that is mounted on a revolving scanning drum, with the head being movable in a line generally transverse to the recorded track. The present invention utilizes the transverse positioning of the head to accurately follow a track during reproducing or playback and, at the completion of the track, to properly position or set the head in position to either play the next adjacent successive track, replay the same track, or play yet another track so that special motion effects can be achieved without experiencing picture breakup or unwanted noise.

Abstract: A method and system for encoding color frame polarity information into composite sync signals. Also, a method and system for detecting color frame polarity information which has been encoded into composite sync signals and for restoring the encoded composite sync into its normal non-encoded form.