Abstract: A distributed computer system is disclosed which includes a central location and a plurality of remote locations. A central location computer system generates a module which includes a data section containing a plurality of data units. Each of the data units is either a minimum addressable data unit or a longer data unit. Each longer data unit contains a plurality of minimum addressable data units. The module also includes a swap section containing data identifying locations of longer data units within the data section. A remote location computer system receives a module, and contains a loader. The loader swaps the minimum addressable data units of the longer data units in the data section. A transmission link, transmits the module from the central location computer system to the remote location computer system.

Abstract: A sparse digital adaptive equalizer including forward and feedback Finite Impulse Response (FIR) filters exhibits improved Least Mean Square operation. A switch assigns one of several multipliers of each filter to any one of the tap locations of that filter. Each multiplier is initially assigned to a preselected tap location with a predetermined weighting coefficient. After completing successive time cycles having a duration equal to a given number of data sample periods, for each filter there is determined (a) a first group of coefficients associated with multipliers then assigned to non-zero value tap locations, and (b) a second group of coefficients associated with multipliers then assigned to zero valued locations. Multipliers associated with first group coefficients during a just-completed time cycle retain their tap locations during the next time cycle.

Abstract: A higher order phase loop filter includes an integrator consisting of an adder (25) and a delay element (31) arranged in a feedback loop between the output port of such adder and one of its input ports. Signal to be filtered is applied to a second input port of the adder. A detector (30) is coupled to the output of the adder to detect limiting values, which, when detected, conditions the detector to reset the current value in the delay element of the integrator to a fixed value such as zero. Resetting the delay element momentarily lowers the order of the filter and speeds system response time in the presence of noise.

Abstract: In a digital television signal processing system, a special codeword, a Packet Alignment Flag (PAF), is inserted into an MPEG codeword bitstream to signify the presence of a Group of Pictures (GOP). The PAF immediately precedes a Picture Start codeword for an "I" frame, which initiates a GOP. A data packet under construction when a PAF appears is terminated since a GOP is intended to begin at a packet boundary. Such termination may result in an abbreviated packet of less than a prescribed number of codewords needed to complete a data packet. The last word of each packet is designated as such to facilitate the subsequent combining of data packets with respective headers. An incomplete data packet is filled with null (zeroed bits) words to make up a complete data packet with a prescribed number of words.

Abstract: Apparatus for compressing video information including digital data in horizontal or vertical blanking intervals of analog video signals includes circuitry (210) for retrieving such digital data. The retrieved digital data is formatted into auxiliary digital data packets. The analog video signal is compressed (214) according to, for example, the MPEG compression protocol and the auxiliary digital data packets are included (212) in the frame/picture headers of the compressed video signals.

Abstract: A block-matching method for generating motion vectors performs block matching on successively higher resolution images by refining motion vectors determined in a lower resolution image. At respective higher resolution images, search areas of limited search range are defined via a motion vector associated with corresponding image areas in the immediately lower resolution search. For at least one level of image resolution, the search blocks are overlapped to provide a plurality of search areas of limited search range for performing block matching searches for each block in the next higher resolution level.

Abstract: A memory efficient trellis demapper for demapping 8-PSK and 16, 32, 64 128 and 256-QAM trellis codes contains respective I-channel, Q-channel and remapper random access memory (RAM), an 8-PSK demapper logic network, and a selector switch. Each RAM includes a lookup table selectively programmed for each QAM code. The I-channel RAM and the Q-channel RAM forward their respective outputs through the switch as the trellis demapper output in response to an even power of 2 (i.e., 16, 64 or 256) QAM trellis code being selected. In response to an odd power of 2 (i.e., 32, 128) QAM trellis code being selected, the respective outputs of the I and Q channel RAMs are input to the remapper RAM, and the remapper RAM output is conveyed via the switch as the trellis demapper output. When an 8-PSK trellis code is selected, the output of the 8-PSK demapper logic network is conveyed via the switch as the trellis demapper output.

Abstract: In a compression system including a quantizer for quantifying a matrix of coefficients according to a matrix of quantizing values, and which is responsive to rate buffer occupancy for providing quantizing scale factors to modify the quantizing matrix, significant channel capacity may be salvaged without significant loss of image quality by incorporating apparatus to limit the minimum values of quantizing scale factors that are applied to the quantizing matrix.

Abstract: A method is disclosed for optimizing the operation of a packet transport system generating a packet stream carrying a plurality of component signals, and includes the following steps. First the packet stream is partitioned into successive groups, each group containing a predetermined number of packet slots. A plurality of lists are maintained, one associated with each packet slot in a group. A packet stream is generated by placing data representing a component signal selected in response to entries in the list associated with that packet slot into the packet slot. The contents of the plurality of lists are updated based on a predetermined parameter.

Abstract: A magneto optical disc system includes a disc having permanently recorded tracks overlain with magneto optical recording material. Data is recorded in the magneto optical material in tracks superimposed over the permanently recorded tracks, using the read-only data to define magneto optical tracks. The magneto optically recorded data is correlated with the prerecorded data for defining the location of data stored in the magneto-optic tracks.

Abstract: A disc playback system monitors coded information in the tracks of discs being played back in order to determine the radial position of the information pickup apparatus. Responsive to a disc stop command, the radial position is utilized to determine the angular speed of the disc, and thereby the speed of the motor that is rotating the disc. A time period, necessary for a predetermined signal which accelerates the motor in the reverse direction to stop the rotation of the disc, is calculated in response to the angular speed at the time the stop command is instituted. Thereafter the predetermined reversing signal is applied to the motor for the calculated period to stop the rotation of the disc.

Abstract: A digital high definition television receiver equalizer system includes an input adaptive feed forward filter (FFF 20), a carrier recovery network (46), and a slicer (40) in addition to an adaptive decision feedback filter (DFF, 30) for removing intersymbol interference. At the beginning of a blind equalizing interval the FFF is not adapted and the DFF operates as a linear filter with adapted coefficients for equalizing post-ghosts. Afterwards in the blind interval the FFF coefficients are adapted blindly for equalizing pre-ghosts. In a subsequent decision-directed mode the slicer output is used for adapting both the FFF and DFF non-linearly.

Abstract: A method of simultaneously transmitting and decoding an audio signal and an auxiliary signal which is inseparable from the audio signal includes the step of allocating a loudness level to the audio signal which is higher than the level of the auxiliary signal whereby the auxiliary signal is inaudible during playback of the audio signal and does not deteriorate the playback of the audio signal. The audio signal is encoded by dividing it into a number of frequency bands. The auxiliary signal is transmitted in one of the frequency bands at a level much lower than the level of the audio signal.

Abstract: In a digital audio-signal transmission process, digital audio signals are coded in sub-bands. One or more scaling factors are determined for each sub-band. The coded signals and scaling factors are transmitted in data blocks, then decoded and reproduced at a receiver. The data block contains several types of information including a header, error processing information, a CRC (cyclic redundancy check) protection word, audio information including a bit allocation table, scaling factor selecting information, one or several scaling factors per transmitted sub-band, filler bits, and supplementary information with audio-signal-dependent supplementary information. To improve the protection of the above-described sub-band coded audio signals against transmission errors, supplementary error protection information or an error protection bit is added to the data block instead of filler bits, in order to protect the scaling factors.

Abstract: A television signal receiver for processing an HDTV signal transmitted in a vestigial sideband (VSB) format with a one-dimensional data constellation includes a first carrier recovery network (18), an equalizer (20), and a second carrier recovery network (22, 30, 62). A multiple stage quantizer network (50, 66) exhibiting progressively finer resolution is associated with the operation of the equalizer for providing blind equalization without need of a "training" signal. The second carrier recovery network includes a phase detector (30) wherein a one-symbol delayed (312) input signal and a quantized (310) input signal are multiplied (316), and an unquantized input signal and a quantized (310) one-symbol delayed (314) input signal are multiplied (316), and an unquantized input signal and a quantized (310) one-symbol delayed (314) input signal are multiplied (318). Signals produced by the multiplication are subtractively combined (320) to produce an output signal representing carrier phase error.

Abstract: Apparatus for selecting predetermined ones of packets of signal components, from a signal stream of packets includes a control device, responsive to user selection and a transmitted program guide, for determining packet identifier codes, SCID's, for respective program signal components. SCID's, from respective packets in the signal stream, are successively compared with selected, stored SCID's. Transmitted signal components associated with appropriately detected SCID's are coupled to decryption apparatus. The decryption apparatus selects from a plurality of decryption keys in accordance with decryption flags include in transmitted signal packets. Decryption keys per se are provided by a smart card.

Abstract: An interpolation filter includes a subtractor, a weighting circuit and an adder, wherein the subtractor is conditioned to form differences of adjacent original samples, and the weighting circuit weights the differences with a predetermined value. The adder is arranged to a) pass an original sample; b) add a weighted difference to the original sample; and c) successively add the weighted difference to the previously generated sample to form successive samples.

Abstract: Apparatus requiring a plurality of control signals is provided with a fuzzy logic controller. The fuzzy logic controller is programmed with a plurality of control functions. Respective parameters determinative of the control signals are applied to the fuzzy controller in time division multiplex fashion, and concurrently respective control signals provided by the fuzzy controller are time division multiplex applied to respective control signal paths.

Abstract: An encoding method and apparatus for conditioning video signal to reduce contouring in images reproduced from compressed video signal involves preconditioning the video signal, prior to completion of compression, to effectively amplify noise in portions of the video signal representing relatively smooth image areas. In an exemplary embodiment, a memory is programmed at respective address locations to remap amplitude values of a digitized signal applied as addresses to the memory. The programming is arranged to enlarge a range of lower amplitude values, and to effectively pass higher amplitude values unaltered.

Abstract: A cassette loading facility has a guide frame arranged on a chassis in a fixed position. A receiving device is movable between a loading position, in which a cassette can be introduced and removed therefrom, and an operating position. The cassette is positioned on the chassis by means of positioning pins and catch apertures which are formed on the cassette housing. The catch apertures lock the cassette during its transportation between the loading and the operating position and also center it in the operating position.