Abstract: A compound chirp is provided in a received signal to permit a receiver to synchronize to the received signal. The compound chirp has temporally overlapping up frequency and down frequency components.

Abstract: The present invention is a method and apparatus to remove the adverse effects due to the imbalance between in-phase (I) and quadrature (Q) channels for I-Q demodulators and modulators in multi-carrier systems. A first balancer generates a first balancing signal from a first signal of a first index corresponding to a first frequency. A first combiner combines the first balancing signal and a second signal of a second index corresponding to a second frequency. The second frequency is symmetrical to the first frequency with respect to a center frequency in a multi-carrier composite signal. The first combiner generates a first balanced signal corresponding to the second frequency.

Abstract: To be able to detect a plurality of correlations in a spread code cycle when receiving CDMA type signals spread with a prescribed spread code and performing correlation detections using a matched filters. A synchronicity detection device which detects a timing of a prescribed spread code already known included in a reception signal is equipped with a correlation coefficient generation means 130 which divides and generates a replica code of a spread code of a prescribed length while a phase advances at each interval of a prescribed width and matched filters 103 and 104 which perform detection of correlation values of reception signals and replica codes generated by the correlation coefficient generation means at each interval of a prescribed width.

Abstract: In a coding system for asymmetric digital subscriber line (ADSL) communications, a method of encoding a sequence of information bits is provided comprising the steps of dividing the information bits into encoding bits and parallel bits; encoding the encoding bits to produce encoded bits; mapping the encoded bits and the parallel bits into first and second pulse amplitude modulation (PAM) signals; and generating a quadrature amplitude modulation (QAM) signal from these first and second PAM signals. This method overcomes the decoder complexity that would otherwise be required due to the large QAM constellations involved for ADSL communications.

Abstract: A clock recovery circuit (10) for a superconductor system that enables the phase of a system clock to be instantaneously reset without any pulse interaction. The clock recovery circuit (10) includes a Josephson transmission line oscillator loop (14) of length 2T, where T is equal to one clock period. First and second data inputs (16, 18) are for injecting a data pulse onto the oscillator loop (14). A pulse generator (24) is for injecting an initial clock pulse onto the oscillator loop (14) that is output as periodic clock signals. An output tap (12) is for outputting the data pulse from one of the first and second data inputs (16, 18), and the periodic clock signals in the absence of the data pulse. When the data pulse is input on one of first and second output taps (32, 34), the clock phase is instantaneously reset.

Abstract: An apparatus for detecting a frame transmission period in a CDMA mobile communication system supporting a discontinuous transmission mode. A first frame detector performs primary frame detection by calculating a signal-to-interference ratio (SIR) using traffic symbol energy, pilot symbol energy and noise energy measured for a predetermined time period, and comparing the SIR with a predetermined frame detection threshold value. A decoder calculates a symbol error rate (SER) by decoding symbols received for the predetermined time period. A second frame detector selects an SER threshold value according to frame detection information from the first frame detector, and compares the selected SER threshold value with the SER to determine whether a frame has been transmitted.

Abstract: The invention relates to a method of coding and of decoding a digital data stream coded by spatio-temporal combinations, in multiple transmission and reception. On transmission, the initial stream (IDS) is subjected to an outer coding (A), a blockwise interleaving (B), a demultiplexing (C) over a plurality of pathways, to an inner coding ?m on each pathway, then transmitted on a plurality (?) of distinct antennas forming a space-diversity array. On reception, the coded symbol streams transmitted are observed (F) by means of a number ? of reception antennas which is independent of the number of transmission antennas, the observed coded symbol streams { MSDS r } r = 1 r = ? are subjected to a process of turbo-detection by equalization and joint decoding (G), deinterleaving (H), outer decoding (I), interleaving (J), so as to generate an a priori information item (api) on the coded bits, which is reinjected (K) into the turbo-detection process.

Abstract: A system and method of the present invention revives a catastrophic code used for channel coding data. A data receiving circuit receives a digital input data sequence to be coded with a code having a distance spectrum containing an infinite component that corresponds to a finite hamming weight such that the code may cause catastrophic error propagation. The circuit is operative for periodically inserting known symbols into the digital input data sequence. An encoder, such as a convolutional encoder, is operatively connected to the data receiving circuit and encodes the digital input data sequence.

Abstract: A method and system for modulating data onto a carrier signal in a plurality of channels, each of the channels having a channel bandwidth, can be created for use in any two-way satellite communication system or other wireless communication application where frequency hopping with or without Doppler compensation is desired. The system preferably includes a digital modulator that outputs a modulated baseband signal, an intermediate frequency modulator that receives the modulated baseband signal and outputs an intermediate frequency signal derived from the modulated baseband signal, a frequency synthesizing system that outputs a synthesized intermediate frequency signal to the intermediate frequency modulator, and a circuit (numerically controlled oscillator) connected to the digital modulator which provides a signal to the digital modulator.

Abstract: Techniques are provided for synthesizing a long coherent I and Q correlation integral at a particular frequency by synthetically combining a sequence of shorter correlation integrals at the same or different frequency. Techniques are also provided for acquiring a carrier-modulated signal with an unknown shift of the carrier frequency, and possibly some additional unknown signal parameters. These techniques involve synthesizing coherent correlation sums at a fine frequency resolution, using coherent correlation sums that are calculated at a coarse frequency resolution. This approach allows for coherent processing of the received signal over an arbitrarily long time interval, while avoiding the excessive computational requirements of traditional methods.

Abstract: A variable rate modulator maps an input data sequence DIN into a quadrature modulated output data sequence DOUT and then converts the DOUT data sequence into an analog output signal AOUT. The data rate at which elements of the DIN sequence are supplied as input to modulator 10 may vary, but the sample rate fsamp at which elements of the DOUT sequence are produce remains constant. In producing the DOUT sequence, the modulator employs an interpolating root Nyquist filter having time-varying filter coefficients to provide both low pass filtration and interpolation.

Abstract: A method and apparatus are provided that allows a single spatially directed broadcast burst to serve users throughout a base station sector. In one embodiment, the invention includes sending a first segment of a broadcast channel burst using a first set of unchanging spatial parameters from an array of antenna elements, and sending a second segment of the broadcast channel burst using a second set of different unchanging spatial parameters from the array of antenna elements.

Abstract: The invention relates to a transmission system and a processing system for video signals relating to TV programs, for the purpose of constructing a mosaic of TV programs displayed on a user's television set, allowing him to select a particular TV program quickly and in a relevant manner via a menu.

Abstract: A wave detecting section of a receiver has a first wavelet transformer involving a plurality of wavelet filters orthogonal to each other for performing a wavelet transform on received waveform data, a Hilbert transformer for performing a Hilbert transform on the received waveform data, a second wavelet transformer having the same configuration as that of the first wavelet transformer for performing a wavelet transform on outputs from the Hilbert transformer, a code converter for inverting the codes of outputs in odd-numbered places among outputs from the second wavelet transformer, a level converter for correcting fluctuations of outputs from the code converter attributable to a ripple of the Hilbert transformer, and a complex data generator for generating complex data, by defining outputs of the first wavelet transformer as in-phase components of the complex information and outputs from the level converter as orthogonal components of the complex information.

Abstract: In the line terminating device, which is provided for transmitting and receiving narrowband low-frequency voice signals and broadband data signals at a higher frequency, the analog reception path is subdivided into two separate analog paths (32, 33) for voice and data using a balance filter (49), which is used for data signal echo cancellation. In the transmission direction, the voice signal path and the data signal path are separated in the digital part by means of digital filters (43, 45). The invention is used for voice and data signal separation in xDSL methods, for example, ADSL.Lite.

Abstract: A method and apparatus are provided that allows a receiver to tune to a broadcast burst through phase and amplitude discontinuities. In one embodiment, the invention includes sending a first segment of a broadcast channel burst using a first set of signal parameters from an array of antenna elements of a broadcast channel radio, sending a second segment of the broadcast channel burst after sending the first segment, the second segment being sent using a second set of signal parameters from the broadcast channel radio array, and sending a third segment of the broadcast channel burst after sending the second segment, the third segment being sent using the first set of signal parameters from the broadcast channel radio array.

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: Transmissions on the dedicated channel are encoded using a set of paramaters that are picked from a large selection of potential parameters. If the remote station does not know the particular set of parameters that were used by a base station, then the remote station would have to attempt to decode the transmission using every set of parameters, until the transmission is decoded correctly. This is an inefficient methodology. Hence, transmission format information is typically transmitted on a broadcast channel so that a remote station could receive the transmission format information. However, the broadcast channel has reliability problems. New methods and apparatus are presented to allow a base station to determine an overlapping set of Walsh code sequences that can be used to send the transmission format information on the dedicated channel, rather than a broadcast channel. Using the overlapping set allows the remote station to decode the information.

Abstract: A Baseband receiver including a CIR estimate block, gain, phase and timing loops, a CMF, a single-carrier processor and a multi-carrier processor. The CIR estimate block generates an impulse response signal based on a receive signal that is a single-carrier signal or a single-carrier segment of a mixed carrier signal. The single-carrier segment has a spectrum that approximates a multi-carrier spectrum. The gain, phase and timing loops adjust gain, phase, frequency and timing to provide an adjusted receive signal. The CMF filters the adjusted receive signal according to the impulse response signal. The single-carrier processor processes the adjusted and filtered receive signal to resolve a single-carrier segment of a mixed carrier signal. The single-carrier processor detects a mixed carrier mode indication in a single-carrier segment and asserts a start indication. The multi-carrier processor processes a multi-carrier segment of a mixed carrier signal in response to assertion of the start indication.

Abstract: An apparatus is described comprising: a decoder which decodes a plurality of data streams, the decoder having a state associated with each of the data streams; and state restoration logic to restore the decoder's state upon switching from decoding one data stream to another data stream.