Abstract: Scalable coding of audio into a core layer in response to a desired noise spectrum established according to psychoacoustic principles supports coding augmentation data into augmentation layers in response to various criteria including offset of such desired noise spectrum. Compatible decoding provides a plurality of decoded resolutions from a single signal. Coding is preferably performed on subband signals generated according to spectral transform, quadrature mirror filtering, or other conventional processing of audio input. A scalable data structure for audio transmission includes core and augmentation layers, the former for carrying a first coding of an audio signal that places post decode noise beneath a desired noise spectrum, the later for carrying offset data regarding the desired noise spectrum and data about coding of the audio signal that places post decode noise beneath the desired noise spectrum shifted by the offset data.

Abstract: A device of dynamic communication of information allows, on the average, non-integer bits per symbol transmission, using a compact code set or a partial response decoding receiver. A stream of selectable predetermined integer bits, e.g., k or k+1 data bits, is grouped into a selectable integer number of bit vectors which then are mapped onto corresponding signal constellations forming transmission symbols. Two or more symbols can be grouped and further encoded, so that a symbol is spread across the two or more symbols being communicated. Sequence estimation using, for example, maximum likelihood techniques, as informed by noise estimates relative to the received signal. Each branch metric in computing the path metric of a considered sequence at the receiver is weighted by the inverse of the noise power. It is desirable that the constellation selection, sequence estimation and noise estimation be performed continuously and dynamically.

Abstract: An encoding apparatus is provided for encoding a wideband digital signal, including an input for receiving the wideband digital signal, a splitter unit for splitting the wideband digital signal into a number of M sub signals, a data reduction unit for data reducing the sub signals and a formatting unit for assembling digital information including the data reduced sub signals into a digital output signal having a format suitable for transmission or storage. During a repeated encoding and decoding of a wideband digital signal in a subband encoding/decoding system or a transform encoding/decoding system, signal degradation may occur. In order to avoid this, the apparatus further including a variable delay unit coupled between the input and the splitter for realizing a delay, the length of which is controlled by a control signal, and a control signal generator unit for generating the control signal.

Abstract: An audio information bit stream including audio control bits and audio data bits is processed for transmission in a communication system. The audio data bits are first separated into n classes based on error sensitivity, that is, the impact of errors in particular audio data bits on perceived quality of an audio signal reconstructed from the transmission. Each of the n different classes of audio data bits is then provided with a corresponding one of n different levels of error protection, where n is greater than or equal to two. The invention thereby matches error protection for the audio data bits to source and channel error sensitivity. The audio control bits may be transmitted independently of the audio data bits, using an additional level of error protection higher than that used for any of the n classes of the audio data bits. Alternatively, the control bits may be combined with one of the n classes of audio data bits and provided with the highest of the n levels of error protection.

Abstract: A method to determine placement of sampled data within a data stream of a fixed rate communication channel is disclosed. The fixed rate communication channel transfers a serial flow of data packets over a serial or parallel communication channel. Each data packet has a header and a data stream. The method for transferring variable rate sampled data to a fixed rate communication channel begins by acquiring a sample of the variable rate sampled data. A data packet in which to place the sample is then determined. A location within the data stream where the sample is to be placed is also determined. A pointer to the location is placed within the header of the data packet. The sample is placed within the location within the data stream of the data packet and the data packet is then transmitted on the fixed rate communication channel.

Abstract: A DSV bit is inserted in an input data string by a DSV bit determining insertion unit. A modulation unit has a conversion table, and the element of the conversion table comprises the element for determining uniquely, and has a conversion rule that residues obtained by dividing the number of “1” in the element of a data string and the number of “1” in the element of a code word string to be converted by 2 are identically 1 or 0 for both residues. A channel bit string is modulated according to the conversion table, and further NRZI modulated by an NRZI modulation unit. Thus, DSV control can be performed with reduced redundancy.

Abstract: A mapper-based variable length coding method and decoding method and apparatuses therefor are provided. The mapper-based variable length coding method includes an inputting step for receiving symbol data to be coded and receiving element type information on the kind of symbol data, a coding step for generating a first code number corresponding to the received symbol data, a mapping step for selecting a second code number mapped with respect to selected element type information in mapping tables formed of second code numbers, each of which is appropriately mapped according to the first code number and the element type information, a codeword extracting step for generating a codeword corresponding to the selected second code number, and an outputting step for outputting the generated codeword. According to the methods and apparatuses, the advantages of a universal variable length code table can be maintained while preventing efficiency lowering of compression coding.

Abstract: The present invention relates to method and apparatus of converting a series of data words into modulated signals. This method divides a data word, which a sync signal is to be added in front or rear of when it is written in a recording medium, into two or more word segments, generates for each word segment a number of intermediate sequences by combining mutually different digital words with that word segment, scrambles these intermediate sequences to form alternative sequences, translates each alternative sequence into a (d, k) constrained sequence, checks how many undesired sub-sequences are contained in each (d, k) constrained sequence, and selects one (d, k) constrained sequence for recording on an optical or magneto-optical recording medium among the (d, k) constrained sequences not having the undesired sub-sequence. Applying this method to a modulating device, DSV control can be conducted by much simpler hardware.

Abstract: A method and system of operating a digital data decoder. In accordance with this method, a first stream of encoded data is transmitted to the decoder, and a second stream of encoded data is stored in a memory device. One of the first and second streams of encoded data is selected, and the decoder is used to decode that selected stream of encoded data. This second stream of data could have been placed in the memory device by other devices or processes present in an STB system. In this case, all the decoder needs to process the data is a pointer to it and some additional information about, for example, its size. Since the processor has access to all memory, it can do any necessary parsing/manipulation required by the stream format. This provides a large degree of flexibility in this area. The processor can then pass location and attributes of data to the decoder. This also minimizes data movement to/from memory, reducing bandwidth requirements.

Abstract: An encoder is arranged to add a binary code bit to block of a signal by selecting, within the block, (i) a reference frequency within the predetermined signal bandwidth, (ii) a first code frequency having a first predetermined offset from the reference frequency, and (iii) a second code frequency having a second predetermined offset from the reference frequency. The spectral amplitude of the signal at the first code frequency is increased so as to render the spectral amplitude at the first code frequency a maximum in its neighborhood of frequencies and is decreased at the second code frequency so as to render the spectral amplitude at the second code frequency a minimum in its neighborhood of frequencies.

Abstract: A method and system for encoding data for transmission over a transmission channel in a digital communication system, the method including selecting an appropriate variable length product code for variable length data to be transmitted, and encoding the data by means of the selected product code. The system includes a code selecting unit arranged to select a variable length code which is most suitable for variable length data to be encoded, and an encoder encoding the variable length data with the selected variable length product code.

Abstract: The present invention is embodied in a method an apparatus for reducing the number of leased E1 lines needed to backhaul communication traffic in a satellite communication situation. The present invention receives and decompressed a satellite signal. A copy of the compressed signal is then encoded into the least significant bits (LSBs) of the decompressed signal. The decompressed signal having the embedded information may be routed to an international PSTN network over leased communications lines. However, the compressed information is extracted from the decompressed signal and sent across the E1 lines, thereby conserving communication bandwidth and reducing the number of leased lines required. After passing through the E1 lines the information is decompressed and connected to the international PSTN network. Alternatively, the decompressed signal having the embedded information may be distributed to local PSTN networks, which interpret decompressed signals.

Abstract: A data compressing method which can efficiently compress image data containing color data is provided. A compressed data expanding method which can expand the compressed data at high speed is provided. Image data containing color data are compressed into image data including: address fields code A, code B, code C which hold addresses of color RAMs storing color information corresponding to the color data; classification fields which, when the color RAMs are classified into prescribed categories A, B, C, hold classification information of the categories including the color data; and run length fields RL which hold numbers of successive repetitions of color data. To expand the compressed image data, the classification fields are decoded to determine the categories in which the color data are included.

Abstract: In order to transmit variable length coded data blocks while reducing data loses caused by code errors, the control circuit 7 makes a group of a plurality of variable length coded data, a fixing length circuit 9 fixes the code length of each of the variable length coded data thus grouped so that the data blocks each have an average code length and then makes a group of the data blocks in that condition, a header outputting circuit 8 prepares a header including information on the grouped data blocks and a synchronization word, and a control circuit 7 controls a switch SWC so that the prepared header and the group of data blocks are output through an output terminal 2. On the decoding side, the data blocks are synchronized/decoded by obtaining the code length of the group of data blocks and the number of the data blocks with reference to the location of the synchronization word in the header and information on the data blocks.

Abstract: A run length encoder for encoding DCT coefficients obtained in a DCT, a quantization, and a scanning steps in block units to output an encoded (run, level) symbol, and outputting a predetermined (run, level) symbol if the obtained DCT coefficients of the block unit are all zero, comprises a run length encoding core for receiving the DCT coefficients and outputting the (run, level) symbol; a zero coefficient detector for detecting whether the DCT coefficients are `0` or not; a zero block detector for receiving an output from the zero coefficient detector to detect whether all of the DCT coefficients of each block are `0` or not; and an output selector for selecting the 2-dimensional symbol outputted from the run length encoding core to output a (run, level) symbol or a predetermined (run, level) symbol, if the block determined in the zero block detector is non-zero or zero block, respectively.

Abstract: The invention is a process and apparatus for estimating a bit budget in a circuit for compressing digital data, especially digitized television signals. Signals represented by N-bit coded samples, are estimated based upon the probability of a bit of given order having a given value (0 or 1) out of M binary words representing M samples of the signal. An entropy calculation is performed on the basis of the probabilities corresponding to the N bits with the sum of all the entropies corresponding to the desired estimate.

Abstract: A data encoding method having a prediction setting process that designates a numerically superior symbol as either a "0" or a "1", and the other one is designated as a numerically inferior symbol. Then a binary bit string composed of "0"s and "1"s is input, and the numerically superior symbol is predicted to continuously repeat for n symbols, where n is set as a prediction bit number. A prediction result output process outputs a prediction correct signal that is either a "0" or a "1" when a prediction is correct for the observed series. The process then moves to an operation to perform encoding of a bit series containing the next n symbols, or otherwise outputs the other signal (i.e., that is not used to represent that the prediction is correct) as a prediction failure signal.

Abstract: An encoder which counts the length of a data produced by the variable-length encoding, and time-division-multiplexes information of the data length to the variable-length encoded data. An encoder which time-division-multiplexes information of the number of bits after a fixed partition used in the error-correction encoding to the initial bit of a variable-length code to a variable-length encoded data, and transmits them. An encoder which, when a variable-length code for one symbol of the variable-length encoding extends over a partition used in the error-correction encoding, inserts a special code before the partition, or guarantees that the top of the partition is always at the top of the variable-length code. An encoder which obtains the sum of fields and the difference between fields, and performs on these values the orthogonal transform to encode them.

Abstract: A variable encoding puncturer, for encoding data in response to a variable encoding rate, in a digital broadcasting communication encoder, including a control unit for controlling an alignment of input data and a selection of a compression matrix, and an alignment of output data according to a variable encoding rate inputted from an external circuit; an input data aligning control unit for outputting the aligned data in parallel in response to an input clock signal after aligning data with a variable encoding rate in response to a control of the control unit; an input buffer for storing, in order, the aligned data from the input data aligning control unit; an output data aligning control unit for selecting the aligned data from the input buffer according to the variable encoding rate under the control of the control unit and for outputting the selected data; and an output buffer outputting the selected data encoded data from the output data as aligning control unit in response to an output clock signal.

Abstract: A transmitting method of digital data whereby information data can be reproduced at a high precision. In order to retain digital data in sectors comprising a plurality of sync frames and sequentially transmit, the sync frame is comprised of the sync signal and the run length limited code which satisfies the limitations of the minimum run length and the maximum run length, and the sync signal includes the sync pattern constituted by a bit pattern of a run length that is longer than the maximum run length by only 3T and addition bit patterns which are arranged before and after the bit pattern and each of which has a run length that is longer than the minimum run length. The sync signal includes a specific code which indicates a position in the sector and which enables the DC control to be performed.

Abstract: A digital modulation apparatus applies a method for converting data words to runlength-limited code words using plural conversion tables. The data words are converted to code words that significantly suppress the low frequency component of the final nonreturn-to-zero inverted signal.This digital modulation apparatus includes ROM tables for storing plural conversion tables containing the runlength-limited code words corresponding to the data words; end-runlength memories and evaluators for determining whether the runlength-limit constraints are satisfied in the interconnection between two consecutive code words when the data words to be converted are supplied; and a DSV controller for storing each of the code words that can be selected from two conversion tables to buffer memories when the runlength-limit constraints are satisfied, and selecting the code words wit the greatest effect suppressing the low frequency component in the obtained signal when the code words are NRZI converted.

Abstract: In a signal processing method to compress digital audio data by a block floating process, digital signal encoding/decoding apparatuses prevent deterioration of sound quality of the digital audio signal and improve the compression ratio of the digital audio signal when the digital audio signal is converted on a frequency axis per predetermined time frame, and data on the frequency axis is then divided into a plurality of blocks to be recorded, otherwise, bits are allocated per block to compress the digital audio signal for minimizing transmitted parameters. Also, encoding/decoding methods are provided to enable highly efficient encoding/decoding without recording or transmitting word length, allowing one to obtain a high-quality audio signal by allocating bits conventionally held by the word length to hold quantization data of a spectrum signal.

Abstract: There is provided a coding apparatus which comprises a coding section for variable-length coding an input signal on a predetermined unit basis, an output section for outputting the data which was variable-length coded by the coding section on the predetermined unit basis, and an error correction adding section for adding an error correction code to the coded data outputted from the output section.

Abstract: A method generates a reduced number of values representing a sequence of grouped data values and partitions the reduced number of values by first mapping data values into groups of symbols and then partitioning the resulting stream of symbols. The digits representing the first data value in each group are replaced with symbols from a first alphabet. The most significant digit of the second data value in each group and the sign of that second data value are also represented by a symbol from the first symbol set, while the remaining significant bits of the second data value in each group are represented by symbols from a second symbol set. A stream of symbols which represent a sequence of grouped data values is partitioned into first partition symbol groups and second partition symbol groups. Each first partition symbol group comprises the symbols representing the first data value in each group and also the symbol representing the least significant bit of the second data value which follows.

Abstract: Data items associated with different locations in a spatial field of locations are written in a memory. The memory comprises a length memory in which for each location there is stored a length code which indicates the memory length required for the data item. For the reading of a data item associated with a location, the address of the data item is calculated by reading the length codes for the data items of preceding locations from the memory and by summing the lengths indicated.

Abstract: An encoder counts the length of a data produced by the variable-length encoding, and time-division-multi-plexes information of the data length to the variable-length encoded data. Art encoder time-division-multiplexes information of the number of bits after a fixed partition used in the error-correction encoding to the initial bit of a variable-length code to a variable-length encoded data, and transmits them. An encoder, when a variable-length code for one symbol of the variable-length encoding extends over a partition used in the error-correction encoding, inserts a special code before the partition, or guarantees that the top of the partition is always at the top of the variable-length code. An encoder obtains the sum of fields and the difference between fields, and performs on these values the orthogonal transform to encode them.

Abstract: A method and apparatus for encoding an input signal in which the input signal is transformed into frequency components which are encoded by quantization from one encoding unit to another. The information specifying zero encoding units among the encoding units in which encoding is done on the assumption that all frequency components contained in them are deemed to be zero are encoded, is encoded, while the quantization step information of the zero encoding units is outputted without encoding. With the encoding method and apparatus, the number of the encoding bits may be decreased while deterioration in the input signal is prohibited for improving the encoding efficiency.

Abstract: In a signal processing method to compress digital audio data by a block floating process, digital signal encoding/decoding apparatuses prevent deterioration of sound quality of the digital audio signal and improve the compression ratio of the digital audio signal when the digital audio signal is converted on a frequency axis per predetermined time frame, and data on the frequency axis is then divided into a plurality of blocks to be recorded, otherwise, bits are allocated per block to compress the digital audio signal for minimizing transmitted parameters. Also, encoding/decoding methods are provided to enable highly efficient encoding/decoding without recording or transmitting word length, allowing one to obtain a high-quality audio signal by allocating bits conventionally held by the word length to hold quantization data of a spectrum signal.

Abstract: A coding scheme for transmitting messages particularly between computers is described. Messages are transmitted in packets which include at least a data portion and a terminator. Out of a predetermined set of symbols, sixteen data symbols and at least one control symbol is selected. The terminator token is generated to constitute the symbol and a six-bit symbol representing checking bits.

Abstract: A binary code is divided into 2-bit data units. Pulse position modulation is performed on each unit rather than on each bit. Since a pulse is not formed for each bit, the transmission interval and transmission frame interval for the modulated signal is shortened, thus enabling high speed transmission. Since the pulse interval of the signal contains the information of the 2-bit data unit, only the leading edge of the pulse needs to be detected. This feature allows reliable demodulation even under adverse conditions such as a long-distance transmission route or a noisy transmission route. Since there is no need to demodulate by comparing each bit with an immediately preceding bit, complex demodulation schemes and decoding registers are not needed on the receiving side. Since the width of the pulse does not contain any transmission information, the pulse width is made as short as possible, thereby reducing battery consumption within the transmitter.

Abstract: A variable-length decoder variable-length-decodes a received variable-length-encoded data. The variable-length-encoded data is bit-stuffed in each data block to create data portions with a predetermined number of bits. Frame start codes representing a start of each frame and mass of macroblock start codes distinguishing between a plurality of masses of macroblocks are inserted into the data. Synchronization of data between frames and masses of macroblocks are accomplished via: a first-in-first-out (FIFO) memory which stores encoded data; a decoder which variable-length-decodes the input data in response to a control signal and generates an end-of-block (EOB) error signal when an EOB is not found; a decoding interface which interfaces between the decoder and a timing controller; and a timing controller which synchronizes decoding by use of start and initialization signals.

Abstract: An apparatus for variable-length-coding input symbols using a plurality of variable-length-code tables includes N variable-length-code tables each having a symbol-codeword association different from the others according to statistics regarding the symbols and a variable-length-coding device for coding the input symbols according to each of the variable-length-code tables for every block in a predetermined block data unit, for generating codewords, and for providing both table information representing each of the variable-length-code tables utilized in generating the respective codewords and a control signal indicating that variable-length-coding to a predetermined block data unit has been completed.