Abstract: An imbalance compensator includes a phase/filter mismatch correction circuit and a gain mismatch correction circuit. The phase/filter mismatch correction circuit includes an adjustable filter and a processing unit. The adjustable filter is arranged for adjusting a filter coefficient setting according to a first input signal of a first signal branch and a second input signal of a second signal branch, and generating a first compensated signal to the first signal branch according to the filter coefficient setting and the first input signal. The processing unit is arranged for processing the second input signal according to the first compensated signal and generating a second compensated signal to the second signal branch. The gain mismatch correction circuit is arranged for referring to the first and second compensated signals to configure gain compensation, and applying the configured gain compensation to one of the first and second compensated signals.

Abstract: An imbalance compensator includes a phase/filter mismatch correction circuit and a gain mismatch correction circuit. The phase/filter mismatch correction circuit includes an adjustable filter and a processing unit. The adjustable filter is arranged for adjusting a filter coefficient setting according to a first input signal of a first signal branch and a second input signal of a second signal branch, and generating a first compensated signal to the first signal branch according to the filter coefficient setting and the first input signal. The processing unit is arranged for processing the second input signal according to the first compensated signal and generating a second compensated signal to the second signal branch. The gain mismatch correction circuit is arranged for referring to the first and second compensated signals to configure gain compensation, and applying the configured gain compensation to one of the first and second compensated signals.

Abstract: A signal receiver includes a demodulator, a narrow-band interference detector, and a control module, where the demodulator is for performing signal demodulation upon a received communication signal, the narrow-band interference detector is for performing narrow-band interference detection and accordingly generating a detection result, and the control module is for controlling an operation of the demodulator according to the detection result. In addition, a narrow-band interference detector includes an input port and a processing circuit, where the input port is coupled to an equalizer included in a signal receiver for receiving a signal generated from the equalizer, and the processing circuit is coupled to the input port for performing a narrow-band interference detection according to the signal generated from the equalizer, and accordingly generating a detection result.

Abstract: An equalizer. The equalizer, either operated in a blind mode or a decision directed mode, comprises a feed-forward filter, a feedback filter, a decision device, a control circuit, and a multiplexer. The feed-forward filter receives an input signal. The feedback filter filters an equalized signal. The combiner combines the feed-forward filtered signal and the feedback filtered signal. The decision device maps the combined signal to one symbol of a symbol set. The control circuit receives the combined output and generates a slice control signal. The multiplexer selects the combined signal or the mapped signal as the equalized according to the slice control signal when operated in the blind mode.

Abstract: A signal receiver includes a demodulator, a narrow-band interference detector, and a control module, where the demodulator is for performing signal demodulation upon a received communication signal, the narrow-band interference detector is for performing narrow-band interference detection and accordingly generating a detection result, and the control module is for controlling an operation of the demodulator according to the detection result. In addition, a narrow-band interference detector includes an input port and a processing circuit, where the input port is coupled to an equalizer included in a signal receiver for receiving a signal generated from the equalizer, and the processing circuit is coupled to the input port for performing a narrow-band interference detection according to the signal generated from the equalizer, and accordingly generating a detection result.

Abstract: A communication system and a method which can reduce the effect of burst noise. The communication system comprises a controllable oscillator, a mixer, a decision circuit, a comparator, a loop filter, and a controller. The controllable oscillator generates an oscillating signal. The mixer coupled to the controllable receives input data and mixes the input data with the oscillating signal. The decision circuit receives the mixed input data and generates an estimated symbol. The comparator generates a decision error between the estimated symbol and the mixed input data. The loop filter coupled to the controllable oscillator filters the decision error, and generates a filtered decision error, and the controllable oscillator generates the oscillating signal according to the filtered decision error. The controller reduces a bandwidth of the loop filter according to the decision error.

Abstract: An equalization method receiving a received sample to generate an equalizer output. A channel profile is first provided, comprising a main path and a plurality of echoes distributed in time domain. Echoes anterior to the main path are precursors, and echoes posterior to the main path are postcursors. The received sample is filtered with a linear equalizer (LE) comprising a plurality of taps to generate an LE output. A slicer slices the equalizer output to generate a sliced sample. The sliced sample is further sent to a decision feedback equalizer (DFE) comprising a plurality of taps to generate a DFE output. Simultaneously, an equalizer span is determined based on the channel profile. The LE output and the DFE output are combined to generate the equalizer output having the equalizer span. The equalizer span is determined by allocating the position of main tap.

Abstract: A communication receiving system, an equalizer, and a method for mitigating a burst noise effect of a signal are provided. The equalizer is configured to compensate the signal received from a communication channel. The communication receiving system comprises a receiver, the equalizer, and a detection module. The receiver transmits the signal to the equalizer after receiving the signal. The equalizer compensates the signal and adapts its weighting factors by modifying a correction term upon detection of burst noise. Thereby, the burst noise effect of the signal is mitigated, and the probability that the equalizer survives the burst noise condition increases. Thus, the quality of communication systems under burst noise cases may be enhanced under without increasing the complexity of hardware.

Abstract: A communication system and a method which can reduce the effect of burst noise. The communication system comprises a controllable oscillator, a mixer, a decision circuit, a comparator, a loop filter, and a controller. The controllable oscillator generates an oscillating signal. The mixer coupled to the controllable receives input data and mixes the input data with the oscillating signal. The decision circuit receives the mixed input data and generates an estimated symbol. The comparator generates a decision error between the estimated symbol and the mixed input data. The loop filter coupled to the controllable oscillator filters the decision error, and generates a filtered decision error, and the controllable oscillator generates the oscillating signal according to the filtered decision error. The controller reduces a bandwidth of the loop filter according to the decision error.

Abstract: An amplitude-modulation signal reception apparatus is provided. The amplitude-modulation signal receiver apparatus includes a timing recovery module, a symbol phase shift unit, and an equalizer. The carrier recovery module removes a frequency offset and a phase jitter from an amplitude-modulation signal to generate a carrier recovered signal. The timing recovery module estimates a proper re-sampling position to re-sample the carrier-recovered signal. The phase shifter further shifts the signal that is timing recovered and carrier recovered. The equalizer applies equalization to the shifted signal to remove inter-symbol interference from the shifted signal.

Abstract: An equalizer. The equalizer, either operated in a blind mode or a decision directed mode, comprises a feed-forward filter, a feedback filter, a decision device, a control circuit, and a multiplexer. The feed-forward filter receives an input signal. The feedback filter filters an equalized signal. The combiner combines the feed-forward filtered signal and the feedback filtered signal. The decision device maps the combined signal to one symbol of a symbol set. The control circuit receives the combined output and generates a slice control signal. The multiplexer selects the combined signal or the mapped signal as the equalized according to the slice control signal when operated in the blind mode.

Abstract: A method and apparatus for detecting the transmitted mode and guard interval length. The mode detection is adopted by the DVB-T system to increase system flexibility and combat multi-path interference in the transmission environment, of the received OFDM signals by applying the concepts of down-sampling and correlation. The unique combination of down-sampling and correlation method requires far less memory than the traditional correlation methods. By comparing the indicators resulting from output of each correlation module, the transmitted mode and guard interval length are detected with much greater reliability.

Abstract: Decision feedback equalizers and related equalizing method are provided. One proposed decision feedback equalizer includes: a feed-forward filter for filtering an incoming signal to generate a filtered signal; a feedback filter for generating a feedback signal according to a decision signal; an operating device, coupled to the feed-forward filter and the feedback filter, for generating an output signal according to the filtered signal and the feedback signal; a decision device, coupled to the operating device and the feedback filter, for generating the decision signal according to the output signal; and an updating device coupled to the feedback filter for constraining coefficients of predetermined taps of the feedback filter while updating the tap coefficients of the feedback filter; wherein each predetermined tap of the feedback filter corresponds to a tap of the feed-forward filter.

Abstract: An equalization circuit and an equalization method implemented thereby are provided. A received symbol is received to generate a equalizer output. In the equalization circuit, an equalizer performs equalization to the received symbol based on a SNR value of the equalizer output. A SNR estimator coupled to the output of equalizer receives the equalizer output to measure the SNR value. The equalizer equalizes the received symbol by the LMS algorithm in which coefficients are recursively updated by a step size, and the step size is adjusted based on the SNR value.

Abstract: An equalization method receiving a received sample to generate an equalizer output. A channel profile is first provided, comprising a main path and a plurality of echoes distributed in time domain. Echoes anterior to the main path are precursors, and echoes posterior to the main path are postcursors. The received sample is filtered with a linear equalizer (LE) comprising a plurality of taps to generate an LE output. A slicer slices the equalizer output to generate a sliced sample. The sliced sample is further sent to a decision feedback equalizer (DFE) comprising a plurality of taps to generate a DFE output. Simultaneously, an equalizer span is determined based on the channel profile. The LE output and the DFE output are combined to generate the equalizer output having the equalizer span. The equalizer span is determined by allocating the position of main tap.

Abstract: A method of mode detection for OFDM signals. The method comprises the steps of delaying the OFDM signal for a first and second number of samples, multiplying the two delayed signals by coefficient signals, and deriving a sum of the two products, deriving an error signal by subtracting the sum of the two products from the OFDM signal, extracting amplitudes of the coefficient signals, and accordingly deriving step size signals, updating the coefficient signals according to the error signal and step size signals, detecting edges of the amplitudes of the coefficient signals, and determining the guard interval length and transmission mode according to the detected edges.

Abstract: A Quadrature Amplitude Modulation (QAM) receiver is provided to demodulate received symbols into a constellation, and comprises a radio frequency (RF) module, an analog to digital converter (ADC), an auto gain controller (AGC), a digital modulator, a distribution analyzer and a system controller. The RF module receives and demodulates radio signals into received symbols. The ADC coupled to the RF module generates digital signals from the received symbols. The AGC normalizes signal amplitudes in the RF module. The digital demodulator performs synchronization and equalization to decode the digital signals, whereby a constellation is generated. The distribution analyzer coupled to the output of the ADC and the digital demodulator provides a decision grid to analyze the constellation. The system controller is coupled to the distribution analyzer, adjusting the AGC and digital demodulator according to the constellation analysis.

Abstract: An equalization method and device for equalizing the received vestigial sideband (VSB) signal, utilizes segment-sync symbols, Sato directions, erasure slicers, and variable step-sizes. In addition to stop-and-go (SAG) mode, the directions of Sato errors can also be used for speed up the convergence of tap weights of the equalizer. Erasure slicers can mitigate the effect of decision errors as they are passed through the feedback filter. In time-variant environments, variable step-sizes help the equalizer tracking the variations of the channels; in time-invariant environments, variable step-sizes help ease the fluctuations of the steady-state equalizer tap weights, and therefore yield smaller mean-squared-error and better symbol error rate (SER).

Abstract: A method and apparatus for detecting the transmitted mode and guard interval length. The mode detection is adopted by the DVB-T system to increase system flexibility and combat multi-path interference in the transmission environment, of the received OFDM signals by applying the concepts of down-sampling and correlation. The unique combination of down-sampling and correlation method requires far less memory than the traditional correlation methods. By comparing the indicators resulting from output of each correlation module, the transmitted mode and guard interval length are detected with much greater reliability.

Abstract: A method of mode detection for an OFDM signal. The method comprises the steps of a) selecting one of the desired symbol lengths, b) selecting one of the threshold values, c) generating a correlation power signal of the OFDM signal using the selected desired symbol length, d) detecting edges of the correlation power signal using the selected threshold value, e) when the edge detection succeeds, determining the transmission mode and guard interval length by the detected edges, and f) when the edge detection fails, determining whether all the threshold values have been selected, if so, selecting another one of the desired symbol lengths and repeating steps b, c, d, e and f, otherwise, selecting another one of the threshold values and repeating steps c, d, e and f.