205 results about "Channel equalizer" patented technology

A system for monitoring the output of an adaptive channel equalizer in order to determine if convergence has been achieved. A slicer samples data from the equalizer during a predetermined period. The output data from the slicer is forwarded to a microprocessor in order to apply a test standard to the slicer data. For example, if one of every possible transmitted symbol is detected by the microprocessor, convergence is assumed to have occurred. If the test criterion is not met, a reset signal is sent to the equalizer.

A digital broadcast system and method of processing data are disclosed. A channel equalizer includes a frequency domain converter receiving a known data sequence, when the known data sequence is periodically inserted and transmitted in general data, and converting the received data to frequency domain data, a CIR estimator using the data being received during a known data section and known data generated by a receiving system, so as to estimate a CIR, a CIR calculator interpolating or extrapolating the CIR estimated by the CIR estimator in accordance with characteristics of the general data being received, a coefficient calculator converting the CIR being outputted from the CIR calculator to a frequency domain CIR and calculating and outputting an equalization coefficient, and a distortion compensator multiplying the equalization coefficient calculated by the coefficient calculator with the data converted to frequency domain data by the frequency domain converter, thereby compensating channel distortion.

A DTV receiver includes a tuner, a demodulator, a channel equalizer, a sequence detector, and a burst controller. The tuner receives a DTV signal having main data and at least one burst of enhanced data. The demodulator demodulates the DTV signal by performing carrier and time recovery and the channel equalizer equalizes the demodulated signal. The sequence detector detects one or more known data sequences from any one of the received signal and the demodulated signal. The demodulator and the channel equalizer use the detected known data sequences when performing the carrier and timing recover and the channel-equalization, respectively. Lastly, the burst controller supplies power to the tuner, the demodulator, the channel equalizer, and the data detector only during a burst time for each burst of enhanced data for efficient power consumption.

A DTV receiver includes a tuner, an information detector, a demodulator, and a channel equalizer. The tuner receives a broadcast signal including valid data in which a known data sequence is periodically repeated. The information detector detects location information of the known data sequence and a coarse frequency offset value of the broadcast signal. The demodulator demodulates the broadcast signal by estimating a fine frequency offset value using the detected location information and by compensating a frequency offset of the broadcast signal using the course and fine frequency offset values. Finally, the channel equalizer compensates channel distortion of the demodulated signal using the detected location information.

A method for carrying out channel equalization in a radio receiver wherein an impulse response is estimated, noise power is determined by estimating a co-variance matrix of the noise contained in a received signal before prefiltering, and tap coefficients of prefilters and an equalizer are calculated. The method comprises determining the noise power after prefiltering by estimating a noise covariance matrix, after which input signals of the channel equalizer are weighted by weighting coefficients obtained from the noise covariance estimation.

A method and apparatus for data communication in an oil well environment, wherein the method comprises detecting an acoustic signal transmitted along an acoustic channel, the acoustic signal being distorted from transmission through the acoustic channel, generating a transmitted data signal in response to the acoustic signal, inputting the transmitted data signal to an adaptive equalizer and adaptively equalizing the transmitted data signal to produce an equalized data signal related to the transmitted data signal by a mathematical function. The detecting step may include positioning an acoustic receiver in a communication unit along the acoustic channel. The communication unit may be positioned downhole and the adaptive equalizer may be positioned remotely relative to the communication unit or may be placed in the communication unit. The adaptive equalizer may be a frequency domain filter, a neural net adaptive equalizer or a nonlinear recurrent neural net equalizer. The acoustic signal may comprise a plurality of discrete transmissions which may be a training sequence for training the adaptive equalizer and may comprise a first discrete transmission transmitted repeatedly.The method of data communication in an oil well environment may comprise the steps of transmitting an acoustic signal from a first location along an acoustic channel, detecting the acoustic signal at a second location along the acoustic channel, generating a transmitted data signal in response to the acoustic signal, inputting the transmitted data signal to an adaptive equalizer and adaptively equalizing the transmitted data signal to produce an equalized data signal related to the transmitted data signal by a mathematical function. The transmitting step may further comprise positioning an acoustic transmitter in a first communication unit along the acoustic channel downhole or elsewhere. The method may further comprise acquiring data, generating an original data signal in response to the acquired data and inputting the original data signal to the acoustic transmitter. The acoustic signal may comprise a series of acoustic training signals for training the adaptive equalizer. The acoustic training signals may be transmitted at a predetermined time. A stored training signal may include a series of stored training data signals corresponding to the series of acoustic training signals. At least a portion of the stored training signals may be cross-correlated to the transmitted data signal. The acoustic signal may comprise a notification signal for notifying the adaptive equalizer of a training session.

A transmitting system, a receiving system, and a method of processing broadcast signals are disclosed. The receiving system includes a tuner, a channel equalizer, a storage unit, an inner decoder, a deinterleaver, an outer decoder, and an interleaver. The tuner receives a broadcast signal including a data group. The channel equalizer channel-equalizes the broadcast signal. The storage unit stores mobile service data included in the channel-equalized broadcast signal, and repeatedly outputs the stored mobile service data for a predetermined number of turbo decoding iterations. The inner decoder matches the mobile service data being outputted from the storage unit with mobile service data being outer-decoded and fed-back and inner-decodes the matched mobile service data. The deinterleaver deinterleaves the inner-decoded mobile service data in block units. The outer decoder outer-decodes the deinterleaved mobile service data. The interleaver interleaves the outer-decoded mobile service data in block units and feeding-back the interleaved mobile service data to the inner decoder.

A channel equalizer includes a first transformer, an estimator, an average calculator, a second transformer, a coefficient calculator, a compensator, and a third transformer. The first transformer converts normal data into frequency domain data, where a known data sequence is periodically repeated in the normal data. The estimator estimates channel impulse responses (CIR) during known data intervals adjacent to each normal data block. The average calculator calculates an average value of the CIRs. The second transformer converts the average value into frequency domain data. The coefficient calculator calculates equalization coefficients using the average value, and the compensator compensates channel distortion of each normal data block using the coefficients. The third transformer converts the compensated data block into time domain data.

A receiving system and a method of processing broadcast signals in the receiving system are disclosed. The receiving system includes a tuner, a known sequence detector, a carrier recovery unit, a baseband processor, and a channel equalizer. The tuner receives a broadcast signal of a passband including a data group. Herein, the data group comprises mobile service data, a plurality of known data sequences, and signaling data. The known sequence detector estimates an initial frequency offset and detects a position of each known data sequence based on the known data sequence having the first data pattern. The carrier recovery unit acquires an initial frequency synchronization using the initial frequency offset estimated by the known sequence detector and estimates a residual frequency offset based upon the known data sequences having the second data pattern so as to perform carrier recovery. The baseband processor performs complex multiplication between the received broadcast signal and an output of the carrier recovery unit, thereby converting the passband broadcast signal to a baseband broadcast signal.

A receiving system and a method of processing broadcast signals in the receiving system are disclosed. The receiving system includes a tuner, a known sequence detector, a carrier recovery unit, and a channel equalizer. The tuner receives a broadcast signal including a data group. Herein, the data group comprises mobile service data, a plurality of known data sequences, and signaling data. One of the plurality of known data sequences comprises a first M symbol sequence and a second M symbol sequence each having a first data pattern. The known sequence detector estimates an initial frequency offset and detects position information of each known data sequence based on the known data sequence having the first data pattern. The carrier recovery unit acquires initial frequency synchronization and performs carrier recovery from the broadcast signal based on the initial frequency offset estimated by the known sequence detector. The channel equalizer performs channel equalization on the broadcast signal based upon the position information of each known data sequence.

A channel equalizer includes an overlap unit, an estimator, a calculator, a compensator, and a save unit. The overlap unit overlaps a group of data packets in a broadcast signal. The group data packets include a head, a body, and a tail, and a known data sequence is periodically included in the body. The estimator estimates a CIR of each data region the body using the known data sequence, and it further estimates CIRs of data regions in the head or tail using the CIRs obtained for the data regions in the body. The calculator calculates equalization coefficients based on the CIRs estimated by the estimator, and the compensator compensates channel distortion of the overlapped data using the equalization coefficients. The save unit saves the compensated data.

A channel equalizer includes a first transformer, an estimator, an average calculator, a second transformer, a coefficient calculator, a compensator, and a third transformer. The first transformer converts normal data into frequency domain data, where a known data sequence is periodically repeated in the normal data. The estimator estimates channel impulse responses (CIR) during known data intervals adjacent to each normal data block. The average calculator calculates an average value of the CIRs. The second transformer converts the average value into frequency domain data. The coefficient calculator calculates equalization coefficients using the average value, and the compensator compensates channel distortion of each normal data block using the coefficients. The third transformer converts the compensated data block into time domain data.

A receiver (e.g., for a 10 G fiber communications link) includes an interleaved ADC coupled to a multi-channel equalizer that can provide different equalization for different ADC channels within the interleaved ADC. That is, the multi-channel equalizer can compensate for channel-dependent impairments. In one approach, the multi-channel equalizer is a feedforward equalizer (FFE) coupled to a Viterbi decoder, for example a sliding block Viterbi decoder (SBVD); and the FFE and / or the channel estimator for the Viterbi decoder are adapted using the LMS algorithm.

The invention provides a neural network equalization method used for an indoor visible light communication system, and belongs to the visible light wireless communication technology field. The method includes the steps: utilizing a ceiling bounce model to calculate a VLC channel impulse response, carrying out photoelectric conversion for a visible light power signal received by a receiving end, and sending a sequence to a neutral network channel equalizer after amplification sampling; utilizing a heredity algorithm to optimize initialization weights and thresholds among neurons, establishing a neural network for training, and minimizing an error function; and judging an output, restoring the sent sequence, and finally achieving an equalization purpose. According to the scheme, interference among codes is obvious minimized, an error rate is reduced, the communication quality is further improved, a transmission rate that the system can reach is increased, the training time is shortened, and the system complexity is reduced.

A system includes a time-interleaved device. An equalizer effectively can apply different equalization to different interleaved channels. For convenience, these equalizers will be referred to as multi-channel equalizers. In one aspect, an apparatus includes an interleaved device having M interleaved channels, and a multi-channel equalizer coupled to the interleaved device. The multi-channel equalizer is capable of applying a different equalization to different interleaved channels, thus compensating for channel-dependent impairments.

A receiver (e.g., for a 10 G fiber communications link) includes an interleaved ADC coupled to a multi-channel equalizer that can provide different equalization for different ADC channels within the interleaved ADC. That is, the multi-channel equalizer can compensate for channel-dependent impairments. In one approach, the multi-channel equalizer is a feedforward equalizer (FFE) coupled to a Viterbi decoder, for example a sliding block Viterbi decoder (SBVD); and the FFE and / or the channel estimator for the Viterbi decoder are adapted using the LMS algorithm.

A digital receiving system, and a method of processing data are disclosed. The digital receiving system includes a receiving unit, a known sequence detector, and a channel equalizer. The receiving unit receives a broadcast signal including mobile service data and main service data. The known sequence detector detects known data linearly inserted in a data group. The channel equalizer performs channel-equalizing on the received mobile service data using the detected known data.

A DVB-T receiver includes a channel equalizer, a metric assignment and demapping circuit, a Viterbi decoder and an outer Reed-Solomon decoder. The metric assignment and demapping circuit includes a soft-decision quantising arrangement which provides confidence values for the Viterbi decoder. The quantising arrangement receives a control input from channel state indication (CSI) measurement circuitry.A further channel state indication is obtained on a symbol-by-symbol basis. This is compared an average obtained over a few symbols, to detect impulsive interference, and applied as part of the control for the soft-decision quantiser.A signal derived from the further channel state indication is also applied to the erasures input of the Reed-Solomon decoder.

Embodiments of the present invention beneficially provide an ultrasound communication system and methods of ultrasound communication for diagnostics and prognostics of structures. For example, ultrasound transmitters are connected to a metal or composite structure and modulated to produce Lamb waves that travel to an ultrasound receiver. The ultrasound transmitters can use frequency-hopped signals to digitally encode transducer information among different transmitters. The transmitters can be operated asynchronously. The receiver can use a channel equalizer to reduce the effects of signal multipath and a decoder to decode the transducer information from the ultrasound transmitters.

A transmitting system, a receiving system, and a method for processing a broadcast signal are disclosed. The receiving system comprises a tuner, a channel equalizer, a turbo decoder, a demultiplexer, a first error correction decoder, a block deinterleaver, and a second error correction decoder. The tuner receives a broadcast signal including a data group. The data group comprises mobile service data, regularly spaced known data sequences, and signaling data. The turbo decoder performs turbo decoding for the signaling data included in the channel equalized broadcast signal in the channel equalizer. The block deinterleaver performs block deinterleaving for the turbo-decoded FIC data in a block unit of TNoG (the number of all data groups assigned to one subframe)×51 bytes.

Embodiments of the present invention beneficially provide an ultrasound communication system and methods of ultrasound communication for diagnostics and prognostics of structures. For example, ultrasound transmitters are connected to a metal or composite structure and modulated to produce Lamb waves that travel to an ultrasound receiver. The ultrasound transmitters can use frequency-hopped signals to digitally encode transducer information among different transmitters. The transmitters can be operated asynchronously. The receiver can use a channel equalizer to reduce the effects of signal multipath and a decoder to decode the transducer information from the ultrasound transmitters.

A real / complex dual combination channel equalizer is provided, which is capable of minimizing the complexity of a channel equalizer while maintaining the performance of a real and complex mode. The real / complex dual combination channel equalizer includes a combination of elements for inputting real data and imaginary data to a channel select unit, outputting data selected by the channel select unit, yielding real filter output data and imaginary filter output data by multiplying tap coefficients to the outputted data and performing operations, selecting data among the yielded data, outputting a final data of the real filter by subtracting the value outputted from a real decision orientation filter unit from the selected data, outputting real / complex decision data and an error by the outputted data, and renewing the tap coefficient by the data outputted from the channel select unit and the error.

In a channel equalizer applicable to a digital television receiver, a forward filter and a backward filter perform filtering to an input signal and a predetermined signal. A Viterbi decoder corrects errors during a transmission procedure in a blind mode. A training symbol storing block stores training symbols. An output signal of the Viterbi decoder and symbols are provided to the backward filter in accordance with a blind mode or a training mode. A Kalman gain is calculated in a Kalman gain calculating block and an error signal is calculated by comparing an equalized signal, symbols, and the output signal of the Viterbi decoder with one another. A tap coefficient is updated by using the calculated error signal and the Kalman gain.

The invention provides a multi-channel correcting method for ultra wide-band synthetic aperture radar. The method is applied to a multi-channel ultra wide-band synthetic aperture radar / ground moving target indication (UWB SAR / GMTI) system under an hour wide-band width product linear frequency modulation signal system. The technical scheme disclosed by the invention comprises the following steps of: 1, constructing a matched filter system function by using a spectrum correcting technology; 2, correcting an ideal receiving channel to acquire a reference channel; 3, constructing a channel equalizer for each receiving channel; and 4, completing inconsistency correction of the channels. According to the multi-channel correcting method disclosed by the invention, by combining the spectrum correcting technology and inserting the channel equalizer into each receiving channel, frequency property mismatch is corrected, inconsistency correction of the channels is completed, and the pulse compression performance of hour wide-band width product linear frequency modulation signals is effectively improved.

The invention discloses a coding orthogonal frequency division multiplexing wireless signal receiving and processing device and a processing method thereof. The device comprises a receiving synchronizer, a channel equalizer and a decoder. The receiving synchronizer comprises a frame detection module, a time domain decimal frequency offset rectifying module, a sign timing rectifying module, a frequency rectifying module, a Fourier transform module, an integer frequency offset estimation module, a pilot frequency extraction module, a frequency domain decimal frequency offset estimation module, a sign timing offset estimation module, an inherent spurious frequency offset tracking module and a sampling frequency offset rectifying module. The receiving synchronizer comprehensively takes the effects of carrier synchronization offset, carrier phase offset, sampling interval offset, sampling timing offset and orthogonal frequency division multiplexing (OFDM) sign timing offset on OFDM signal demodulation into consideration to design a receiving synchronization algorithm from the three aspects of carrier synchronization, sign timing synchronization and sampling synchronization. The coding orthogonal frequency division multiplexing wireless signal receiving and processing device further has the advantages of being high in video definition, small in transmission delay, strong in interference resistance, high in reliability and the like. The invention further discloses the processing method of the device.

The invention relates to a method and a system for receiving digital broadcasting signals in frequency modulation (FM) broadcast bands. The method comprises the following steps of: receiving digital / analog (D / A) mixed signals x (t); preliminarily separating to acquire preliminarily recovered analog FM signals x0FM (t) and digital FM signals d0 (t); performing first level pilot frequency-based iterative separation on the signals to acquire digital and analog FM signals after the first level iterative separation; and performing second level iterative separation by means of pilot frequency and internal codes, wherein the digital FM signals after the iterative separation acquire digital audio signals and data signals through channel decoding, and the analog FM signals acquire analog audio signals through demodulation and D / A conversion. A digital FM signal demodulation decoder of the system comprises a preliminary FM separator, an iterative FM separator, and a synchronization recovery and channel equalizer and a decoding module, and the iterative offset separation of the analog master FM from digital signals is realized. According to the method and the system, the mixed D / A signals overlapped by the same channel are separated, the mutual interference of the signals is eliminated, and the FM band digital broadcasting system can be realized.

A radio frequency (RF) transceiver includes an RF transmitter that generates a transmit signal to a remote communication device based on outbound data. An RF receiver generates inbound data based on a received signal from the remote communication device. The RF receiver includes a channel equalizer and generates post equalization performance data. A beamform controller generates a plurality of beamforming weights to adjust a beamforming pattern of an antenna array based on the post equalization performance data.

Blind channel equalization methods, receivers and systems incorporating the same for use in a multiple-input, multiple-output, (MIMO) wireless communication system are described. Signal equalization is achieved by devising a characteristic system convolution matrix and algebraically operating on said convolution matrix by equalizing functions generated from second order statistics of the received signals. Such equalization is done with an aim to removing or suppressing inter-symbol interference elements from the received signals to enable satisfactory signal recovery. The described methods, systems and receivers, have the benefits of retaining the speed and processing power efficiency of equalization algorithms based on second order statistics while substantially insensitive to the accuracy of channel order estimates.

A receiving system and a method of processing broadcast signal are disclosed herein. The receiving system includes a signal receiving unit, a known sequence detector, a channel equalizer, a block decoder, and an error correction unit. The signal receiving unit receives a broadcast signal, which includes mobile service data and a data group including multiple known data sequences. The known sequence detector detects the multiple of known data sequences from the broadcast signal. The channel equalizer repeats a process of updating equalization coefficients and filtering as many times as a pre-determined number of iterations, based upon the detected known data sequences, so as to converge the equalization coefficient. Then, the channel equalizer interpolates or extrapolates using the converged equalization coefficients, thereby channel-equalizing the mobile service data. The block decoder performs turbo-decoding in block units on the channel-equalized mobile service data. And, the error correction unit performs error correction decoding on the decoded mobile service data, thereby correcting an error occurred in the mobile service data.