Abstract: A receiver is arranged for receiving a transmitted quadrature amplitude modulated (QAM) signal representing successive symbols, and including an in-phase (I) component and a quadrature (Q) component. In such a receiver, a timing recovery system includes a source of samples representing the QAM signal produced at a fixed frequency. A first chain of processing circuitry for the I component includes a first demodulator, coupled to the sample source, for demodulating the I component of the QAM signal to baseband; and a first interpolator, coupled to the first demodulator and responsive to a control signal, for producing I component samples taken at times synchronized to the transmitted symbols.

Abstract: An optical recording and/or playback system having tracking and focus regulating circuits. Mechanical shock and/or disc defects are detected and the adverse effects on the tracking and focus regulating circuits are reduced.

Abstract: Apparatus for sampling a signal parameter of a plurality of data signals is disclosed which comprises a plurality of sources (5) of data signals. Each data signal includes sequential groups of data. Each group of data in all of the data signals has the same fixed predetermined time duration, and includes sequential blocks of data. A plurality of parameter determining circuits (16) are each responsive to a respective one of the data signals, and produce sequential signals (COMPLEXITY) having values representing the signal parameter for each of the sequential blocks of data in the data signal. A plurality of accumulators (31) are each responsive to a respective one of the parameter representative signals, and produce a signal representing the cumulative parameter value of the data signal.

Abstract: A transport stream encoder comprises a plurality of component signal sources. One of the component signals sources is a source of an opportunistic data component signal carrying a block of data having a predetermined size to be transferred within a predetermined period of time. A packet generator is coupled to the plurality of component signal sources, and produces a composite packet stream, partitioned into successive groups containing a plurality of packet slots. A memory stores a plurality of priority lists respectively associated with the plurality of packet slots. Each priority list contains a plurality of entries, and each entry contains data representing a respective one of the plurality of component signal sources. A scheduler is responsive to the entries in the plurality of priority lists and conditions the packet generator to generate a packet for each one of the packet slots.

Abstract: A system of the present invention addresses the difficulty of aligning a reference sync byte at the beginning of a data packet during situations where the system experiences severe problems such as arbitrary resets/restarts or transmission disturbances. Specifically, the sync byte at the beginning of the data packet is automatically aligned with the beginning of a data acquisition interval when data is requested, even when there are arbitrary system resets/restarts. The alignment of the first data packet following a system reset is facilitated by the use of a Start Of Packet flag concurrent with the reference byte, together with a controlled logic network.

Abstract: An MPEG compatible decoder receives encoded, compressed data in the form of image representative pixel blocks. The decoder includes a frame memory (20) for storing reconstructed pixel blocks incident to the decoding process. The previously decompressed data is re-compressed (30) before being written to the memory. Stored decompressed data is decompressed for display (34, 26), or as needed for decoding functions such as motion compensation processing (32, 22). The compression performed before writing data to memory is block-based compression using compressed data from one of two different compression paths (FIG. 3, 314, 320) which compress a given pixel block simultaneously.

Abstract: A decoding method minimizes the use of incorrect program specific information (PSI) parameters across program boundaries and provides default video and audio outputs for reproduction during error conditions. Program representative packetized datastreams incorporating PSI suitable for use in recovering data content of the program are decoded. PSI packets in the datastream are identified and a parameter within the identified PSI data is used to determine whether the identified PSI data is to be used for decoding the program content, irrespective of previous PSI content. Current PSI is updated with the identified PSI data in response to the parameter. Program content packets are identified using the current PSI. The program content packets are assembled into a decoded datastream using the current PSI. The current PSI may also updated with the identified PSI data irrespective of the content of the identified PSI data, provided that there is an absence of a PSI content error indication.

Abstract: A television receiver includes an MPEG decoder for providing decoded pixel blocks. Decoded pixels are recompressed prior to storage in frame memory. In the recompression process a reference first pixel is compressed as a function of a pixel block parameter. A reconstructed reference pixel value is used in a prediction network when reconstructing remaining pixels of the pixel block prior to display. A first pixel processor accurately compresses a reference pixel which prevents the propagation of a prediction error throughout the reconstructed block.

Abstract: Program specific information (PSI) is formed suitable for use in recovering data content of a program in the form of a packetized datastream. Packet identifiers (PIDs) that identify individual packetized datastreams constituting the program are renumbered and corresponding packetized datastreams that constitute different programs are given the same PID. A program map table (PMT) is created that associates the renumbered PIDs with the individual packetized datastreams constituting the program. A program association table (PAT) is also created for associating the program with PIDs that identify packets comprising the PMT. A parameter may be employed within the PSI to indicate that the PSI is to be applied in subsequent processing of the program irrespective of a substantive difference between the PSI and previous PSI content. In addition, the PSI may incorporate a version number that is varied between successive occurrences of the PSI irrespective of substantive change in PSI content.

Abstract: A method is disclosed for decompressing in-place an adjusted monotone compressed file having a first portion containing compression codewords and a second portion containing plain text, into a decompressed file having a size and containing plain text. The method comprising the following steps. First, a memory buffer is allocated having the size of the decompressed file. Then the adjusted monotone compressed file is stored in the bottom of the buffer. Finally, the compression codewords in the first portion of the adjusted monotone compressed file are decompressed to produce plain text of a corresponding portion of the decompressed file in the top of the buffer. A method is also disclosed for compressing a source file into an adjusted monotone compressed file. The method comprises the following steps. First, the source file is monotone compressed into a compressed file containing compression codewords.

Abstract: An adaptive trellis decoder seamlessly switches between multiple input signal formats. The trellis decoder employs a code sequence detection system, described in the context of an exemplary Viterbi decoding system, that detects codes in an input interleaved packet data signal. The code sequence detection system also reduces the delay (latency) between the input of encoded data and the output of decoded data. The code sequence detection system provides branch metric values in response to the input interleaved packet data signal which exhibits one of a plurality of signal formats, e.g., partial response and normal formats. A Viterbi decoder decodes the packet data signal to produce a decoded output in response to the branch metric values which include a substantially replicated value associated with one of the formats. The Viterbi decoder includes a comparison network that provides decision data in response to branch metric values associated with the trellis encoded data packets.

Abstract: An adaptive trellis decoder seamlessly switches between multiple operational modes. The trellis decoder employs a code sequence detection system that detects codes in input interleaved packet data. The code sequence detection system also reduces the delay (latency) between the input of encoded data and the output of decoded data. The code sequence detection system processes video data in the form of groups of interleaved trellis encoded data packets and includes a traceback network that identifies a sequence of antecedent trellis states, in accordance with a state transition trellis. The traceback network identifies the antecedent states for collocated interleaved packets in response to decision data associated with trellis state transitions. Output trellis decoded data is provided in response to the identified sequence of antecedent trellis states. The decoder can also provide a plurality of trellis decoded data sequences.

Abstract: An adaptive trellis decoder seamlessly switches between multiple operational modes. The decoder switches between multiple modes and accommodates data type transitions using a single state transition trellis with a predetermined number of states. The system decodes trellis encoded video data encoded in different formats respectively containing different numbers of levels associated with different modes. The decoder system adaptively operates in response to a configuration signal distinguishing between the modes, and employs a state transition trellis with the same number of trellis decoding states for decoding encoded data of different formats. The state transition decoding trellis may also be reset to a predetermined state in response to a synchronization signal generated as a result of a transition from one type of data to another or in response to a mode change.

Abstract: A storage medium format for a storage medium containing packetized data programs includes packet identifiers (PIDs) that identify individual packetized datastreams constituting a program. The data format facilitates the association and assembly of the packetized datastreams of the program by a decoder, independent of PID de-mapping data. The PIDs include a base PID for identifying one datastream and a second PID of predetermined offset value to the base PID for identifying a second datastream. Corresponding packetized datastreams that constitute different programs are given the same PID. The storage medium format may also include program specific information (PSI) suitable for use in recovering data content of a program. The PSI includes an MPEG-like program map table (PMT) and an MPEG-like program association table (PAT) and incorporates a parameter suitable for commanding a decoder to apply the PSI in decoding the program irrespective of previous PSI content.

Abstract: A system for dynamically allocating a resource is disclosed which includes a plurality of resource users and a resource having a maximum utilization level sharable among the plurality of resource users. A plurality of need analyzers, associated with respective resource users, dynamically generate respective signals (COMPLEXITY), each representing the relative need for the resource by the associated resource user. A plurality of access controllers, associated with respective resource users, control access to the resource by the associated user in response to an allocation signal (CONTROL). A resource allocator dynamically generates allocation signals (CONTROL), representing allocated resource utilization levels for associated users, in response to the plurality of need representative signals (COMPLEXITY) from the need analyzers.

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 (318). Signals produced by the multiplication are subtractively combined (320) to produce an output signal representing a carrier phase error.

Abstract: A transmission processor (16) receives an input packetized datastream (FIGS. 6-9; FIGS. 15-18 signal A) containing packets of data bytes including MPEG coded video information. The transmission processor outputs a symbol datastream (FIGS. 15-18 signal F) representing a sequence of data fields (FIG. 1) comprising groups of data segments (X) with an associated field sync segment. The transmission processor inserts overhead information. e.g., FEC error coding information, into each data segment, and inserts the longer duration field sync overhead segment between groups of data field segments. The frequency of the transmission processor input byte clock (SC/2, FIG. 6; FIG. 15) an integer sub-multiple of an output symbol clock (SC) frequency. The input datastream exhibits constant uniform inter-packet data gaps and a constant uniform data rate, thereby facilitating the seamless insertion of the field sync overhead segment into the datastream without interrupting the datastream.

Abstract: A dynamically configurable video signal processing system partitions and encodes data using a variable number of data segments and variable data resolution. The system partitions data into a variable number of data segments by predicting, as a function of the data rate, first and second distortion factors for the data partitioned into first and second numbers of data segments. The first and second distortion factors are mutually compared and the data is partitioned into the number of data segments which exhibits the lower distortion factor value. First and second distortion factors for the data encoded with first and second data resolutions are also predicted. The first and second distortion factors are similarly compared and the data is encoded with the resolution exhibiting the lower distortion factor value.

Abstract: A television receiver with an MPEG decoder is configurable for full high definition decoding and display, or reduced cost lower definition display. The MPEG decoder (10-33) uses a controllable dual-mode data reduction network selectively employing horizontal detail reduction (29) and data re-compression (30) between the decoder and the decoder frame memory (20) from which image information to be displayed (27) is derived. The amount of data reduction is manufacturer selected in accordance with the resolution of the display device, e.g., equal to or less than high definition resolution. The frame memory size is also manufacturer selected in accordance with the resolution of the display device.

Abstract: A distributed computer system, as for transmitting and receiving executable multimedia applications, includes a source of a continuous data stream repetitively transfering data representing a distributed computing application and a client computer, receiving the data stream, for extracting the distributed computing application representative data from the data stream, and executing the extracted distributed computing application.