Abstract: As disclosed herein, a “super receiver” structure enriches the information provided for decoding modem bits included in a received sequence of symbols. In particular, an equalizer circuit provides joint metrics to a decoder circuit, where the joint metrics advantageously reflect joint bit probabilities. However, the metrics are computed without need for complex joint probability calculations. The decoder circuit “fuses” the joint metrics with corresponding side information, which indicates the likelihood that one or more bits represented by the joint metric take on a particular value. Such fusing biases the soft value estimation for the other bits represented by the joint metric, thus enabling the decoder to operate on refined soft values in its bit decoding operations.

Abstract: A device processes signals from a plurality of signal channels that are received in parallel. A channel processing circuit (12a,b, 14a,b), applies a series of filtering operations selectively to the signal from a first one of the signal channels. A filter management circuit (18) detects a reception condition from reception of a signal in a second one of the signal channels. The filter management circuit (18) controls application of at least a part of said filtering operations to the signal from the first one the signal channels by the channel processing circuit (12a,b, 14a,b), dependent on the detected reception condition. Selected filter operations may be enabled or disabled. Thus, power consumption may be reduced. In an embodiment, the detected reception condition is determined as a by-product of functional reception of another channel. Thus power consumption for the detection of the reception condition is also reduced.

Abstract: A transversal filter circuit comprises a plurality of delay units, a plurality of multiplexers and a plurality of full adders. The plurality of delay units is coupled in series to delay a two-bit input signal. The plurality of multiplexers is coupled to the plurality of delay units in a one-to-one manner, and outputs zero, a data signal, or the inverse of the data signal according to the output signals of the plurality of delay units. The plurality of full adders accumulates the outputs of the plurality of multiplexers and the MSB of the outputs of the plurality of the delay units.

Abstract: A Non-Continuous Orthogonal Frequency Division Multiplexing (NC-OFDM) system may be provided. The NC-OFDM system, including: a sensing unit to determine whether to use at least one frequency band; a band control unit to disable a subcarrier with respect to a frequency band in use as a result of the determination; a pruning determination unit to determine whether a number of points where the subcarrier is disabled is greater than a threshold value; a pruning retrieval unit to retrieve a pruning path generated by the disabling of the subcarrier, when the number of points is greater than the threshold value; and a Fourier transform unit to perform a Fast Fourier transform (FFT) or Inverse FFT (IFFT) by applying the pruning path to the subcarrier.

Abstract: Disclosed is an apparatus including an odd data receiving unit that receives an input signal, an even data receiving unit that also receives the input signal, and a pattern filter. The odd data receiving unit samples a half-rate DFE equalized signal with an odd data timing clock to output data decision data. The even data receiving unit samples the half-rate DFE equalized signal with an even data timing clock having the phase shifted by 180 degrees from the odd data timing clock to output data decision data. The pattern filter selects one of the edge decision data sampled at the odd edge timing and at the even edge timing in response to the value of a data pattern of three consecutive bits obtained from the data decision data sampled at the odd and even data timings.

Abstract: Method and system for adaptive signal equalizing with alternating boost and amplitude controls. In accordance with one exemplary embodiment, data signal boost control is based on measured equalized and sliced data signal energies within a bandwidth disposed about a higher frequency, while sliced data signal amplitude control is based on measured equalized and sliced data signal energies within a bandwidth disposed about a lower frequency.

Abstract: Methods and apparatus are provided for adaptive link partner transmitter equalization. According to one aspect of the invention, a local transceiver adapts one or more equalization parameters of a link partner by receiving a training frame over a channel between the link partner and the local transceiver, wherein the training frame is comprised of a predefined training pattern; adjusting one or more of the equalization parameters of the link partner; and determining whether the equalization of the channel satisfies one or more predefined criteria based on whether the predefined training pattern is properly received by the local transceiver. The predefined training pattern can be a pseudo random pattern, such as a PN11 pattern Noise margins and jitters margins for the channel can optionally be improved.

Abstract: An equalizer circuit receives digital amplitude data A[N] which represents the amplitude level of the N-th (N is a nonnegative integer) signal to be transmitted via a transmission line and timing data T[N] which represents the cycle of the signal, and performs waveform shaping. The equalizer circuit includes: M (M is an integer) calculation units ECU1 through ECUm; and an adder ADD1 which adds the output data of the M calculation units ECU1 through ECUM and the amplitude data A[N] together so as to generate equalized amplitude data D[N]. A step response waveform RSTEP(t) for the transmission line is approximated by Expression RSTEP(t)=SSTEP(t)·(1?Sj=1:M fj(t)) using M (M is an integer of 2 or more) functions fj(t) (1?j?M) and a step waveform SSTEP(t) with the time t as an argument. The representative value of the function fj(t) in a range between T1 and T2 is represented by a function gj(T1, T2).

Abstract: An inter-carrier interference ICI cancellation method of a kth sub-carrier of an orthogonal frequency division multiplexing OFDM receiving signal (k is a natural number greater than 1 and less than or equal to n, n is a number of sub-carriers) includes canceling an inter-carrier interference element produced by at least one sub-carrier among inter-carrier interference elements of the kth sub-carrier by a decision feedback equalization DFE method, and canceling another inter-carrier interference element produced by at least another sub-carrier among inter-carrier interference elements of the kth sub-carrier by a linear minimum mean square error equalization LMMSE method.

Abstract: Systems and methods are provided for decoding signal vectors in multiple-input multiple-output (MIMO) systems, where the receiver has received one or more signal vectors from the same transmitted vector. The receiver combines the received vectors by vector concatenation The concatenated vector may then be decoded using, for example, maximum-likelihood decoding. In some embodiments, the combined signal vector is equalized before decoding.

Abstract: A method and a device for determining channel feedback information in a Long Term Evolution (LTE) system are provided. The method includes: obtaining an (N?1)th layer interference-plus-noise matrix in an LTE system, and obtaining an Nth layer interference-plus-noise matrix according to the (N?1)th layer interference-plus-noise matrix; and then, calculating a Signal to Interference plus Noise Ratio (SINR) corresponding to the Nth layer interference-plus-noise matrix according to the Nth layer interference-plus-noise matrix, and determining channel feedback information according to the SINR. It can be seen that, in the embodiments of the present invention, in a processing manner, a current layer interference-plus-noise matrix is calculated according to an obtained previous layer interference-plus-noise matrix through calculation in a calculation process of the channel feedback information, thus effectively reducing the calculation amount in the calculation process of the channel feedback information.

Abstract: A method, receiver and program for equalising digital samples of a radio signal received over a wireless communications channel. The method comprises: receiving digital samples of the radio signal; calculating equaliser coefficients in the frequency domain; transforming the equaliser coefficients from the frequency domain to the time domain; and equalising the digital samples in the time domain using the transformed time domain equaliser coefficients.

Abstract: A multiple carrier communication system includes a primary impulse shortening filter that receives an output signal of an analog to digital converter and accepts coefficients. A secondary impulse shortening filter receives the output signal of the analog to digital converter, outputs an output signal, and passes coefficients to the primary impulse shortening filter. A reference signal generator outputs a reference signal. A comparator compares the output signal and the reference signal and outputs a resulting error signal. An adaptive processor computes coefficients for the secondary impulse shortening filter based on the error signal.

Abstract: A differential transmission circuit comprises a sending unit that generates a pair of differential signals from an input signal, and sends the differential signals; a receiver that receives the differential signals sent by the sending unit; and a transmission path that transmits the differential signals from the sending unit to the receiver, wherein the sending unit has a selector that selects one of the input signal and a signal obtained by inverting a polarity of the input signal, and generates the differential signals from the signal selected by the selector.

Abstract: An equalizer provided in a digital transmitter compensates for attenuation in a signal channel to a digital receiver. The equalizer generates signal levels as a logical function of bit history to emphasize transition signal levels relative to repeated signal levels. The preferred equalizer includes an FIR transition filter using a look-up table. Parallel circuits including FIR filters and digital-to-analog converters provide a high speed equalizer with lower speed circuitry. The equalizer is particularly suited to in-cabinet and local area network transmissions where feedback circuitry facilitates adaptive training of the equalizer.

Abstract: A method and apparatus are provided for testing susceptibility of a receiver to intermodulation distortion of a digital channel, the method including selecting a first digital channel from channels in a composite signal, determining a first power measurement from the first digital channel, determining a total power measurement from other channels in the composite signal, and determining susceptibility of the first digital channel to intermodulation distortion by comparing the first power measurement and the total power measurement with intermodulation distortion characteristics of the receiver.

Abstract: Devices and methods for the cancellation for and identification of crosstalk for different application cases, particularly for near-end crosstalk (NEXT), are known. Too little attention is paid to the situation of non-reciprocally coupled systems. Therefore, devices and methods for cancellation and identification of far-end crosstalk (FEXT), which enable a reliable identification of an unknown system, are lacking in practice.

Abstract: Embodiments of the invention are generally directed to a high-speed differential energy difference integrator (EDI) for adaptive equalizers. In an embodiment, the EDI includes two differential full-wave rectifiers providing differential outputs that are cross-coupled to the inputs of an integration capacitor. In one embodiment, the active areas of the transistors of the differential full-wave rectifiers are substantially the same.

Abstract: Embodiments include a decision feedback equalizer (DFE) that includes a first comparator configured to receive as inputs a soft value and a first threshold, a second comparator configured to receive as inputs the soft value and a second threshold, a selector configured to select an output of either the first comparator or the second comparator as a DFE output based on one or more previous bits output by the selector; an error calculator configured to determine an error for the first comparator and the second comparator, and a threshold adjuster configured to adjust the first threshold and the second threshold, the first threshold and the second threshold each being a non-linear combination of one or more previous outputs of the selector.

Abstract: An adaptive transversal filter having tap weights Wj which are products of corresponding tap coefficients Cj and tap gains Mj is provided. A filter control loop controls all of the tap coefficients Cj such that an error signal derived from the filter output is minimized. One or more tap control loops controls a tap gain Mk such that the corresponding tap coefficient Ck satisfies a predetermined control condition. For example, |Ck| can be maximized subject to a constraint |Ck| Cmax, where Cmax is a predetermined maximum coefficient value. In this manner, the effect of quantization noise on the coefficients Cj can be reduced. Multiple tap control loops can be employed, one for each tap. Alternatively, a single tap control loop can be used to control multiple taps by time interleaving.

Abstract: A delay device that provides a delay amount to at least one of the in-phase signal and the quadrature signal, and a delay control section that controls the delay amount provided by the delay device based on a quality of the signals when the in-phase signal and the quadrature signal, to the at least one of which the delay amount is provided, at the delay device are converted into digital signals by the analog-digital converter, and the digital signal processing is carried out at the processor are provided. Thereby, the signal quality of recovered data at a receiving end of a multi-level phase modulation communication system is improved.

Abstract: A demodulator is provided that functions as a reduced-state equalizer and produces reliable soft bit values. According to an embodiment, soft bit values are generated for a sequence of transmitted symbols using a demodulator by updating an M-state trellis managed by the demodulator responsive to a transition from symbol time n?1 to symbol time n, where M is a function of the number of bits per symbol in the sequence of transmitted symbols. Survivor metrics associated with the M states of the trellis are saved each symbol time so that the demodulator can calculate soft bit values with regard to transitions from symbol time n+D?1 to symbol time n+D. The survivor metrics indicate the probability that each respective state represents the transmitted symbol associated with symbol time n+D?1. The trellis is traced back through to calculate soft bit values for a symbol detected at symbol time n?D based on survivor metrics saved for the M states at symbol time n?D.

Abstract: An inter-carrier interference (ICI) mitigating equalizer includes a channel estimator, a channel calculator, an ICI estimator, a subtracter, and an equalizer. The channel estimator estimates a channel response from a received signal, and the channel calculator calculates a basic component of a channel response and fluctuating components of the channel response from the estimated channel response. The ICI estimator multiplies the fluctuating components of the channel response by a received signal in a frequency domain, filters the multiplication results according to filter coefficients, and estimates an ICI component included in the received signal based on the filtering results. The subtracter subtracts the ICI component from the received signal in the frequency domain. The equalizer equalizes an output signal of the subtracter based on the basic component of the channel response.

Abstract: The present invention relates to the field of communication devices, e.g. wireless communication devices. More particularly, the present invention relates to the field of signal equalization, especially minimum mean square error equalization. The present invention especially relates to an equalizer for a communication device, a method of equalizing one or more received signals and a software program product for carrying out the method. The present invention reduces the size of a look-up table needed for a division operation and, generally, provides for a reduced complexity of the equalizer and receiver.

Abstract: An example Cognitive Radio (CR) described herein may include equalization and Automatic Modulation Classification (AMC). The equalization may employ digital filter techniques with an adjustable length or order. The output of the equalization may be provided to the AMC, where the AMC may be adapted to identify various characteristics about the RF environment and also to identify probabilities of classification associated with the performance of the AMC itself. The CR device may be configured to adjust the equalization using feedback from the AMC to enhance performance of each other.

Abstract: A digital communication system, an indoor unit, and an outdoor unit in which characteristic variation due to temperature is small are provided. The digital communication system comprises an IDU 1 and an ODU 6 connected through a cable 8, in which the IDU 1 includes a slope equalizer 2 which applies a given frequency characteristic to a baseband signal, a DAC 3 which converts the baseband signal from digital form into analog form, and an AGC circuit 5 which amplifies the baseband signal converted from digital form into analog form with a given amplification factor and outputs the signal to the ODU 6, and the ODU 6 includes a power detection circuit 7 which detects a length of the cable 8, determines a frequency characteristic to be applied to the baseband signal and an amplification factor according to the detected length of the cable 8 and notifies the determined frequency characteristic and amplification factor to the slope equalizer 2 and the AGC circuit 5 respectively.

Abstract: Typical transceivers have multiple near-end and multiple far-end crosstalk cancellation filters. Crosstalk cancellation is one of the largest contributors to power dissipation in the DSP portion of high speed Ethernet transceivers. By detecting the cable type, a transceiver could automatically turn off its crosstalk cancellation filters when driving shielded twisted pair (STP) cables and substantially reduce the overall power dissipation in this configuration. Adaptive digital crosstalk cancellers automatically adjust the coefficients of a digital filter to match the coupling function between two channels. The impulse response of an optimal crosstalk cancellation filter can be used to determine a metric indicating the amount of coupling between the two channels. STP cables will have a much lower amount of coupling between wire-pairs than unshielded twisted pair cables.

Abstract: A programmable logic device can be configured as a fractional rate resampling filter capable of performing downsampling prior to upsampling without modifying the overall filter response. Input data may be received at a first sample rate and may be downsampled to generate downsampled data. Portions of the downsampled data may be respectively output to different filtering paths. Each filtering path may include a cluster of filter components that corresponds to different subfilters of the overall filter response and may be operable to receive and process the different portions of the downsampled data. Outputs of each cluster may be combined to generate output data at a second sample rate. The resampling filter structure can reduce the number of multiplier circuits used by allowing time-division multiplexing among different filter components.

Abstract: Methods and apparatus to facilitate improve code division multiple access (CDMA) receivers are disclosed. An example method disclosed herein comprises: receiving a signal containing first portions that are based on known data and second portions that are based on unknown data; generating a training signal, from the received signal, that substantially represents one or more of the first portions; adapting filter coefficients using the training signal; and equalizing the received signal using the adapted filter coefficients.

Abstract: 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.

Abstract: The equalizer presented includes a first feed-forward equalization module, a second feed-forward equalization module, and a phase error corrector. The first and the second feed-forward equalization modules respectively receives an input real-part component signal and an input imaginary-part component signal of a complex input signal and respectively equalizes the input real-part component signal and the input imaginary-part component signal to generate a first real-part component signal and a first imaginary-part component signal. The phase error corrector is coupled to the first and the second feed-forward equalization modules for adjusting a complex phase corresponding to the first real-part component signal and the first imaginary-part component signal to generate a second real-part component signal and a second imaginary-part component signal according to a phase error information.

Abstract: A receiver for receiving a sequence of OFDM symbols transmitted via a channel. Each OFDM symbol comprises a plurality of data bearing sub-carriers and a plurality of pilot bearing sub-carriers. The receiver includes a channel estimator, and the channel estimator includes a pilot data extractor, a pilot data extrapolator and a pilot data interpolator operable to process the pilot data by interpolating between the extrapolated pilot data in time and frequency. The receiver also comprises a discontinuity detector for detecting a discontinuity in the pilot data processed by the channel estimator, and a controller, which upon detection of a pilot data discontinuity by the discontinuity detector, is operable to provide a control signal to the channel estimator which causes at least one of the pilot data extractor, the pilot data extrapolator and the pilot data interpolator to compensate for the discontinuity in the pilot data.

Abstract: A receiver receives data from a sequence of OFDM symbols transmitted via a channel, each OFDM symbol comprising a plurality of data bearing sub-carriers and a plurality of pilot bearing sub-carriers. The receiver includes a channel estimator for estimating the channel and an equaliser for reducing the effects of the channel so that the data can be recovered from the received OFDM symbols. The channel estimator includes a notch processor which is arranged in operation to detect a notch in a received OFDM symbol, the notch providing a plurality of the sub-carriers of the received OFDM symbol within a frequency range which were not transmitted by the transmitter, to determine one or more missing pilot sub-carriers which would have been transmitted within the notch sub-carriers of OFDM symbols according to a pilot sub-carrier pattern, and to generate one or more replacement pilot data symbol for a missing pilot data sub-carrier.

Abstract: Upstream frequency response measurement and characterization. Signaling is provided between respective communication devices within a communication system. Based upon at least one of these signals, one of the communication devices captures a number of sample sets corresponding thereto at different respective frequencies (e.g., a different respective center frequencies, frequency bands, etc.). Then, spectral analysis is performed with respect to each of the sample sets to generate a respective and corresponding channel response estimate there from. After this number of channel response estimates is determined, they are combined or splice together to generate a full channel response estimate. In implementations including an equalizer, different respective sample sets may correspond to those that have undergone equalization processing and those that have not.

Abstract: An apparatus comprises a summer suitable for subtracting a filtered feedback signal from an input; a symbol decision device suitable for receiving an output from the summer; a feedback filter suitable for filtering an output from the symbol decision device and for sending the filtered feedback signal to the summer, the feedback filter comprising an adjustable swing amplifier and an adjustable pole filter; and an adaptation algorithm suitable for simultaneously adapting both a pole setting and a swing setting based upon a least mean squared error criteria. The summer, the symbol decision device, and the feedback filter form a feedback circuit utilized to reconstruct an electrical signal distorted during transmission.

Abstract: An adjustable equalizer that includes a first branch including a low pass filter (LPF) and having a variable gain (?), and a second branch including a high pass filter (HPF) and having another variable gain (?). The equalizer can be implemented using CMOS technology so that the gain parameters ? and ? are independently adjustable and the equalizer is capable of equalizing an input indicative of data having a maximum data rate of at least 1 Gb/s. In some embodiments, the equalizer includes two differential pairs of MOS transistors and a controllable current source determines the tail current for each differential pair. When the equalizer includes purely resistive impedances Z0 and Z1, the equalizer's transfer function is Z1/Z0·(?+?·(1+s·C0·Z0)), where ? is a gain parameter determined by the tail current of one differential pair and ? is a gain parameter determined by the tail current of the other differential pair.

Abstract: A method for compensating frequency response of a filter unit in remote radio unit in real time, said remote radio unit comprises filter unit equalizer, transmitter observation receiver and antenna calibration receiver, said method comprising the steps of: receiving input signal of said filter unit by transmitter observation receiver; receiving output signal of said filter unit by antenna calibration receiver; calculating coefficients of filter unit equalizer in real time based on said input signal and said output signal; updating said filter unit equalizer based on said calculated coefficients in order to compensate frequency response of said filter unit. A device to carry out the above method, remote radio unit comprising said device and a telecommunication system comprising said remote radio unit are also provided.

Abstract: In a communication system, a postcoder is coupled between first and second portions of each of a plurality of receivers. The postcoder is configured to receive an adaptive index representation of a scaled signal associated with the first portion of a first one of the receivers, and to process the adaptive index representation using an adjusted postcoder coefficient to generate a postcompensation signal. The postcompensation signal is supplied by the postcoder to the second portion of a second one of the receivers for use in postcompensation of at least one signal received by the second receiver.

Abstract: System and method for adaptive signal equalizing in which overlapping data signal equalization paths provide cumulative data signal equalization to provide multiple equalized data signals having different available amounts of equalization. Signal slicing circuitry slices the equalized data signals to provide multiple sliced data signals, from which the sliced data signal selected as an output data signal is dependent upon the data rate of the incoming data signal.

Abstract: In a transmission diversity control method in which a request to start or stop transmission diversity is issued by a reception station to a transmission station having a transmission diversity function, the reception station is provided with an equalizer to reduce multipath interference on the basis of a signal correlation, a transmission diversity start request is issued from the reception station to the transmission station when an effect generated by the equalizer is small, and a transmission diversity stop request is issued from the reception station to the transmission station when the effect generated by the equalizer is large.

Abstract: The present invention provides a signal processing device and a signal processing method utilized in a communication system, wherein the communication system includes at least a channel. The signal processing device includes an analog-to-digital converter (ADC), a first adding unit, a feed forward equalizing unit, a data slicing unit, a second adding unit, an infinite impulse response (IIR) compensating unit, and an interference eliminating unit. The signal processing device and the signal processing method thereof disclosed in the present invention can utilize the IIR compensating unit to solve an error distortion problem in the communication system so as to improve the whole efficiency.

Abstract: In a communication system, a precoder is coupled between first and second portions of each of a plurality of transmitters. The precoder is configured to receive an adaptive index representation of a scaled signal associated with the first portion of a first one of the transmitters, and to process the adaptive index representation using an adjusted precoder coefficient to generate a precompensation signal. The precompensation signal is supplied from the precoder to the second portion of a second one of the transmitters for use in precompensation of at least one signal to be transmitted by the second transmitter.

Abstract: An adaptive equalizer circuit includes an equalizer circuit configured to produce an output data signal in response to an equalizing factor, a data detecting circuit configured to detect a signal level of the output data signal in a given unit time at predetermined timing, a boundary detecting circuit configured to detect a signal level of the output data signal at a timing that is ½ unit time away from the predetermined timing, and a control unit configured to detect, multiple times, a pattern having consecutive data items of a first value followed by a data item of a second value, and to adjust the equalizing factor such that a data detection value and a boundary detection value obtained for the data item of the second value are equal to each other a certain percentage of times, and are different from each other substantially the same percentage of times.

Abstract: A baseband-derived RF predistortion system using a lookup table having coefficients extracted at baseband and then applied at RF by means of a vector modulator. The architecture combines the narrowband advantage of envelope predistortion with the accuracy of baseband predistortion, and including compensation for memory effects. A polynomial-based alternative is also described.

Abstract: In the example embodiments, test signals sent from a transmitting system are received at a receiving system. The receiving system generates a determination signal indicating, in one embodiment, whether received signals have a desired relationship with respect to a clock signal at the receiving system. Timing of the clock signal or timing for transmitting signals may be adjusted based on the determination. In another embodiment, the receiving system generates a determination signal indicating whether the pulse width of a lone pulse signal equals a desired time interval. Equalization or pre-emphasis is controlled based on the determination signal.

Abstract: A high-speed bit stream interface module interfaces a high-speed communication media to a communication Application Specific Integrated Circuit (ASIC) via a Printed Circuit Board (PCB). The high-speed bit stream interface module includes a line side interface, a board side interface, and a signal conditioning circuit. The line side interface includes a media coupler that receives the line side media, such as copper media or optical media. The board side interface couples the high-speed serial bit stream interface module to the PCB. A signal conditioning circuit communicatively couples to the line side interface and to the board side interface. The signal conditioning circuit receives an RX signal from the line side interface, conditions the RX signal, and provides the RX signal to the board side interface. The signal conditioning circuit receives a TX signal from the board side interface, conditions the TX signal, and provides the TX signal to the board side interface.

Abstract: A code phase error estimating method includes calculating correlation for I and Q components of a reception signal, judging code phase based on the result of the correlation calculation; calculating a ratio of first difference to a second difference, where the first difference is a first correlation value minus a third correlation value and the second difference is a second correlation value minus the third correlation value, the first correlation value being a correlation value at the code phase, the second correlation value being a correlation value at a phase shifted from the code phase by X chip (0<X<1), and the third correlation value being a correlation value at a phase shifted from the code phase by Y chip (1<Y); and estimating the code phase error when the reception signal is a multipath signal.

Abstract: An adaptive equalizer including an equalizer filter and a tap coefficients generator used to process a sample data stream derived from a plurality of received signals is disclosed. The tap coefficients generator includes an equalizer tap update unit, a vector norm square estimator, an active taps mask generator, a switch and a pilot amplitude reference unit used to minimize the dynamic range of the equalizer filter. A dynamic mask vector is used to mask active taps generated by the equalizer tap update unit when an unmasked signal output by the equalizer filter is selected by the switch to generate an error signal fed to the equalizer tap update unit. A fixed mask vector is used to mask active taps generated by the equalizer tap update unit when a masked signal output by the equalizer filter is used to generate the error signal.

Abstract: A radio receiver for receiving a selected digital HDTV signal, irrespective of whether it is a complex-amplitude-modulation (QAM) or a vestigial sideband (VSB) signal, using the same tuner. The tuner supplies a final IF signal in a 6 MHz frequency band, the lowest frequency of which is not appreciably more than 2.38 MHz. The final IF signal is digitized for synchrodyning to baseband, with the 2.375 MHz difference between the carrier frequencies of QAM and VSB signals being taken into account in the digital synchrodyning circuitry. The carrier frequencies of the QAM and VSB final IF signals are regulated to be submultiples of symbol frequency by applying automatic frequency and phase control signals developed in the digital circuitry to a local oscillator of the tuner. The presence of the pilot carrier accompanying a selected VSB HDTV signal is detected for automatically switching the radio receiver for operation in a VSB signal reception mode.

Abstract: A circuit for the analog correlation of a 2.5 GHz signal to remove impairments such as echo, cross talk and intersymbol interference is described. Loop stability in a loop which generates an error signal and tap weights is achieved by providing a further delay from the taps of the delay line.