Abstract: Apparatus for reproducing coded audio signals includes interpolation circuitry for substituting interpolated signal values for erred or lost audio signal. To minimize undesirable audible artifacts which may be introduced into the audio signal by virtue of the substitution process, the rate of substitution is monitored. When the rate of substitution exceeds a predetermined rate, the higher frequency components of the audio signal, including the substituted values, are attenuated.

Abstract: A process of image signal coding provides motion vectors for blocks of picture elements (pixels). An array of motion vectors for pixel blocks may be used to generate a zoom and pan vector for a full image. When the format of a vertically subsampled image is changed before coding, motion parameters for a full image are used to obtain maximum local resolution after subsampling. Remaining image areas which have not been fully motion compensated are detected by an alteration (change) detector and are vertically filtered in a field.

Abstract: A disc playback apparatus includes a system for scanning a disc and storing in memory, an address associated with every point on the disc where the scanning device mistracks. A modified regulating signal is calculated for guiding the scanning device back onto the desired data track, from the value of the regulating signal generated by the tracking regulation circuit prior to track loss. The modified regulating signal is also stored in the memory, and during every subsequent reading of the disc, upon encountering track areas associated with stored addresses, the tracking regulation circuit is provided a corresponding modified regulating signal in order to maintain the scanning device near the desired data track. In further scans of the disc successive modified track regulating signals are iteratively generated and tested for tracking response until a substantially optimum modified signal is generated.

Abstract: Apparatus and a method for formatting executable codes and data, defining interactive applications, with video and audio program material, for reliable and convenient access includes compressing (18, 21) audio and video programs according to a protocol such as MPEG. The compressed audio and video (A/V) programs are formed (19, 22) into transport packets. Interactive application programs associated with A/V programs are compiled (10) into functional modules, condensed and formed into transport packets. A module may be executable software or data. Further modules designated "Signal modules", are generated to condition respective receivers to suspend or resume execution of an interactive application. Video packets, audio packets and application packets are time division multiplexed (16) for transmission. Signal modules are multiplexed in the packet stream to appropriately reprogram respective receivers on the occurrence of such changes in received signal components.

Abstract: An antenna system capable of receiving electromagnetic radiation having either right or left helical polarization, and either vertical or horizontal linear polarization includes an energy concentrator which concentrates energy at a focal point. A helical antenna is arranged in the proximity of the focal point. A first switch switches the helical antenna to a backfire mode of operation and a second switch switches the helical antenna to an end fire mode of operation. A control mechanism controls the switches to select the nature of the polarization.

Abstract: Items of auxiliary information are transmitted in an AM radio broadcast signal by phase angle modulating the AM carrier with digitally encoded data representing the auxiliary information. The items of auxiliary information are allocated to a cyclically recurring number of groups, each group consists of two equal length information blocks. Each information block includes an information word and a check word. Different offset words are superimposed on the respective ones of the check words. The offset words are useful for the synchronization of the information blocks in a receiver.

Abstract: A video signal compression system includes motion compensated predictive compression apparatus for compressing respective frames of video signal according to either intraframe processing or interframe processing on a block by block basis to generate blocks of compressed data and associated motion vectors. A compressed signal formatter arranges the blocks of compressed data and the associated motion vectors according to a desired signal protocol wherein motion vectors of interframe processed frames are associated with corresponding blocks of compressed data and motion vectors of intraframe processed frames are associated with blocks substantially adjacent to corresponding blocks of compressed data. The motion vectors are included with intraframe compressed data to facilitate error concealment at respective receiver apparatus.

Abstract: A more accurate voltage-to-time and then time-to-voltage conversion is accomplished by tailoring the amplitude versus time characteristics of the pulses generated in the voltage-to-time conversion. One embodiment includes applying a ramped voltage supply to an amplifier coupled between the voltage/time converter and the time/voltage converter. The ramped supply is arranged to condition the amplitude of a portion of respective pulses to include a slope similar to the ramped voltage applied to the time/voltage converter. This tends to effect a more accurate response in the time/voltage converter.

Abstract: A system is disclosed for the compatible transmission of a 16:9 progressive scan television signal by means of a letterbox formatted line interlaced signal. The letterbox edge bands contain a vertical helper signal representing the difference between a predicted progressive line and adjacent interlaced lines. Improved resolution of a progressive image at a progressive 16:9 receiver is facilitated by specially arranged half band filters in the transmitter/coder and inverse half band filtering in the receiver. Alternatively, when ordinary low pass filtering is used in the coder prior to interlaced subsampling, the fidelity of a reproduced image is improved using, an approximate simulation of such coder low pass filtering in the decoder together with a correction signal derived therefrom. An image reproduced at the progressive 16:9 receiver can more closely resemble the transmitter source signal by interative processing of the receiver correction signal.

Abstract: A receiver (FIG. 2 ) for decoding associated compressed video and audio information components transmitted in mutually exclusive "frames" of data with respective time stamps PTS.sub.vid and PTS.sub.aud respectively, includes a controller (216) which is responsive to the respective received time stamps to provide coarse synchronization by delaying or skipping respective frames of one or the other of the components to approximately time align the two components. Fine synchronization is provided by adjusting the processing or clock frequency (215) of the audio signal processor (212) independent of the video processor (214). The control for the frequency adjustment is related to the difference between audio and video time stamps.

Abstract: Video signal compression apparatus includes a memory for storing two fields of image data and providing fields of image data separated by one frame intervals. Image data from corresponding fields of successive frames are subtracted to generate field differences. The field differences are accumulated over respective field intervals, and the sum is compared against a predetermined value. If a sum of differences over a field is less than the predetermined value, the most recent field is considered to be redundant and may be excised. After respective fields are excised, frames of video signal are composed from the remaining fields. The field types (e.g., odd or even) of the fields in the memory are determined, and the data is accessed from the respective fields in memory such that data from odd and even fields occupy odd and even lines in the composed frames respectively.

Abstract: A rate controlled VBR quantizing system includes a quantizer for quantizing partially compressed video data and further apparatus for monitoring the amount of compressed output data. Dependent upon the amount of compressed output data being lesser or greater than a predetermined value, the quantizer is conditioned to operate in a fixed quantization mode, or a mode wherein only selected blocks of data in respective frames are adaptively quantized, respectively.

Abstract: The relationship of a reference current of a current balancing circuit to a first output current at the collector of an output transistor is adjusted via the dimensioning of a first resistance R in the emitter of the output transistor of a current balancing circuit. By adding a second current balancing circuit with a second resistor R' contained therein and which provides a second output current, there results, for R=R', the relationship of the first output current to the second output current corresponding to the relationship of the reference current to the first output current.

Abstract: A hybrid Discrete Cosine Transform (DCT) coder processes blocks of (e.g., 8.times.8) pixels from interlaced or progressive scanned image signals. Processing of image lines by the coder is modified in the presence of image motion to avoid switching between 8.times.8 and 2.times.(4.times.8) transformations. For motion, the lines of two vertically superimposed image blocks are rearranged to produce first and second modified blocks. The modified first block contains pixels from lines in a first field, and the modified second block contains pixels from lines in an associated adjacent second field.

Abstract: In a multi-winding motor of the type which develops switching spikes from respective drive signals, separate interference suppression apparatus is not provided for each motor winding to be triggered, but rather interference suppression circuitry is shared between respective winding drive signal paths. In a first arrangement, a single resistor-capacitor impulse suppression network is commutated between all motor winding connections in predetermined phase relation with the application of drive currents to the respective windings. In a further arrangement, a single impulse suppression circuit is used to cyclically couple the respective low power motor trigger signals to the respective high power winding drive amplifies, which suppression circuit precludes the generation of interference pulses at the interface between the drive circuitry and the motor to be driven.

Abstract: A clocked digital signal processing system includes apparatus for unambiguously indicating the phase of an input signal relative to a reference clock signal. In particular, the disclosed apparatus reduces timing uncertainty between the reference clock, and the output signal of a phase detector representing the phase relationship between the input signal and the reference clock. A phase detector including a logic network provides plural comparison signals representing a phase relationship between the input and reference signals. The comparison signals are conveyed via first and second latch circuits, in respective groups, to a clocked downstream stage. The first and second latch circuits are clocked by different phases of the reference clock and provide outputs synchronous with the reference clock. The downstream stage responds to the reference clock for conveying output signals front the first and second latch circuits to an output at which the unambiguous indication appears.

Abstract: A block of picture elements is DCT transformed and coded to produce a corresponding data block of variable length codewords having an average length. The data blocks are apportioned among fixed length transport blocks as needed to produce full transport blocks. The transport blocks include a direct (DC) component and alternating components at prescribed locations, as well as an address information flag indicating whether or not block data is longer or shorter than the average length, and an address pointer, to facilitate recovery and synchronization of apportioned data blocks at a decoder.

Abstract: Variable length codewords representing high definition television image information are processed by a codeword analyzr for prioritizing codewords within a predetermined codeword group. A single FIFO rate buffer conveys codewords subject to analysis to the analyzer. A succeeding codeword group is written into the buffer when a current codeword group is being analyzed, at which time buffer read out is inhibited. In an illustrated embodiment, buffer read out is inhibited, and codeword analysis begins, when MPEG Picture Start or Slice Start codewords associated with the succeeding codeword group approach the buffer output. Buffer read out is enabled at the end of the analysis interval.

Abstract: A select line scanner for a liquid crystal display includes a plurality of cascaded stages each having an input terminal and an output terminal. Each stage includes a push-pull output circuit including pull up and pull down transistors driven with separate control signals. A further transistor has its conduction path coupled between the control electrode and a point of potential of sufficient value to turn the pull up transistor off. The control electrode of the further transistor is coupled to an output of a succeeding one of the cascaded stages to insure that the output of the respective stage cannot drift to an on state.

Abstract: A compression/decompression system includes a source of (1:1 60 Hz) non-interlaced scanned video signal. A preprocessor constructs (2:1 60 Hz) interlaced scanned video signal from the non-interlaced scanned video signal by selection of alternate lines of successive non-interlaced image signals. The interlaced scanned video signal is compressed according to an MPEG protocol of I, P and B frame compression algorithms. I, P and B frame compression is performed such that there are an odd number, greater than one, of B-frames between successive I/P frames (for example the sequence of compressed frames may conform to I, B1, B2, B3, P, B1, B2, B3, P, B1, B2, B3, I, B1, . . . etc). The I compressed frames, the P compressed frames and alternate B compressed frames (the frames B2 in the exemplary sequence) selectively form a primary compressed (2:1 30 Hz) interlaced video signal for reproduction by interlaced scanned receivers. The intervening B-frames selectively form a secondary compressed video.