Abstract: An equalizer generates an equalized sample from a plurality of received samples in which a forward equalizer filters a received sample to generate a FE output. A feedback equalizer filters the equalized sample to generate a FBE output. An integrator adds the FE and FBE outputs to generate the equalized sample. The feedback equalizer comprises first and a second sub-filters. The first sub-filter has a first bit-width capability to generate a first FBE output from the equalized sample. The second sub-filter has a second bit-width capability to generate a second FBE output from the equalized sample. The first bit-width is higher than the second bit-width, and the first and second FBE outputs jointly organize the FBE output.

Abstract: An adaptive equalizer comprises: a forward equalizer (FE) receiving a symbol stream to generate an FE output; a decision feedback equalizer (DFE) receiving a decision symbol stream to generate a DFE output; a first adder, coupled to the forward equalizer and the decision feedback equalizer, adding the FE and DFE outputs to generate an equalizer output; a first trellis decoder, coupled to the first adder, receiving the equalizer output to generate a trellis decoded stream by a trellis decoding process; and a compensator for compensating the equalizer output according to the decision symbol stream, the trellis decoded stream, and a coefficient vector stored in the decision feedback equalizer, to generate a compensated equalizer output.

Abstract: An exemplary embodiment of an adaptive equalizer is provided, receiving symbols to generate an equalizer output. The adaptive equalizer comprises a plurality of tap cells, a coefficient updater, a plurality of multiplexers, a controller and an integrator. Each tap cell generates a filter value from a tap data value and a coefficient. The coefficient updater provides a coefficient vector comprising a plurality of coefficients updated recursively. Each multiplexer is coupled to a corresponding tap cell and the coefficient updater, switching between a normal mode and an estimation mode. The controller coupled to the multiplexers controls mode switching of each multiplexer based on each corresponding coefficient. The integrator coupled to the tap cells collects the filter values to generate an equalizer output.

Abstract: Apparatuses and methods for scanning channels in a television signal receiver. The apparatuses generally include a first acquisition circuit, a second acquisition circuit, and a controller. The first acquisition circuit is generally configured to determine, during a first time period, whether a selected radio frequency channel has a first format and to produce a first acquisition indicator in response thereto. The second acquisition circuit is generally configured to determine, during a second time period overlapping the first time period, whether the selected radio frequency channel has a second format and to produce a second acquisition indicator in response thereto. The controller is generally configured to scan a plurality of radio frequency channels by operating the first acquisition circuit and the second acquisition circuit for each one of the plurality of radio frequency channels. Embodiments advantageously provides for faster scanning and acquisition of television signals in a mixed-format (e.g.

Abstract: In a channel estimation method, an input signal is received. The input signal is then sliced to obtain a sliced signal. The multiplication of the input signal and the ith delayed sliced signal are accumulated to obtain a cross-correlation value. The energy of the sliced signal is measured. The ith channel parameter of a channel response is estimated according to the division of the cross-correlation value by the energy of the sliced signal. A channel estimator performing channel estimation is also provided.

Abstract: Methods and television receivers for rejecting a co-channel interference signal from a first digital signal. A first digital signal is delayed to output a first delayed signal. In this method, an synthesized interference signal is generated based on the first digital signal. The synthesized interference signal is subtracted from the first delayed digital signal and produces a second digital signal. The second digital signal is equalized to output an equalized signal based on a first decision signal. The equalized signal is decoded to output the first decision signal. The equalized signal is delayed to output a second delayed signal. A compensation signal is generated based on the first decision signal. The compensation signal is subtracted from the delayed second signal and produces a fifth digital signal serving as an output signal.

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: Methods and television receivers for rejecting a co-channel interference signal from a first digital signal. A first digital signal is delayed to output a first delayed signal. In this method, an synthesized interference signal is generated based on the first digital signal. The synthesized interference signal is subtracted from the first delayed digital signal and produces a second digital signal. The second digital signal is equalized to output an equalized signal based on a first decision signal. The equalized signal is decoded to output the first decision signal. The equalized signal is delayed to output a second delayed signal. A compensation signal is generated based on the first decision signal. The compensation signal is subtracted from the delayed second signal and produces a fifth digital signal serving as an output signal.

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 exemplary embodiment of an adaptive equalizer is provided, receiving symbols to generate an equalizer output. The adaptive equalizer comprises a plurality of tap cells, a coefficient updater, a plurality of multiplexers, a controller and an integrator. Each tap cell generates a filter value from a tap data value and a coefficient. The coefficient updater provides a coefficient vector comprising a plurality of coefficients updated recursively. . Each multiplexer is coupled to a corresponding tap cell and the coefficient updater, switching between a normal mode and an estimation mode. The controller coupled to the multiplexers controls mode switching of each multiplexer based on each corresponding coefficient. The integrator coupled to the tap cells collects the filter values to generate an equalizer output.

Abstract: A method for adaptively tuning an equalizer is disclosed. The method includes utilizing the equalizer to process an input signal and accordingly generate an output signal, determining whether the equalizer has converged, and adjusting an equalizer step size of the equalizer according to a result of the step of determining whether the equalizer has converged.

Abstract: Methods and system removing co-channel interference from a digital signal. In this method, the digital signal interfered by an interference signal is received, wherein the interference signal comprises consecutive sections, each of which contains N symbols. An average signal is generated by calculating an average over the received digital signal at periodic time instants (n?k*N), wherein N is a constant, n denotes the present time instant and k is a non-negative integer. A first estimated interference signal is generated by filtering the average signal, and the first estimated interference signal is subtracted from the received digital signal and output a first signal.

Abstract: An adaptive equalizer comprises: a forward equalizer (FE) receiving a symbol stream to generate an FE output; a decision feedback equalizer (DFE) receiving a decision symbol stream to generate a DFE output; a first adder, coupled to the forward equalizer and the decision feedback equalizer, adding the FE and DFE outputs to generate an equalizer output; a first trellis decoder, coupled to the first adder, receiving the equalizer output to generate a trellis decoded stream by a trellis decoding process; and a compensator for compensating the equalizer output according to the decision symbol stream, the trellis decoded stream, and a coefficient vector stored in the decision feedback equalizer, to generate a compensated equalizer output.

Abstract: An apparatus performs burst noise detection and then reduce the interference of the burst noise by controlling an operation of an adaptive apparatus, such as an equalizer. It includes: an adaptive apparatus having multiple coefficients, processing incoming signals according to these coefficients, and employing an error estimator to update the coefficients; a burst noise detector used to detect a burst noise; and an ON/OFF switching unit used to stop the error estimator from updating the coefficients when the burst noise is detected.

Abstract: Methods and television receivers for rejecting a co-channel interference signal from a first digital signal. A first digital signal is delayed to output a first delayed signal. In this method, an synthesized interference signal is generated based on the first digital signal. The synthesized interference signal is subtracted from the first delayed digital signal and produces a second digital signal. The second digital signal is equalized to output an equalized signal based on a first decision signal. The equalized signal is decoded to output the first decision signal. The equalized signal is delayed to output a second delayed signal. A compensation signal is generated based on the first decision signal. The compensation signal is subtracted from the delayed second signal and produces a fifth digital signal serving as an output signal.

Abstract: A method for noise enhancement reduction in an adaptive equalizer comprising a plurality of filter tap cells having respective coefficients and tap data values. First, a step size is determined based on a norm value of an ith parameter of an estimated channel response. The coefficient of the ith filter tap cell is updated based on the step size, an error signal, and the tap data value of the ith filter tap cell. The step size is determined by a piecewise function of the norm value of the ith parameter. The piecewise function is a non-decreasing convex function or a non-decreasing stepwise function. An adaptive equalizer performing the described method is also provided.

Abstract: In a channel estimation method, an input signal is received. The input signal is then sliced to obtain a sliced signal. The multiplication of the input signal and the ith delayed sliced signal are accumulated to obtain a cross-correlation value. The energy of the sliced signal is measured. The ith channel parameter of a channel response is estimated according to the division of the cross-correlation value by the energy of the sliced signal. A channel estimator performing channel estimation is also provided.

Abstract: An error propagation reduction method is provided, for an equalizer comprising a forward equalizer and a decision feedback equalizer. First, an input signal is equalized to generate an equalized signal. The equalized signal is quantized to generate a quantized signal. The equalized signal is error decoded to generate a decoded signal. A value is calculated by linear combining the equalized signal, the quantized signal, and the decoded signal with weighting coefficients adaptable according to the channel quality. The value is used to set a register whose associated decision feedback equalizer coefficient has maximal magnitude. An apparatus performing the error propagation reduction is also provided.

Abstract: A method for noise enhancement reduction in an adaptive equalizer comprising a plurality of filter tap cells having respective coefficients and tap data values. First, a step size is determined based on a norm value of an ith parameter of an estimated channel response. The coefficient of the ith filter tap cell is updated based on the step size, an error signal, and the tap data value of the ith filter tap cell. The step size is a non-decreasing stepwise function of the norm value of the ithparameter of the estimated channel response. An adaptive equalizer performing the described method is also provided.

Abstract: An echo indicator generation method, generating an echo indicator to indicate echo levels in a channel response of a transmission channel based on an input signal. The input signal comprises segment sync patterns repeating at intervals transmitted over the transmission channel. The input signal is filtered with a match filter having a filter response matched to the segment sync pattern to output a first signal. Thereafter, the first signal is periodically averaged to output a second signal. An echo indicator representing the echo levels of the transmission channel response is generated based on the second signal. Thus the echo level of the channel response is obtained.