834 results about "Equalizer" patented technology

Systems and methods for optimizing speaker performance. The system includes a self-contained speaker unit that includes a speaker, an amplifier coupled to the speaker, and a processor coupled to the amplifier. The processor receives a first sound signal from a receiver and a second sound signal from a microphone, processes the first sound signal based on a plurality of parameters, outputs the processed sound signal to the speaker, and generates a video signal based on the second sound signal. A wireless remote control allows a user to manipulate the parameters. The processor generates a test sound signal and outputs it to the receiver. The receiver processes the test sound signal and returns it to the processor for output through the speaker. The video signal includes a graphical user interface having a frequency response graph of the second sound signal and an eight band equalizer.

This optical receiving device for discriminating and recovering a data signal, which results from converting an optical signal input through a dispersion equalizer into an electrical signal and amplifying it to a pre-determined amplitude, by using a clock and data recovery circuit for discriminating a data signal at the decision point controlled to achieve the optimum position controls the dispersion characteristics of a dispersion equalizer so that the error count in the recovered data signal by using a clock and data recovery circuit will be minimized by controlling the eye pattern of the data signal which has been amplified to a pre-determined amplitude.

In described embodiments, a transceiver includes a baud-rate clock and data recovery (CDR) module with an eye sampler, and an adaptation module for adaptively setting parameters of various circuit elements, such as timing, equalizer and gain elements. Data sampling clock phase of the CDR module is set for sampling at, for example, near the center of a data eye detected by the eye sampler, and the phase of data error sampling latch(es) is skewed by the CDR module with respect to the phase of the data sampling latch. Since the error signal driving the timing adaptation contains the information of the pulse response that the CDR module encounters, the phase of timing error sampling latch(es) of the CDR module is skewed based on maintaining a relative equivalence of input pulse response residual pre-cursor and residual post-cursor with respect to the timing error sampling clock phase.

A baseband signal converter device for an impulse radio receiver combines multiple converter circuits and an RF amplifier in a single integrated circuit package. Each converter circuit includes an integrator circuit that integrates a portion of each RF pulse during a sampling period triggered by a timing pulse generator. The integrator capacitor is isolated by a pair of Schottky diodes connected to a pair of load resistors. A current equalizer circuit equalizes the current flowing through the load resistors when the integrator is not sampling. Current steering logic transfers load current between the diodes and a constant bias circuit depending on whether a sampling pulse is present.

Techniques and instrumentalities to improve ISI and ICI cancellation in reception of modulated symbols by selectively decoding subsymbols of such modulated symbol before they can be completely decided or perceived as well as use of decoded symbol/subsymbol information in the feedback equalization process are disclosed. In particular, a decoder and corresponding method are disclosed which includes a feedback equalizer capable of receiving a modulated signal including a symbol defined by a first number of chips, along with a subsymbol processor to generate a subsymbol waveform upon receipt of a second number, less than the first number, of chips of such symbol and provide the subsymbol waveform to the feedback equalizer in order to equalize the modulated signal using the subsymbol waveform. Other disclosed aspects including techniques and instrumentalities for improving reception performance when symbols encoded by different modulation schemes are encountered, as well as feedback equalization for Barker encoded symbols present in the received signal.

A method for uplink burst equalization in broad wide access system, using the form of combining pre-training and burst equalization, that is, before transmitting user data, training the equalizer, then starting transmitting user data, in which, the equalizer uses decision user data as reference to track the changed wireless channel; if the change of channel exceeds the tracking region of equalizer, for example, the error rate exceeds threshold 1 but doesn't exceed threshold 2, the burst equalization will be performed; if the channel change exceeds the equalization region of equalizer, for example, the error rate exceeds threshold 2, the training will be performed again. By using the form of combining pre-training and burst equalization, setting different thresholds for handoff, the present invention greatly prolongs the intervals of subsequent pre-training process, thereby reducing the times of pre-training and increasing the effective bandwidth; By introducing burst equalization process, the present invention also decreases the requirement of system on operation occasion (for example, the static channel or the interval of bursts should be short), thereby increasing the application occasions of product.

A single-axis receiver processing, for example, complex vestigial sideband modulated signals with an equalizer with forward and feedback filters. Forward and feedback filters have parameters that are initialized and adapted to steady state operation. Adaptive equalization employs linear predictive filtering and error term generation based on various cost criteria. Adaptive equalization includes recursive update of parameters for forward and feedback filtering as operation changes between linear and decision-feedback equalization of either single or multi-channel signals. An adaptive, linear predictive filter generates real-valued parameters that are employed to set the parameters of the feedback filter. In an initialization mode, filter parameters are set via a linear prediction filter to approximate the inverse of the channel's impulse/frequency response and a constant modulus error term for adaptation of the filter parameters. In an acquisition mode, equalization is as linear equalization with a constant modulus error term, and possibly other error terms in combination, for adaptation of the filter parameters. In a tracking mode, equalization is as decision feedback equalization with decision-directed error terms for adaptation of the filter parameters. For some equalizer configurations, feedback filtering is applied to real-valued decisions corresponding to complex-valued received data, and includes real-part extraction of the error term employed for recursive update of filtering parameters. Where a training sequence is available to the receiver, initial parameters for forward filtering are estimated by correlation of the received signal with the training sequence.

Disclosed is a LMMSE receiver that restores orthogonality of spreading codes in the downlink channel for a spread spectrum signal received over N receive antennas. The FFT-based chip equalizer tap solver reduces the direct matrix inverse of the prior art to the inverse of some submatrices of size N×N with the dimension of the receive antennas, and most efficiently reduces matrix inverses to no larger than 2×2. Complexity is further reduced over a conventional Fast Fourier Transform approach by Hermitian optimization to the inverse of submatrices and tree pruning. For a receiver with N=4 or N=2 with double oversampling, the resulting 4×4 matrices are partitioned into 2×2 block sub-matrices, inverted, and rebuilt into a 4×4 matrix. Common computations are found and repeated computations are eliminated to improve efficiency. Generic design architecture is derived from the special design blocks to eliminate redundancies in complex operations. Optimally, the architecture is parallel and pipelined.

An equalizer is applied to a signal to be transmitted via at least one multiple input, multiple output (MIMO) channel or received via at least one MIMO channel using a matrix equalizer computational device. Channel state information (CSI) is received, and the CSI is provided to the matrix equalizer computational device when the matrix equalizer computational device is not needed for matrix equalization. One or more transmit beamsteering codewords are selected from a transmit beamsteering codebook based on output generated by the matrix equalizer computational device in response to the CSI provided to the matrix equalizer computational device.

An apparatus including a first circuit and a second circuit. The first circuit may be configured to generate an equalized signal in response to an input signal and an equalizer parameter signal. The equalizer parameter signal generally causes a cancellation of pre-cursor inter-symbol interference from a plurality of symbols in the input signal. The second circuit may be configured to generate (i) the equalizer parameter signal, (ii) a control signal and (iii) a data output signal in response to the equalized signal. The control signal generally causes an adjustment of the equalizer parameter signal. The adjustment of the equalizer parameter signal generally causes a decrease in the pre-cursor inter-symbol interference from the symbols.

Described embodiments provide a method of adjusting configurable parameters of at least one linear equalizer in a communication system. A transmitting device applies an input signal to a receiver. The at least one linear equalizer equalizes the input signal. A sampler generates one or more sampled values of the input signal. A data detector digitizes the sampled values of the input signal. At least one error detection module generates an error signal based on one or more of a plurality of sampled values of the input signal and a target value. An adaptation module determines a gradient signal based on a comparison of one or more of the plurality of sampled values of the input signal and one or more of the plurality of values of the error signal. The adaptation module adjusts a transfer function of the at least one linear equalizer based on the determined gradient signal.

An apparatus including a first circuit and a second circuit. The first circuit may be configured to determine values for a predefined metric for a plurality of tap positions within a range covered by a decision feedback equalizer (DFE). The values for a number of taps may be determined in parallel. The second circuit may be configured to set one or more floating taps of the DFE to tap positions based upon the values of the predefined metric. The floating taps in the decision feedback equalizer may be selected adaptively.