Abstract: A decision directed flicker noise canceller for reducing flicker noise in a modulated input signal according to an embodiment of the present invention includes a decision circuit, a conversion circuit, first and second adders and a filter. The decision circuit provides signal decisions based on the input signal. The conversion circuit provides selected signal values based on the signal decisions. The first adder subtracts the selected signal values from signals based on the input signal to provide a flicker noise estimate. The filter receives and filters the flicker noise estimate and the second adder subtracts the filtered flicker noise estimate from the input signal and provides a corrected input signal. In a feedback configuration, the second adder is located in a feedback position before the decision circuit in the signal processing path. In a feed-forward configuration, the second adder is located in a feed-forward position after the decision circuit.

Abstract: A system and method of estimating radio frequency (RF) background noise in a radio receiver system comprises determining a total receiver front-end noise based on a noise equivalent receiver bandwidth; estimating external noise associated with the radio receiver system; determining internal noise associated with the radio receiver system from a known noise value; combining the external noise with the internal noise; determining an absolute external (RF) background noise floor associated with the radio receiver system; estimating an out of band noise contribution based on radio receiver selectivity and known received noise levels of out of band sources; and generating a (RF) noise estimate in the radio receiver system based on the above steps. The invention utilizes the (RF) noise estimate to form a (RF) receiver signal to noise ratio enabling an estimate performance of (RF) radio links in the radio receiver system operating in a benign and hostile (RF) environment.

Abstract: Systems, methods, and apparatus for reducing dynamic range requirements of a power amplifier in a wireless device are provided. An exemplary method may include modulating a symbol stream to generate a modulated waveform. The exemplary method may further include generating at least one pulse having a peak aligned with an anticipated position of a peak or a null corresponding to the modulated waveform, where the anticipated position of the a peak or the null corresponding to modulated waveform may be determined by detecting a transition in a phase or an amplitude of the modulated waveform.

Abstract: A method includes performing a search method to determine a pair of receiver path correction signals, performing the search method to determine a pair of transmitter path correction signals, and using the pairs of receiver path and transmitter path correction signals to suppress a carrier signal. An apparatus includes a first pair of summers, an upconverter circuit coupled to the first pair of summers, a multiplexer coupled to the upconverter circuit, to a ground, and to an RF front end, a downconverter circuit coupled to the multiplexer, a second pair of summers coupled to the downconverter circuit, and a correction circuit coupled to the first and second pairs of summers.

Abstract: A radio channel simulator configured to read radio channel data describing a radio channel and user data including at least one user signal, and to simulate the radio channel using a FIR filter comprising one or more FIR blocks for filtering the user data read based on radio channel data in connection with the simulation. The radio channel simulator is configured to transfer at least one FIR block at a delay level depicting a radio channel delay during simulation.

Abstract: Canceling interference in a multi-input multi-output (MIMO) system is accomplished with a plurality of interference cancellers. Each interference canceller outputs an interference-cancelled received version of its corresponding transmitted signal. An estimate of the transmitted signals from all transmitting antennae is used in each interference canceller. Each estimate is multiplied by a channel coefficient matrix, which can be derived from the communication of known pilot symbols, and the resulting products of each estimate and the channel coefficient matrix are subtracted from the received signals, resulting in a corresponding difference. Each corresponding difference may be multiplied by a filter weight vector. The received signal is decoded based upon the resulting products If a predetermined interrupt criteria is not met, then the decoded signal is used in the preparation of the estimate for a subsequent interference cancellation iteration.

Abstract: A power control unit (500) for a power control system in a mobile communication system, the power control unit (500) comprising an inner power control loop element (503, 507), which generates a transmit power control command (504), and an outer power control loop element (516) connected to the inner power control loop element (503, 507), the outer power control loop element (516) being configured for providing a target value (506) to the inner power control loop element (503, 507). The outer power control loop element (516) comprises a soft information estimator (509) connected to at least one outer loop regulator (501, 502), wherein the soft information estimator (509) is configured to provide a soft information estimate (510) to the at least one outer loop regulator (503).

Abstract: A method for protecting Security Accounts Manager (SAM) files within a Windows® operating system is disclosed. A SAM file encryption key is generated by encrypting a SAM file via a syskey utility provided within the Windows® operating system. The SAM file encryption key is then stored in a virtual floppy disk by selecting an option to store SAM file encryption key to a floppy disk under the syskey utility. A blob is generated by performing a Trusted Platform Module (TPM) Seal command against the SAM file encryption key along with a value stored in a Performance Control Register and a TPM Storage Root Key. The blob is stored in a non-volatile storage area of a computer.

Abstract: A system and method for adjusting the power control target for a spread-spectrum communication system is disclosed. A preferred embodiment comprises correcting the power control target based upon the estimated slope of the SIR versus quality of service (QoS) curve under current operating conditions. By using the estimated slope of the current SIR versus QoS curve, the power control target converges to the desired value most quickly, and the SIR target overshoot or undershoot is maximally avoided, and the power rise is minimized, thereby reducing power requirements and signal dropouts. The invention finds application, for example, in personal communication devices such as cellular telephones and may be implemented using a digital signal processor (DSP).

Abstract: Predistortion effective for a power amplifier with the memory effect is provided. An A/D converter digitizes a signal voltage value after quadrature modulation, and the result is supplied to a subtractor. A lookup table outputs voltage value data in accordance with an output of the subtractor. The output of the lookup table is used as address data for accessing respective lookup tables. The lookup tables output an accumulation adding value derived from multiplying, by impulse responses, the signal voltage value after quadrature modulation and supplies it to the subtractor. The voltage value data outputted from the lookup table is converted by a D/A converter to output it as a predistortion signal for amplitude component for the power amplifier.

Abstract: An I/Q modulator used for processing an I/Q signal to obtain a predistorted output signal. The I/Q signal has an I component and a Q component, and comprises a predistorter for predistorting, with a predistortion signal, a carrier signal, which comprises a first subcomponent and a second subcomponent that is substantially orthogonal to the first subcomponent, to obtain first and second predistorted subcomponents of the carrier signal. The predistortion signal depends on the I and Q components. A first multiplier multiples the I component by the first predistorted subcomponent to obtain a multiplied I component. A second multiplier multiples the Q component by the second predistorted subcomponent to obtain a multiplied Q component. An adder adds the multiplied I component and the negative multiplied Q component to obtain the predistorted output signal. Thus, a simplification of the I/Q modulator and a reduction in the number of necessary multipliers is achieved.

Abstract: A signal is predistorted by producing a set of sample values, each of at least a subset of which is dependent on (i) at least one of a plurality of past time spaced input samples and (ii) a current time spaced input sample, and independent of any other time spaced input sample, and combining the sample values to produce the predistorted signal. Predistortion circuitry for generating the predistorted signal may be implemented using multiple predistortion core circuits, with each of the predistortion core circuits receiving a data input and an index input associated with a particular input sample and generating a corresponding data output. The data outputs of the predistortion core circuits correspond generally to sample values. The predistortion circuitry may also include at least one memory finite impulse response (FIR) filter which processes one or more input samples in conjunction with the production of the sample values.

Abstract: An adaptive broadband post-distortion receiver for wireless digital communications improves performance of a wireless digital communications system. The improved performance of the system includes improved linear AM-AM and AM-PM responses approaching saturation. Indeed, the proposed adaptive broadband post-distortion receiver has an effect on attributes such as bit error rate and transmitter power efficiency and, in turn, on modulation and bandwidth. The adaptive broadband post-distortion receiver is configured with an adaptively controlled IF post-distorter located at the IF stage of the receiver. The placement of the distortion canceling function in the IF section of the receiver lends itself to broadband applications. The post-distorter is configured to cancels the distortion produced by the transmitter and receiver as it is adaptively controlled using bit error rate calculations. The distortion canceling utilizes bit error rate information that is otherwise available in the receiver.

Abstract: The present invention relates to a signal modulation loop for the multi-mode mobile communication. The adaptive up-conversion modulation loop is applied in the multi-mode mobile communication, and is used for signal integration for the communication system comprising the second generation communication system, the global system for mobile communication (GSM), and the third generation communication system, the wideband code division multiple access (WCDMA), so as to achieve the object of multi-mode communication by using a single modulation loop.

Abstract: This invention provides a technique and an architecture to pre-distort signals such that when the signals are amplified, the non-linear distortions of the amplifier chain are opposite that of the pre-distortion thus yielding a distortion free or nearly distortion free signal at the output of the amplifier chain. This invention provides for a low power application by using a LUT predistortion that is performed on a composite real signal (I and Q combined) such that the size of the LUTs required is reduced to a very small size. In this invention, the I and Q input signals are digitally modulation with quadrature digital sinusoidal signals and then combined to create the real composite signal at a digital IF. The real signal is then pre-distorted to compensate for AM/AM distortion first and then for AM/PM distortion. The pre-distorted signal is then digitally decomposed back in to I and Q samples for conversion to analog and up conversion to RF.

Abstract: A circuit provides a reduced harmonic content output signal OUTA and/or OUTB that is modulated according to an input signal 231. The circuit has an oscillator circuit 210 and a harmonic rejection mixer (HRM) 230. The oscillator circuit 210 includes at least one “circuit portion” (FIG. 2A) configured to receive first and second orthogonal oscillator input signals (two of I, I?, Q, Q?) having respective first and second phases, and to provide an arbitrarily large number of oscillator output signals (?M) having respective mutually distinct phases that are interpolated between the first and second phases. Harmonic rejection mixer 230 is configured to use the input signal to modulate a combination of the oscillator output signals, the oscillator output signals being respectively weighted so as to provide an emulated sinusoidal signal constituting the reduced harmonic content output signal.

Abstract: A method and an apparatus for serial data communication employs a data transmission process which transmits data from one control unit to the another control unit and at the same time checks a reception confirmation signal on each number of the data by transmitting a clock signal, and a data reception process which receives the data on the one control unit from the other control unit and checks a transmission confirmation signal on the each number of the data by transmitting the clock signal. The apparatus comprises a first and a second control unit, four serial buses for performing serial data communication between the both control units, two pull-up operation units for continuing control voltage of the serial buses at a certain level, and a control voltage matching unit for continuing voltage equilibrium condition.

Abstract: An I/Q modulator processes a time-discrete I/Q signal comprising an I component and a Q component. The I/Q signal is based on a sampling frequency which is equal to four times a carrier frequency of a carrier signal onto which the I/Q signal is modulated. A predistorter of the modulator predistort the I and components with a predistortion signal, which depends on the I and Q components, so as to form a predistorted I component and, in temporal alternation therewith, a predistorted Q components. An adjuster of the modulator adjusts the signs of the predistorted I and Q components so that two temporally successive predistorted components have a first sign and two additional successive predistorted components, which follow the first-mentioned components in time, have a second sign which is the inverse of the first sign, so as to produce therefrom an output signal at an output of the modulator.

Abstract: A method and apparatus determines an uncoded bit error rate pb based on a target symbol error rate ?s. The uncoded bit error rate pb is determined based on a weighted series expansion of the target symbol error rate ?s, comprising weights W that are a function of a maximum number of symbol errors that can be corrected t and a number of symbols in an information field K. The maximum number of symbol errors t and the number of symbols in the information field K is selected such that the uncoded bit error rate pb that produces a symbol error rate that is less than or equal to the target symbol error rate ?s is largest.

Abstract: A synchronization establishing apparatus in a spectrum spread communication system, includes a search section that calculates correlation values from a received spectrum spread signal, and calculates power values and power addition values of the power values. Also, the search section selects larger ones of the power addition values to output together with timing data corresponding to the selected larger power addition values. One of the symbols and the power values is corrected in phase based on phase change quantities. A frequency offset estimating section estimates frequency offsets from one of the correlation values and the power values and demodulation timing data and calculates the phase change quantities from the estimated frequency offsets. A demodulation path selecting section selects path timings based on the selected larger power addition values and outputs the demodulation timing data to the frequency offset estimating section.

Abstract: The invention relates to an apparatus, and an associated method, in a communication system that is tolerant to interference. The received signal is divided into a real and an imaginary part, and the noise and interference is modeled as a filtered process. The invention solves the interference problem by utilizing the inherent signal structure.

Abstract: A channel optimization system for use with a communications channel and method of separating and encoding signals associated with the communications channel. In one embodiment, the channel optimization system includes an assorter that receives first and second signals having disparate transmission characteristics and selects one of the first and second signals. The channel optimization system also includes a translator, coupled to the assorter, that encodes the selected one of the first and second signals into a symbol representation as a function of a transmission characteristic associated therewith.

Abstract: A method for generating a premodulation-filtered modulation waveform having a real part and an imaginary part for transmitting octal symbols uses a reduced lookup table. Successive octal symbols, each comprising three information bits, are input to a logic unit. The logic unit forms a first derived bit by combining the first and third information bits and a second derived bit by combining the second and third information bits. The first and second information bits, along with the first and second derived bits, are delayed in respective L-bit shift registers. The bit sequences in the L-bit shift registers are used to determine a corresponding filtered waveform segment for each bit sequence. The waveform segments corresponding to the delayed first information bits and the delayed first derived bits are combined to obtain a segment of said imaginary waveform part.

Abstract: A wireless communication base station system of the present invention includes a wireless key base station, an optical forward base station, and an optical transmitter which connects the wireless key base station and the optical forward base station to each other. An optical signal modulated by a signal component and that modulated by a distortion component are transmitted from the wireless key base station to the optical forward base station. In the optical forward base station, these optical signals are converted to high-frequency electrical signals, and the high-frequency signal consisting of the signal component is amplified. Thereafter, the amplified signal is combined with the high-frequency signal consisting of the distortion component with their phases opposite to each other, so that the distortion component include in the amplified signal is removed.

Abstract: A spread spectrum receiver and method having narrow-band interference rejection of narrow-band jamming signals using digital signal processing frequency domain techniques.

Abstract: The invention relates to a method for implementing a transceiver, in which method radio-frequency signals are transmitted and received with a transceiver for communicating information. A radio-frequency signal received at a receiving stage is subjected to at least a first filtering step, in which a desired receiving signal is separated from the signal with a filter. A signal to be transmitted at a transmission stage is subjected to at least a second filtering step, in which a desired transmission signal is separated from the signal with a filter, to be transmitted. In the method, the same filter is used at least partly in said first and second filtering steps.

Abstract: Systems and methods for sharing a single decoder among data streams originating with multiple sources. Error correction coding techniques are modified to facilitate decoding of data from multiple sources multiplexed in the time domain at the decoder input. A single decoder accommodates multiple sources that have been encoded using disparate code rates. One application is an OFDM point to multipoint system.

Abstract: The present invention includes a method and system for compensating for cross-talk interference in communication systems. The method includes estimation of the interfering signals. Further, the method includes performing a compensation operation on at least one interfering signal.

Abstract: A transmission system having a channel subjected to fading uses an iterative block detection method which includes a multiplication step for multiplying the received blocks via a filter matrix whose elements are written as ρ j * E ⁢   ⁢ ( ρ j 2 ) + N 0 where &rgr;j*, j=1, . . . , n are the conjugate values of the coefficients &rgr;j of the channel, n is the size of the block, E(&rgr;j2) is the expectation &rgr;j2, and No is the variance of the Gaussian noise.

Abstract: Method for predistortion compensation for nonlinear distortion produced by the non-linear power amplifier of the QAM signal at the transmitter side of the direct digital communication channel. The out-of-band signal power is monitored by the existent receiver at the receive side of the direct propagation channel. The nonlinear distortion compensation signal is generated at the receiver/demodulator side of the direct propagation channel and transmitted across the direct propagation channel to an input of a pre-distortion block at the transmitter/modulator side of the direct propagation channel. The nonlinear distortion compensation signal is used to adjust the set of parameters of the pre-distortion block in order to minimize the out-of-band power produced by the non-linear amplifier (NLA).

Abstract: A modulator converts an inputted data to be transmitted into a septenary data, modulates a carrier by the converted data, and transmits the modulated carrier via an antenna. A demodulator demodulates a received data supplied from the antenna into an octonary data, which is converted into a septenary data. According to the structure, a vector representing the modulated carrier is prevented from passing a “O” point when a phase shift of the modulate carrier occurs.

Abstract: A phase correction circuit for a radio communication apparatus includes a variable gain amplifier and phase correction unit. The variable gain amplifier amplifies a transmission/reception signal on the basis of a gain variably set in accordance with a gain signal. The phase correction unit has a phase characteristic opposite to that of the variable gain amplifier, corrects the phase of the transmission/reception signal on the basis of the gain signal supplied to the variable gain amplifier, and cancels a phase change of the signal caused in the variable gain amplifier.

Abstract: A method and offset removing apparatus for removing DC offset from a digital baseband signal value pair included in a set of digital baseband signal value pairs is described. The digital baseband signal value pairs, when plotted on a complex signal space I-Q diagram, lie on a predetermined figure. The I and Q coordinates of the central point of this predetermined figure are determined by a two-dimensional fitting of this figure through a subset of signal value pairs included within the set. These coordinates of this center point are subsequently subtracted from the I and Q coordinates of the digital baseband signal.

Abstract: When reception of a multiplexed wave to be PSK-modulated of BPSK, QPSK, and 8PSK is started, a selector (16A) of a demodulating circuit (1A) reads high-order three bits &Dgr;&phgr;(3) of phase error data corresponding to I and Q symbol streams out of one phase error table (15-1) for BPSK among phase error tables provided for each modulation system and each phase rotation angle. A received-signal-phase rotation angle detecting circuit (8A) detects phase rotation angles of portions corresponding to bits (1) and (0) of a frame-synchronizing signal of a received symbol stream from the &Dgr;&phgr;(3) and the MSB of I symbol stream and outputs the phase rotation angles to a remapper (7) to make the remapper perform absolute phasing.

Abstract: A new class of 16-ary Amplitude and Phase Shift Keying (APSK) coded modulations, called double-ring APSK modulation, based on an amplitude and phase shift keying constellation in which the locations of the digital signals to be encoded are placed on two concentric rings of equally spaced signal points. The APSK constellation parameters are optimised so as to pre-compensate the impact of non-linearities. The new modulation scheme is suited for being used with different coding schemes. It is shown that, for the same coding scheme, pre-distorted double-ring APSK modulation significantly outperforms classical 16-QAM and 16-PSK over a typical satellite channel, due to its intrinsic robustness against the high power amplifier non-linear characteristics. The proposed coded modulation scheme is shown to provide a considerable performance advantage for future satellite multi-media and broadcasting systems.

Abstract: Systems and methods for sharing a single decoder among data streams originating with multiple sources. Error correction coding techniques are modified to facilitate decoding of data from multiple sources multiplexed in the time domain at the decoder input. A single decoder accommodates multiple sources that have been encoded using disparate code rates. One application is an OFDM point to multipoint system.

Abstract: In a cable television (CATV) data communication network, channel throughput and communications robustness are increased in a manner that improves speed of data transmission while maintaining compatibility with existing specifications and equipment. Enhanced throughput can be realized using the return channel of the CATV network. Alternatively, data retransmission and/or diversity techniques can be used to improve throughput.

Abstract: Methods, systems and receiver devices are provided which may reduce the average power of a signal disturbance by whitening the signal disturbance. In one aspect, a finite impulse response filter (FIR) is provided which whitens the signal disturbance by filtering a downsampled received signal using filter coefficients adaptively established using known signal information in each signal burst of the received signal. Alternatively, a noise-whitening equalizer is utilized having a modified metric that whitens the signal disturbance again using coefficients adaptively established using known signal information in each signal burst of the received signal. The noise-whitening equalizer approach further allows the noise-whitening coefficients to be updated by treating symbol estimates from the equalizer as known signal information to generate updated noise-whitening coefficients. A novel receiver containing a modified Euclidean metric equalizer to provide noise-whitening is also provided.

Abstract: A system and method facilitate estimating noise in a received signal. The received signal includes a plurality of data tones. Noise is estimated for a selected subset of data tones for each data burst, such that noise estimates for all data tones can be computed over a plurality of data bursts. As a result of spreading the noise estimates over more than one burst, the overall computations associated with obtaining the noise estimates can be reduced based on the size of the respective subsets. The updated data tone noise estimates further can be employed in subsequent processing, such as in beamforming calculations.

Abstract: A peak to average power ratio in a DS-CDMA transmitter is reduced by applying hard limiting to the signal while it is in digital form and prior to any frequency band filtering. In the case of a complex signal the clipping is done by making an approximation to the magnitude of the complex signal, comparing this to a threshold value and, whenever the magnitude exceeds the threshold, scaling the in-phase and quadrature components by a factor equal to the ratio of the threshold value to the magnitude. The approximation to the magnitude is made by reducing the signal to the first octant of the complex plane, evaluating a plurality of linear functions of the reduced in-phase and quadrature components, and selecting the maximum value.

Abstract: The present invention relates to a method and an apparatus for compensating a signal that has experienced fading distortion in a communication channel. The signal that can be a TDMA (Time Division Multiple Access) signal includes slots that carry data symbols. Non-uniformly spaced pilot symbols are also embedded in the slot structure. The receiver separates the incoming symbols stream in two parts namely a pilot symbols stream and data symbols stream. Since the transmitted pilot symbols are known, an estimate of the channel distortion on the pilot symbols locations can be computed. This estimate is then interpolated to provide an estimate of the fading distortion at the data symbols locations, thus allowing to compensate accurately for the fading distortion in the channel.

Abstract: A system and method for signal peak reduction in a multiple carrier communication system where the individual carriers are produced from input symbols that are filtered to reduce individual carrier bandwidths, offset in frequency, and combined into an output signal. A multiple carrier peak reduction unit is provided which modifies the input carrier symbols so that the combined output signal does not exceed a predetermined peak limit value. The multiple carrier peak reduction unit includes filter predictors that predict the effect of each channel filter on that carriers input symbols by using filter coefficient values corresponding to the impulse response function of each filter. The filter predictor outputs are then phase shifted, in correspondence to frequency offsets provided for in multiple carrier signal generation, and combined to produce a prediction of the combined signal output which is then processed to determine the corrections required to the individual channel symbol inputs.

Abstract: A system and method for signal peak reduction in a spread spectrum communication system of the type including a filter for limiting signal bandwidth of symbols transmitted from the system. A signal peak reduction unit is provided before the filter that includes a filter predictor that predicts the effect of the filter on input symbols by using filter coefficient values corresponding to the filter impulse response function. Input symbols that are predicted to cause the output signal to exceed a predetermined peak limit value are adjusted. Several examples of suitable algorithms for calculating the necessary peak reduction to be applied to the input symbols are disclosed. The peak reduction unit provides adjusted symbols to the filter for processing and communication system output.

Abstract: The present invention relates to a demodulator which receives a signal transmitted via phase modulation or multivalue QAM modulation, and decides transmitted data based on the received signal. The present invention enhances a transmission-line estimate by using tentatively decided data symbols as pilot symbols and in estimating a transmission line without a decrease in accuracy of transmission-line estimate even when an error rate of the tentatively decided data symbols is increased. The demodulator includes a pilot-based transmission-line estimation unit for estimating transmission-line characteristics by using pilot symbols. A tentative-data-decision unit for tentatively deciding data symbols based on the pilot-based transmission-line estimate. A data-based transmission-line estimation unit for estimating the transmission-line characteristics by using the tentatively decided data.

Abstract: An impulse noise detector detects impulse noise in an audio signal by filtering out the audio components of the signal, then comparing an envelope of a filtered signal with a threshold obtained as a moving average of the envelope. Short-duration impulse noise is thereby detected without detecting tone bursts and other fast-rising signals of longer duration. The envelope may be taken directly from the filtered signal, or from a difference signal obtained from a preliminary envelope of the filtered signal, to emphasize impulse noise when distorted audio components leak into the filtered signal.

Abstract: A method for generating an in-phase (I) output signal and a quadrature-phase (Q) output signal from an input signal reduces phase error in the I/Q generator by delaying-and-doubling an input signal to produce a Q output signal and delaying the input signal twice and subtracting the same from the input signal to produce an I output signal. The I/Q generator includes a first 90°-phase delay circuit receiving an input signal and outputting an intermediate Q signal; a second 90°-phase delay circuit receiving the intermediate Q signal and producing an intermediate I signal. It also includes a signal doubler receiving the intermediate Q signal and producing a Q output signal of twice the amplitude of the input signal at a 90° phase angle. Finally, the generator includes a signal differencer receiving the input signal and the intermediate I signal and producing an I output signal of substantially twice the amplitude of the input signal at a 0° phase angle.

Abstract: A receiver restores a transmitted information bit series accurately by performing maximum-likelihood series estimation. The operation of the receiver includes estimating characteristics of a transmission line for each symbol based on the amplitude and phases of pilot symbols which are extracted from reception symbol groups, calculating weighting factors showing the reliability of the transmission line in symbols based on the estimation result and the reception symbol groups, multiplying each symbol of information symbol groups which are extracted from the reception symbol groups by the weighting factors to reflect the transmission-line reliability in symbols, and restoring an information bit series by applying maximum-likelihood series estimation to coded bit groups restored from the information symbol groups on which the reliability is reflected.

Abstract: A communication system (10) includes a transmitter (20) having programmable signals (46, 58, 60, 80) which can be used to adjust transmitter-caused quadrature-phase signal imbalances. A receiver (18) of the system (10) is remotely located from the transmitter (20) and generates a signal quality statistic (102, 112) that is monitored in a slow-tracking feedback loop to formulate commands which indicate how to program the programmable signals (46, 58, 60, 80). This receiver (18) performs its signal quality statistic monitoring while a data stream (36) is being extracted from a received communication signal.

Abstract: The present invention refers to a transmission/reception unit that exchanges data with a remote unit by means of a channel using distributed modulation/demodulation treatment means. The transmission/reception unit includes equalization means (23) to equalize a first signal received from said remote unit and predistortion means to predistort a second signal transmitted to said remote unit. According to the invention, the unit is characterized in that the modulation/demodulation treatment means operate in a non-linear way and the unit includes means (230) to store information that is representative of a non-linear distortion of said modulation/demodulation treatment means and which defines a non-linear reference, and means (233) to adjust coefficients (CO) in the equalization means (23) according to the signal received from the remote unit and said representative information, the mentioned adjusted coefficients being transmitted to said predistortion means.

Abstract: A circuit and method for adaptively calculating a decision error of a digital signal in a digital modulation system.