Abstract: An apparatus includes a quantizer to generate a quantized signal from an input signal and a function unit may be included to generate an output signal by applying a predetermined function to the quantized signal. The apparatus further may include a correction unit to compensate for distortion in the output signal.

Abstract: The present invention provides a digital spread spectrum frequency synthesizer that comprises a noise-shaped quantizer, a divider and an adjustment means. The noise-shaped quantizer is used to quantize a period control word to a time-varying value. The divider is used for generating an output signal by means of dividing a reference signal by the time-varying value, the output signal feeding back to the noise-shaped quantizer so that the noise-shaped quantizer generates the time-varying value in response to the feedback output signal. The adjustment means is used to adjust the period control word by a period offset in response to the output clock. Accordingly, the frequency synthesizer of the present invention can provide a very precise frequency synthesizer featuring a precision spread spectrum clock and jitter stability as well.

Abstract: A digital data system (100) provides 1-D, 2-D and 3-D capability and multi-band channel capability. Improved filter banks are created by generating a filter bank having an analysis portion and synthesis portion and obtaining wavelet coefficients (302) for each portion. The wavelet coefficients are expressed in a format capable of canonical signed digit (CSD) representation, such as integers (302). The canonical signed digit (CSD) representation is controlled by a value, N, selected to control resolution of the CSD coding. Optimized CSD-coded wavelet coefficients are used as filters for data signals (318).

Abstract: A shift register receives a quantization difference signal separated into a mantissa part and an exponent part and bit-develops the mantissa part. A shift arithmetic operation control circuit bit-shifts the bit-developed mantissa part in accordance with a value of the exponent part. An overflow detection bit is added to the MSB of the shift register and detects the overflow of the bit-shifted mantissa part. When the overflow of the mantissa part is detected, a selector replaces the bit-developed mantissa part with a predetermined upper limit value and outputs it as a prediction signal. When the overflow is not detected, the selector outputs the bit-developed mantissa part as a prediction signal. An ADPCM decoder having high audio quality is provided by simple processes and construction.

Abstract: A method and apparatus reliably encode and decode information over a communication system. The method includes transforming two coefficients into two pairs of random variables, one random variable in each pair having substantially equal energy as one random variable in the other pair. The method further includes quantizing each of the pairs of random variables and entropy coding each quantized random variable separately creating an encoded bitstreams. The encoded bitstreams are received by a decoder which first determines which channels of the communication system are working. The encoded bitstream is entropy decoded, inversed quantized and inversed transformed. An inverse transform performs three different transformations depending upon which channels are working, i.e., whether the first, second or both channels are working.

Abstract: A device for receiving digita1 signals comprising at least one receiving antenna for receiving signals, a measuring means for determining parameters of relevance to signal quality of signals received by the antenna, and a digitizer for the signals received by the antenna. The digitizer is controlled to optimize reception of the signals on the basis of the parameters determined by the measuring means.

Abstract: A device for performing predetermined processing on an input signal that may have a signal amplitude of more than one bit. The input signal is obtained by subjecting one-bit serial signals to predetermined signal processing, wherein the signal amplitude of more than one bit is converted to a one-bit serial signal by accumulating the signal amplitudes that exceed one bit, delaying the accumulated signal on the basis of the input signal, and outputting the accumulated signal.

Abstract: An apparatus for decoding audio data that is capable of reducing the amount of calculations that are performed during the arithmetic decoding of an audio signal coded by bit sliced arithmetic coding (BSAC) to improve the performance of a decoder and a method thereof are provided.

Abstract: An analog/digital gain control device avoid some of the requirements associated with the nature of a closed-loop AGC circuits and which meets the remaining requirements without much difficulty uses an analog to digital conversion method that increases the number of effective ADC bits by compressing the baseband input analog signal using a logarithmic circuit. After the compressed analog signal is converted into a digital signal, a digital anti-log process or look-up table (LUT) is used to expand the digital signal back to the original linear scale. The word size of the output of the anti-log process is larger than the input word size due to the nature of the anti-log function. To reduce the word size of the digital signal an open loop normalization technique can be applied.

Abstract: A distortion removal system for reducing the quantization distortion that results from quantization of a signal by sample-by-sample quantization techniques is disclosed. The distortion removal system uses the signal previously quantized with the sample-by-sample quantization techniques to determine an expected quantization distortion. The expected quantization distortion is determined for each of a plurality of frames of the signal. The expected quantization distortion is removed from each of the frames of the signal.

Abstract: Systems and methods are described for full bridge integral noise shaping for quantization of pulse width modulated signals. A method for full bridge integral noise shaping comprises: receiving a first and a second reference PWM signal; summing the first and second reference PWM signals with a quantization error correction; quantizing the sum into a first and a second output PWM signal; differentially integrating the first and second reference PWM signals and the first and second output PWM signals according to a full bridge integral noise shaping algorithm to obtain the quantization error correction. An apparatus for performing a full bridge integral noise shaping quantization of a pulse modulated signal, includes: a single-ended to differential conversion circuit; and a full bridge INS quantizer circuit, coupled to the single-ended to differential conversion circuit.

Abstract: An apparatus and method for detecting a connection to a data transmission network functions by detecting the network signal energy on a network cable while avoiding the problems of excessive power consumption and generation of excessive electrical noise. By monitoring the receive network lines and determining if there is electrical energy on the cable in the form particular to the type of network supported by the network adaptor card, the host computing device can power-down the transceiver associated with the network adaptor card until an active network connection is detected.

Abstract: A method and signal processing apparatus for reducing the number of bits of a digital input signal (Mi), includes adding a pseudo-random noise signal (Na) to the digital input signal (Mi) to obtain an intermediate signal (Di), the pseudo-random noise signal (Na) being defined by noise parameters (Np), and quantizing the intermediate signal (Di), having a word length of n bits, to a reduced word-length signal (Me) having a word length of m bits, n being larger than or equal to m. The method further includes quantizing the intermediate signal (Di) using a first transfer function which is non-linear, the first transfer function being defined by non-linear device parameters (NLDp).

Abstract: The present invention relates to a menu picture generating method and to a recording device for recording a menu picture on a record carrier (20), wherein a key frame picture is scaled and then compressed before being assembled by a slice replacement operation. The entire menu picture assembly operation is performed in the compressed picture domain, wherein no pictures need to be decoded and only small part of the menu picture, corresponding to the scaled key frame picture, needs to be encoded. Thereby, the normal encoding-decoding pipeline of the recording device is not required for menu generation, such that hardware and software requirements can be reduced.

Abstract: An apparatus for converting a digital input signal to an analog signal for transmission. The input signal can include more than one carrier signal. A plurality of delta-sigma modulation loop circuits are connected in an increasing order of operating frequency so as to reduce a word length of the input signal. A tuning circuit adjusts the signal frequency to a transmitting frequency for conversion to analog by a digital-to-analog converter. A first loop circuit is implemented using CMOS gates, and a second loop circuit and the tuning circuit are implemented using indium phosphide gates. The apparatus allows a high-resolution, wide-band RF multiple-carrier signal to be re-quantized to a lower-resolution signal while an acceptable signal-to-noise ratio is maintained.

Abstract: Method and system for implementing digital filters in the data path of a Pulse Code Modulated (PCM) modem to allow efficient transition of a second analog to digital conversion process in a communication system including monitoring the upstream data path of the communication system to decode the V.34 portion of the data transmission which occurs during the handshake phase of the modem call, where the information contained in the upstream data channel during the handshake phase allows the communication system to determine the manner in which the PCM modem is training and transmitting data to the client modem.

Abstract: An insertion-based error concealment method and apparatus are provided whereby, instead of directly inserting white noise, a filter is created to shape the white noise. The filtered white noise is then used to replace lost data. The method of the present invention is implemented by first estimating the power spectrum of the previous frame; then designing a filter with transfer function H(f), where |H(f)|2=the estimated power spectrum; and finally generating the replacement packet using noise which has been spectrally modified by the filter. The resulting filtered noise has the same power spectrum as the previous packet but is not highly correlated with it.

Abstract: System and method for analog signal generation and manipulation in an ultra-wideband (UWB) transmitter. A preferred embodiment comprises a digital portion 305 of an UWB transmitter (for example, transmitter 300), which is responsible for encoding a data stream to be transmitted, and an analog portion 330. The analog portion 330 creates a stream of short duration pulses from the encoded data stream and then filters the stream of short duration pulses. To simplify the generation of the short duration pulses, a quantized representation of the short duration pulse is used. The quantized representation is created via the use of control signals that by coupling differential amplifiers together (such as amplifier 611), generate a voltage drop across a resistor (such as resistor 619) and hence, a current.

Abstract: The invention proposes a device for generating, from incoming signal values (Xi,n), soft-values (Yi,n) to be input into a channel decoder of a communication device for use in a wireless communication system, comprising truncation means (24, 26, 28) for truncating the incoming signal values (Xi,n) such as to fall within a predetermined limit value range, and normalization means (30, 32) for normalizing the truncated signal values (Xti,n) such as to fit to an input range of the decoder. According to the invention, the truncation means (24, 26, 28) are adapted to determine the boundaries of the limit value range in dependence on information representative of a signal-to-noise ratio of the incoming signal values (Xi,n). The truncated signal values (Xti,n), after normalization, then are output as said soft-values (Yi,n).

Abstract: Apparatus, and an associated method, for a direct conversion receiver by which to selectably increase the sensitivity of the receiver. The direct conversion receiver includes a baseband amplifier positioned in front of a baseband filter, and coupled to receive a direct-converted baseband signal. The gain at which the baseband amplifier amplifies the signal provided thereto is selected, in combination with gains applied to other amplification elements of the direct conversion receiver to distribute the gain across the receive chain. When a signal received at the receiver includes a large interfering signal component, the gain of the baseband amplifier is reduced to lessen the possibility that the amplified signal become saturated. A gain controller controls the gain of the amplification elements.

Abstract: A system and method of creating a highly efficient digital amplifier which can take either analog or digital inputs, and produce a high power accurate representation of the input to drive speakers or other low impedance load is described. The system employs a transition detector and delay unit which allows the comparator of the signal modulator to ignore its inputs for a pre-determined number of subsequent clock cycles once an output transition has been detected. Through the use of faster clocks and variable clock cycle skips upon the comparator's output transition, finer resolution of the feedback's clock period for noise-shaping purposes is achieved. Finer resolution of the clock period allows the present invention to employ a more aggressive noise-shaping than previously possible.

Abstract: A video compression process speeds the optimal choice of quantizers for compressing a data stream by setting up the optimization problem as a path-optimization problem in configuration space and finding the lowest cost path through the configuration space. The process begins with a starting node (or “state”) and propagates least-cost waves through the space until a path is completed to the end. The process may continue using uncompleted paths while their costs are less than the end state, beginning with the lowest cost incomplete path, until an improved path is found. The process may further continue, for a time constrained process, until time runs out or all useful possibilities are exhausted.

Abstract: An apparatus and method for detecting a connection to a data transmission network functions by detecting the network signal energy on a network cable while avoiding the problems of excessive power consumption and generation of excessive electrical noise. By monitoring the receive network lines and determining if there is electrical energy on the cable in the form particular to the type of network supported by the network adaptor card, the host computing device can power-down the transceiver associated with the network adaptor card until an active network connection is detected.

Abstract: A shift register receives a quantization difference signal separated into a mantissa part and an exponent part and bit-develops the mantissa part. A shift arithmetic operation control circuit bit-shifts the bit-developed mantissa part in accordance with a value of the exponent part. An overflow detection bit is added to the MSB of the shift register and detects the overflow of the bit-shifted mantissa part. When the overflow of the mantissa part is detected, a selector replaces the bit-developed mantissa part with a predetermined upper limit value and outputs it as a prediction signal. When the overflow is not detected, the selector outputs the bit-developed mantissa part as a prediction signal. An ADPCM decoder having high audio quality is provided by simple processes and construction.

Abstract: Glitch filters, methods, and computer program products that utilize the generally monotonically increasing characteristics of the expected levels of code points to detect and remove noise spikes by replacing values in the code point sequence with new values based on the code points around a suspect value are provided. Measured values associated with two code points in the sequence of code points which are immediately higher in the sequence of code points than a code point of interest are evaluated so as to select a larger value of the two code points in the sequence as a first reference value. The first reference value is compared with a measured value associated with a code point in the sequence of code points immediately lower than the code point of interest to determine if the first reference value is smaller than the measured value associated with the code point in the sequence of code points immediately lower than the code point of interest.

Abstract: A method and apparatus reliably encode and decode information over a communication system. The method includes transforming two coefficients into two pairs of random variables, one random variable in each pair having substantially equal energy as one random variable in the other pair. The method further includes quantizing each of the pairs of random variables and entropy coding each quantized random variable separately creating an encoded bitstreams. The encoded bitstreams are received by a decoder which first determines which channels of the communication system are working. The encoded bitstream is entropy decoded, inversed quantized and inversed transformed. An inverse transform performs three different transformations depending upon which channels are working, i.e., whether the first, second or both channels are working.

Abstract: A central office line unit (COLU) for a pulse code modulation (PCM) upstream and downstream system in a universal digital loop carrier (UDLC) includes a hybrid circuit for transmitting/receiving an analog signal to/from a switch. An analog-to-digital converter is provided for receiving the analog signal from the hybrid circuit and converting the analog signal to a converted digital signal. A digital transmission circuit transmits/receives a digital signal to/from a remote terminal. A quantizer is provided for evaluating and processing the converted digital signal so that only valid states of the converted digital signal are transmitted to the digital transmission circuit for transmission to the remote terminal. A receiver is used for receiving the digital signal from the digital transmission circuit and for evaluating and processing the digital signal so that only valid states of the digital signal are outputted from the receiver.

Abstract: An image processing apparatus includes a converter, a quantizer, a transfer speed recognizer, a transfer data converter and an interface. The converter reads an image of a subject to convert it into an electric signal before outputting it. The quantizer outputs a quantized electric signal as an image signal while quantizing the electric signal output from the converter. The transfer speed recognizer detects a transfer speed of the image signal output to an external part. The transfer data quantity converter converts a data quantity of the quantized image signal from the quantizer in accordance with the transfer speed detected by ther transfer speed recognizer. The interface outputs the image signal outputted from the transfer data quantity converter.

Abstract: A first transceiver transmits a set of test levels to a second transceiver as a signal through a communication channel as encoded samples and subjected to one or more of a plurality of line encoding algorithms. An information channel is superimposed in the signal transmitted through the communication channel. The second transceiver determines line encoding with, and conversion between, the companding laws present in the communication channel based on the received set of test signals. The set of test levels are signals having levels determined based on the difference between the normalized amplitude, vertex, or energy curves for the types of companding laws, with or without accounting for other sources of network distortion. Encoded samples representing the transmitted test levels are reconstructed by the second transceiver in accordance with the one or more detected line encoding algorithms, the encoded samples for each of the set of test levels packed into a corresponding sample cell.

Abstract: A decoder in a communication system using channel optimized vector quantization and including an encoder stores active encoder centroids ci corresponding to active indices i, an active index being defined as an index that has a predetermined source probability pi>0 of being selected by the encoder for transmission to the decoder, source probabilities pi and the bit error rate epsilon to dynamically estimate a decoded vector using a sub-optimal algorithm in which only the most significant contributions are considered.

Abstract: A method for tracing an optimal path by employing a Trellis-based adaptive quantizer can accelerate quantization path tracing and simplify computation thereof, by preventing the quantization path tracing after an turning point of distortion in the Trellis-based adaptive quantizer and after an optimal quantization level to non-zero at a branch positioned from a zero node to a non-zero node. The conventional Trellis-based adaptive quantizer selects the optimal path by tracing and examining all the paths, and thus computation is complicated. In addition, a high speed quantization algorithm is difficult to perform.

Abstract: The present invention provides an apparatus for performing inverse quantization for multiple decoding standards, where the functional operations that comprise the inverse quantizer are modularly implemented and can be selectably performed. Each operation can be represented via a table entry in an associated memory area, with the functional operation being performed via reference to that table entry. Functional operations can be bypassed as needed if inverse quantization does not need to be performed on a set of data. Certain other processing operations can be performed between steps as needed to accommodate different coding standards. Macroblock data can be read from and written back to a common storage area, or a direct path is provided for writing the data directly to a subsequent inverse transform device.

Abstract: An improved ADPCM encoding and decoding apparatus for compressing and de-compressing a differential signal between an input digital signal and a predicted value of said digitized input in accordance with adaptive differential pulse code modulation is described. The apparatus includes a prediction unit for receiving the previous differential signal and performs the prediction in accordance with one of a plurality of different algorithms which is selected by referring to the previous differential signal.

Abstract: An apparatus for encoding and decoding key data and key value data of a coordinate interpolator and a recording medium, on which a bitstream, into which a coordinate interpolator is encoded, is written, are provided. The bitstream includes key data encoding/decoding information, into which key data and information necessary to decode the key data are encoded, and key value data encoding/decoding information, into which key value data and information necessary to decode the key value data are encoded.

Abstract: A narrow-band bandpass filter is implemented in a field programmable gate array (FPGA). An analog-to-digital converter quantizes an input analog signal with a high degree of precision to produce input data samples. A sigma-delta modulator re-quantizes the samples with a substantially lower degree of precision. The re-quantized samples are passed through a bandpass, lowpass, or highpass, finite impulse response (FIR) filter which operates at the lower degree of precision. The reduced degree of precision enables a substantial reduction in the number of resources required to implement the narrow-band bandpass, lowpass, or highpass filter in the FPGA. The modulator includes a predictor filter which has a center frequency coinciding with that of the FIR filter, and redistributes noise such that it is lowest within the passband of the FIR filter. The narrow-band filter design can be adapted to incorporate a single or multi-rate decimator configuration.

Abstract: A time domain signal is converted into a frequency domain signal, and an encoded bit stream is provided. A bit stream decomposer decodes bit stream information, and a storage unit temporary stores the information. In accordance with the bit stream information, a spectral expander expands a frequency spectrum quantized inverse by in an inverse quantizer up to an integer multiple of a sampling frequency of the bit stream. A frequency-time domain converter converts the frequency spectrum into a time domain signal. Thereby, harmonics can precisely be implemented with a small amount of processing, and the band can be expanded with less distortion.

Abstract: A DPCM operation which can reduce the size of differential data and a method and an apparatus for encoding data using the DPCM operation are provided. A method for generating differential data includes generating differential data by performing a DPCM operation on quantized data and generating predicted differential data by performing a predicted DPCM operation on the quantized data, generating circular-quantized differential data and circular-quantized predicted differential data by performing a circular quantization operation on the differential data and the predicted differential data so as to reduce their ranges, and selecting one of the circular-quantized differential data and the circular-quantized predicted differential data depending on their magnitudes.

Abstract: An initialization procedure for a digital modem system treats the presence of ADPCM as if it were a digital impairment such that the modem system can utilize effective compensation techniques to address the ADPCM. The modem system initially determines whether the current communication channel is a fully digital channel. Next, the modem system determines whether the channel includes any ADPCM elements. If ADPCM is detected, then a digital impairment learning routine is performed to obtain the ADPCM compression characteristics and data rate. The digital impairment learning routine may use a single probing sequence to obtain the ADPCM characteristics while identifying any concurrent digital impairments such as RBS, digital pads, and encoding law conversions. Once the digital channel is characterized, the modem system may condition its transmitters and receivers in an appropriate manner to obtain an increased data rate.

Abstract: A transceiver includes a receiver and a transmitter. The receiver includes an analog-to-digital conversion device for converting a received analog signal to digital form, and the transmitter includes a digital-to-analog conversion device for converting a digital signal into analog form for transmission. A selector selects the resolutions of the conversion devices. The resolution of the analog-to-digital conversion device is selected based on a received signal quality, e.g., the signal-to-noise ratio or the signal-to interference ratio. The resolution of the digital-to-analog conversion device is selected based on a crest factor of the transmitted signal, the crest factor depending, e.g., on the modulation format of the signal being transmitted. The higher the crest factor, the higher the resolution selected.

Abstract: A quantizer adapted for use with a delta-sigma analog-to-digital converter. The quantizer includes first and second comparators adapted to compare an input analog signal to a threshold and provide a digital output in response thereto. First and second thresholds are provided to the first and second comparators respectively. In accordance with the present teachings, a mechanism is provided for changing the thresholds to minimize conversion errors. While the mechanism for changing the thresholds may be implemented with resistive and/or capacitive ladders, in the illustrative embodiment, digital-to-analog converters are utilized. The DACs are driven by error shaping logic. The inventive quantizer allows for an improved delta-sigma analog-to-digital converter design which combines an ADC and a DAC. The DAC reconstructs the analog equivalent of the digital output of the ADC. The ADC is a flash converter consisting of one comparator per threshold.

Abstract: A basic transcoder, that decodes an encoded data stream and re-encodes it, may be used for locally modifying data in said stream. Said modification is carried out by defining a predicted data stream on the basis of a given modifying data stream and adding to the decoded stream—between the decoding and re-encoding parts of the transcoder—the difference between the modifying data stream and the predicted one. In an improved implementation, the modifying data stream is preprocessed so that it may be obtained in the decoded data stream a local substitution of said modifying data to the decoded ones.

Abstract: Analog-to-digital converter for converting an analog input signal which is present at a signal input (2a, 2b) and has a specific frequency bandwidth, into an offset-free digital output signal, having a subtracting amplifier (5), which subtracts an analog actuating signal from the analog input signal in order to generate an analog difference signal and amplifies the analog difference signal generated, an analog-to-digital converter circuit (18) having a high clock rate for converting the amplified analog difference signal into the digital output signal, a digital clamping circuit (24) for digital low-pass filtering of the digital output signal, and having a digital-to-analog converter circuit (49) for converting the digital output signal filtered by the clamping circuit (24) into the analog actuating signal.

Abstract: Described is a method of compressing an analogue signal, e.g. a voice signal, the signal function being continuously sampled, quantized and encoded into data words, the difference between each two successive data words determined and each difference value quantized and encoded.

Abstract: A data stream (DS) comprises a time multiplex of coded data (D) and control data (C). The data stream (DS) may be, for example, of the MPEG type representing a sequence of pictures. The coded data (D) is transcoded (T) so as to obtain transcoded data (DT) which differs in size from the coded data (D). The control data (C) is adapted for the transcoded data (DT) so as to obtain adapted control data (CA) which does not substantially differ in size from the control data (C). The transcoded data (DT) and the adapted control data (CA) are written into a transcoder output buffer (TOB) and read from the transcoder output buffer (TOB) so as to obtain a transcoded data stream (DST). This allows an efficient use of a transmission channel via which the transcoded data stream (DST) is to be transmitted and, consequently, it allows a satisfactory transcoding quality.

Abstract: A multi-carrier transmission system. A received multi-carrier signal is sampled and digitized before FFT processing. Multi-carrier signals consist of many narrow band carrier waves which convey data via a wide band channel. The amplitude distribution of the sum of all the individual carriers is Gaussian. This means that high amplitudes occur with low probability. At the present time, analog to digital converters have a limited dynamic range. It is therefore normal practice to provide a compromise between cutting and quantization noise. The adverse affects of a course quantization have to be balanced between signal distortions caused by the loss of the low probability high amplitude signals.

Abstract: A broadband communication system (60), such as a cable television system, includes a forward path for transmitting information from headend equipment to subscribers and a reverse path for transmitting information from the subscribers to the headend equipment. The reverse path includes a transmitting station (65) that receives a first analog signal, converts the first analog signal to a first digital signal having a first number of bits, encodes the first digital signal to generate a second digital signal having a second number of bits less than the first number of bits, then optically transmits the second digital signal. A receiving station (70), also located in the reverse path, receives the second digital signal, decodes the second digital signal to generate a third digital signal having a third number of bits greater than the second number of bits, then converts the third digital signal to a second analog signal that approximates the first analog signal.

Abstract: A method of lattice-quantizing an eight-long data point to minimize storage requirements by acquiring the data point, multiplying each coordinate of the data point by {square root over (2)} to form an inflated data point, rounding each coordinate of the rounded and inflated data point to the nearest integer, modulo-two reducing each coordinate of the rounded and inflated data point to form an initial codeword, multiplying a parity-check matrix of an eight-bit Extended Hamming Code by the result of the last step to form a syndrome, correcting any single-bit errors and double-bit errors, if any, in the initial codeword and the rounded and inflated data point, transforming the coordinate system of the initial codeword to an extended quadratic residue form, creating a signal packet, and transmitting the signal packet to a receiver.

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 high speed decoder for recovering a digital data stream from an analog signal transmitted to said decoder via an analog local loop connected to said decoder. The decoder includes an interface to said local loop. The interface produces an input signal in response to the analog signal. An inverse filter is coupled to the interface. The inverse filter provides a compensated signal in response to the input signal. A converter is coupled to the inverse filter. The converter operates to convert the compensated signal into a sequence of codewords, in which each codeword in the sequence of codewords is associated with a codeword utilized by a digital telephone network. In addition, a decoding method for high speed data transfer over a connection that includes an analog subscriber loop. In a processing environment that includes a processor coupled to at least one memory structure by a bus, the decoding method includes receiving a signal from the analog subscriber loop.

Abstract: An encoding apparatus includes a quantized spectral sequence generation section for generating a quantized spectral sequence by quantizing an audio signal with a predetermined quantization precision, and a circulating code vector quantization section for outputting a spectral sequence code containing circulating position identification information indicating how much a reference spectral sequence is circulated to obtain a circulant quantized spectral sequence which is most similar to the quantized spectral sequence.