Abstract: A system for detecting and correcting for spurious frequencies that may coincide in a bandwidth of interest in an RF metrology system. The system can (1) utilize a deterministic scheme to detect an interference by a spurious frequency and correct the distortion effect or (2) utilize a mixed signal processing architecture to avoid the occurrence of spurious frequency contamination. A detection scheme identifies the event of distortion and triggers either (a) a shift in the analog to digital convert sample rate or (b) a mathematical vector manipulation. The shift of the analog to digital convert sample rate moves an aliased image of the spurious frequency outside of the frequency of interest. The mathematical vector correction removes the distortion and restores the signal of interest.

Abstract: The present invention provides a method of windowing signals in a communication system. The method includes accessing at least one first signal associated with at least one of a plurality of orthogonal frequencies and applying a window function to the at least one first signal to form at least one second signal. The at least one second signal remains substantially orthogonal to signals associated with the plurality of orthogonal frequencies.

Abstract: A system and method for modulating and amplifying an input signal are provided in a communication transmitter. The transmitter includes a pre-distortion lookup table containing pre-distortion lookup data. An auto-calibration module is in communication with the pre-distortion lookup table. The auto-calibration module is configured to operate during a closed-loop auto-calibration interval and to calibrate the pre-distortion lookup data to compensate for a non-linearity in the transmitter. The pre-distortion is based on the pre-distortion lookup data and is used during an open-loop operational interval.

Abstract: Systems and methods for utilizing new communication standards in wireless local area networks are provided that also support legacy wireless stations. The method can include user equipment determining channel state information, selecting a unitary channel decomposition precoder format based on the determined channel state information and transmitting the precoder format information to a base station. During a return transmission the user equipment can receive user data with the precoder format information and utilize a non-linear detector to demodulate and decode the user data. Based on the reception the user equipment can estimate channel quality; and transmitting channel quality information as feedback.

Abstract: A technique for PAR reduction involves producing an optimized clipping pulse. The optimized clipping pulse may be designed to meet certain requirements, such as a spectral mask target or an EVM target, when applied to a signal.

Abstract: A terminal apparatus including a block generation unit, a transmission timing calculation unit, and a transmission unit. The block generation unit generates a block that includes a plurality of symbols being temporally consecutive and one or more repetition symbols added to a head end of the symbols. The transmission timing calculation unit calculates a transmission timing at which the block is to be transmitted to an external apparatus according to a symbol rate of the block and a number of extended repetition symbols included in the block. The transmission unit transmits the block to the external apparatus at the transmission timing calculated by the transmission timing calculation unit.

Abstract: System and method of locating an interferer and mitigating its effect for stations of a wireless local area network. Embodiments provide a protocol and mechanism to evaluate the interferer location relative to a wireless link and to take accurate actions to mitigate the interference effect for specific cases. A method includes classifying a location of an interferer relative to a wireless communication device based on a comparison with a clear-channel threshold and a noise-tolerability threshold of the device, categorizing a location of the interferer relative to a wireless link based on a combination of the interference categories for the transmitting and the receiving devices, and mitigating interference in the wireless network according to the categorization. For example, in some cases, mitigating includes adapting a noise-tolerability threshold of the transmitting device to allow transmission.

Abstract: A method for transmitting multicast data in a WiMax/WiBro relay system, including transmitting carrier-interference-noise ratios from UEs to corresponding Relays; selecting the minimum value among the carrier-interference-noise ratios; determining the modulation and coding mode according to the selected minimum value; transmitting the modulation and coding mode to BS; selecting a modulation and coding mode with a highest rate for multicast data on an access link; transmitting the final modulation and coding mode to the Relays; and transmitting data via the access link with the modulation and coding mode determined by the BS.

Abstract: Device, system, and method of flicker noise mitigation. For example, an apparatus includes a digital adaptive filter to mitigate flicker noise from a received Orthogonal Frequency-Division Multiplexing (OFDM) signal, wherein the digital adaptive filter includes: a prediction filter to estimate a value of the flicker noise based on linear combination of past low-pass filtered signal samples; a trainer sub-circuit to modify a coefficient of the prediction filter based on a difference between: a known incoming signal filtered by the prediction filter in a training stage, and a locally-generated reference copy of the known signal; a first path including a first pair of analysis-synthesis filters; and a second, parallel, path including a second pair of analysis-synthesis filters and further including the prediction filter.

Abstract: Multi-carrier transmission is performed without inserting a repetitive signal into guard interval periods. A transmitter provides guard interval periods by using a null signal to save transmission power and prevent the deterioration of the SN ratio. Delayed waves at the head of each received symbol cause high-frequency waves to occur and carriers to interfere with one another. Accordingly, a receiver adds a component following each received symbol to a delayed-wave component at the head of the received symbol. As a result, the delayed-wave component at the head of the received symbol and the added component become continuous in wave form and subcarriers do not interfere with each other.

Abstract: A transmitter includes a polar modulator that creates phase and amplitude signals which in turn drive a power amplifier. To compensate for AM to PM conversion of the amplitude signal into the amplified signal, a compensation signal is generated from the amplitude signal and combined with the phase signal such that when amplified, the compensation signal cancels the AM to PM conversion. The compensation signal may have an offset term, a linear term, a quadratic term, and a cubic term. A second embodiment comprises a technique by which AM to AM conversion may concurrently be addressed using a second compensation signal.

Abstract: Systems and methods are provided for providing a hybrid signal having a reduced crest factor. A digital signal is generated that assumes one of a plurality of vector states at discrete sampling times, with each of the plurality of vector states having an associated phase. An analog signal is monitored to determine when a phase of the analog signal is aligned with the phase of a vector state assumed by the digital signal. A crest factor reduction is applied to the digital signal if the digital signal assumes a vector state having an associated phase aligned with the phase of the analog signal to provide a compressed digital signal. The compressed digital signal and the analog signal are combined to provide the hybrid signal. The analog signal is not altered prior to being combined with the compressed digital signal.

Abstract: Systems and methods for monitoring impulse noise are described. At least one embodiment is a method, which comprises detecting whether impulse noise is present and in response to detecting the presence of impulse noise, performing time domain analysis to determine whether one or more impulse noise sources are present based on minimum interarrival time and maximum impulse length. The method further includes performing frequency domain analysis to estimate frequencies associated with the one or more impulse noise sources and based on the time domain analysis and frequency domain analysis, providing a total number of impulse noise sources and frequencies associated with the impulse noise sources. In this regard, the embodiments described herein provide dual-speed monitoring of impulse noise in the form of short-term and long-term monitoring.

Abstract: The present invention relates, in general, to a joint channel and frequency offset estimation apparatus and method based on a multi-band-orthogonal frequency division multiplexing system, and, more particularly, to a joint channel and frequency offset estimation apparatus and method based on an MB-OFDM system, which uses low-rank LMMSE channel estimation, in which a low-rank is applied to the MB-OFDM system, thus decreasing complexity, and adds a simple structure using the autocorrelation characteristics of an estimated channel, thus joining channel estimation to frequency offset estimation at low complexity. The apparatus includes a channel estimator for receiving a Fourier-transformed OFDM signal, and calculating results of channel estimation using a Linear Minimum Mean Square Error (LMMSE) channel estimation, which minimizes a Mean Square Error (MSE) between an actual channel value and an estimated channel value.

Abstract: A communications receiver may include an adaptive filter unit for removing coherent interference components from a received signal. In the absence of a signal of interest, the filter may adapt dynamically to remove current interference components. When a signal of interest is detected, the filter may be controlled to stop (or at least reduce) its adaptation, to prevent removal of the signal of interest. The received signal may be down-converted to a complex baseband by conditioning circuitry. A detector may detect the signal of interest, and control the filter. Autocorrelation may be used to estimate a characteristic of the signal of interest in the complex baseband. The detector may include hysteresis to react quickly to the start of signal of interest, and more slowly to an end of the signal of interest. The signal of interest may be a frequency shift keyed (FSK) signal. A demodulator may demodulate FSK components based on the autocorrelation result.

Abstract: Methods and apparatus for allocating tones for communications in the strip-symbol periods in an OFDM system are described. In a strip-symbol, the signal is transmitted using the tones in a tone subset, which is selected from a predetermined set of tone subsets according to a fixed schedule sequence. Adjacent base stations and sectors use the same set of tone subsets but different schedule sequence to minimize the number of collisions between the tone subsets used in adjacent sectors and neighboring cells.

Abstract: Method and apparatus are disclosed for obtaining improved performance when using Forward Error Correction (FEC) with channels experiencing block fading or burst jamming over some number of contiguous symbols. One suitable application is when the channel is periodically obstructed due to the rotation of a propeller blade, resulting in a periodic block fading channel. During operation zero symbols are inserted into the received signal stream, prior to the FEC decoder at times that are estimated or otherwise determined to correspond to periods of jamming or severe fading. The zero symbols effectively “erase” the severely degraded symbols. The zero symbols are less detrimental to the FEC decoder than the severely degraded symbols, especially when the channel interleaving/de-interleaving operations result in the zero symbols being temporarily distributed over a large block of received symbols.

Abstract: A signal receiving apparatus includes an indicating unit, a receiving, a system unit which comprises a plurality of electronic components to provide signal processing, a storing unit to store information related to a noise level, and a controlling unit to estimate a signal power level of the data received by the receiving unit, to compare the estimated signal power level of the data with the noise level generated by a power supply to the system unit, and to control the indicating unit to indicate whether the data can be received.

Abstract: A quadrature modulator divides a part of a transmitted signal to generate a cancel signal. A signal comparator compares the amplitude and phase of the cancel signal which is generated by the quadrature modulator with those of a received signal, and outputs signals corresponding to the comparison results to the quadrature modulator. The quadrature modulator generates the cancel signal on the basis of the output signals of the signal comparator, and these components perform feedback control such that the cancel signal has the same amplitude as the leakage signal and is in phase with the leakage signal. A combiner combines the cancel signal with an antiphase cancel signal, which is made to be in opposite phase with the cancel signal outputted from the quadrature modulator, to cancel out the leakage signal.

Abstract: A system having a signal processor for detection of a signal type of a signal is disclosed. One embodiment includes a processor designed to determine a first variable which is characteristic of a first spectrum element of the signal spectrum, and to determine a second variable which is characteristic of a second spectrum element of the signal spectrum. A system is provided for determination of a ratio between the first variable and the second variable, and a detector which is designed to detect the signal type on the basis of the ratio.

Abstract: An apparatus and method for improving a symbol error rate of an M-ary phase shift keying (M-PSK) system having a quadrature error are provided. The apparatus includes: a conversion parameter detector that detects a conversion parameter and converts a symbol decision region using the quadrature error and at least one pair of first received symbols; and a converter & determiner converting a pair of second received symbols using the detected conversion parameter, and determining a transmission symbol according to a symbol of the converted pair of second received symbols. An increase in a symbol error rate due to the quadrature error can be prevented and the quadrature error can be easily estimated.

Abstract: An apparatus, system, and method are disclosed for dynamic phase equalization in a communication channel. A transmitter history module stores a plurality of bits from a data stream that is transmitted through the communication channel. A transmitter detection module detects a pre-transition bit of a first value that is preceded in the data stream by at least one bit of the first value and followed by a transition bit with a second value. A driver module transmits the data stream by driving the communication channel. A transition module pre-drives the communication channel to the second voltage of the transition bit during a bit time interval of the pre-transition bit.

Abstract: A transmitter includes a polar modulator that creates phase and amplitude signals which in turn drive a power amplifier. To compensate for AM to PM conversion of the amplitude signal into the amplified signal, a compensation signal is generated from the amplitude signal and combined with the phase signal such that when amplified, the compensation signal cancels the AM to PM conversion. The compensation signal may have an offset term, a linear term, a quadratic term, and a cubic term. A second embodiment comprises a technique by which AM to AM conversion may concurrently be addressed using a second compensation signal.

Abstract: A differential receiver which provides for estimation and tracking of frequency offset, together with compensation for the frequency offset. Estimation and tracking of the frequency offset is undertaken in the phase domain, which reduces computational complexity and allows frequency offset estimation and tracking to be accomplished by sharing already-existing components in the receiver. Compensation for the frequency offset can be performed either in the time domain, before differential detection, or in the phase domain, after demodulation, or can be made programmably selectable, for flexibility.

Abstract: A transmitter includes a polar converter to generate an amplitude signal and a phase signal, which in turn is converted to a frequency signal. The amplitude signal is directed to a compensator and a compensation signal is generated. The compensation signal is combined with the amplitude signal and the combined signal is presented to the power amplifier. The AM to AM conversion is reduced such that the output signal of the power amplifier contains substantially no spurious components.

Abstract: A method for communication using a modulation scheme defined in a signal space includes determining demodulation confidence levels at a plurality of points distributed over the signal space. Weights are assigned to the respective points responsively to the demodulation confidence levels. A signal is received and demodulated using an adaptive loop so as to derive a corresponding signal point in the signal space. The adaptive loop is adjusted responsively to a weight assigned to the derived signal point.

Abstract: A wireless device receives an input signal representing a signal of interest (e.g., one or more portions of a packet) on a wireless medium. The input signal may, in addition, contain narrowband interference signals. The wireless device removes the signal of interest from the input signal to produce a residue signal, and analyzes the residue signal to determine the presence of any interference bands in which narrowband interference signals may be present. The wireless device then removes the detected interference bands from the input signal. The residue signal may reveal the presence of interference signals, which might otherwise be hard to distinguish in the input signal. Thus, interference signals with power levels much lower than the power of the signal of interest may be detected and removed.

Abstract: A predistortion linearized amplifier system that uses analog polynomial based predistortion is disclosed. An analog polynomial function generator receives polynomial parameter updates from a polynomial parameter generator. The polynomial parameter generator uses a combination of analog and digital signal processing to create the parameter updates. This processing is performed on input signal amplitude, detected using analog circuits, and RF coupled samples of the input signal, and the output signal. By using a combination of analog and digital signal processing means, digital processing can be performed at sub-Nyquist rates, significantly reducing the cost of digital circuits. Also, since the predistortion modulation signal is created with an analog function generator, time correlating delay is minimized reducing circuit costs.

Abstract: An apparatus and method for estimating the CINR of an uplink channel in a broadband wireless communication system are provided, in which tiles being subcarrier sets are separated from a feedback signal received on the uplink channel. All symbols included in the tiles of the feedback signal are correlated with each of codewords, the absolute values of the correlations are squared for the each codeword and summed, a codeword with a maximum sum from among the codewords is selected. Received power level and noise power level are calculated using all the symbols included in the tiles of the feedback signal correlated with the codeword with the maximum sum, and the CINR of the uplink channel is estimated using the received power and the noise power levels.

Abstract: A technique for interference suppression in MC-CDMA systems is proposed which exploits the structural differences in signals that arrive at the receiver with Doppler shifts or carrier offsets. Oversampling the received signal in the frequency domain and properly combining the samples provides the interference suppression. Frequency domain oversampling is accomplished by using a time extension of the conventional MC-CDMA signal. Furthermore, a receiver structure is introduced that despreads and combines groups of samples so that a linear minimum mean-squared error solution for combining the groups is easily found. This combining scheme increases the signal-to-interference ratio (SIR) experienced by the desired user in the MC-CDMA system. In addition, the receiver performs well in severe near-far scenarios when there is sufficient Doppler separation between the signals of the desired user and an interferer.

Abstract: Embodiments of a wireless communication device and a method for reducing in-band interference in a GPS receiver are generally described herein. Other embodiments may be described and claimed. In some embodiments, an adaptive filter may be used to measure in-band interference from in-band signals generated from coupled signals of a handset transmitter. The in-band interference may be subtracted from digital GPS signals provided by the GPS receiver. In some embodiments, the in-band interference is not subtracted from the GPS signals when the handset transmitter is not active.

Abstract: A noise filter, used for a digital signal, configuring an [N?1]-stage filter by connecting the N-number of flip flops in series comprises a selection unit for outputting a filter output signal by selecting one of signals filtered by one to (N?1) stages based on a selection signals; and a wave form check unit for making the selection unit change a selection thereby by changing a value of the selection signal based on a pulse width on the filter output signal which is output from the selection unit.

Abstract: In order to compensate for a frequency offset or a change in the phase of the transmission channel over time during mobile radio transmission of data symbols, the data symbols are transmitted by way of carrier-frequency, modulated data bursts. Sample values of the received signal, which are known in advance and correspond to first and second symbols, are evaluated in order to estimate the frequency offset or the change in the phase of the transmission channel over time. These first and second symbols are transmitted with a defined phase angle by way of the data burst, and are arranged separated from one another in the data burst. Edge symbols in a data burst are advantageously used as first and second symbols, or as a symbol pair, for estimation.

Abstract: Disclosed is a detection or communication system and method. The detection or communication method and system includes a code generator for generating a set of N complementary Golay sequences, the code generator encodes a baseband signal with the complementary Golay sequences wherein the complementary Golay sequences have an ideal autocorrelation and the sum of cross-correlations of every Golay complementary sequence set is zero thereby reducing phase difference and Doppler effects.

Abstract: An scheme to provide local oscillator feedthrough offset cancellation to remove baseband and radio frequency coupled offsets. Two separate offset cancellation currents are injected at a driver which drives a baseband signal into a mixer to mix with a local oscillator signal. One offset cancellation current cancels a baseband local oscillator feedthrough offset, while the other offset cancellation current cancels a radio frequency local oscillator feedthrough offset.

Abstract: The present invention relates to a method for the transmission of data in a multi-carrier system, provided with a frequency band, the carrier frequencies of which are distributed in a sub-carrier band, dividing the frequency band. On the transmission side, dependent on current transmission properties, an adaptive pre-emphasis of the transmission signal is carried out for a part of the carrier frequencies in the sub-carrier band. The transmitter thus has the capacity to determine current transmission properties as well as adaptive pre-emphasis of a part of the carrier frequencies in the sub-carrier band of the transmission signal.

Abstract: Different sets of symbols are precluded at prescribed times in time-dependent trellis coding. This increases the distances between different individual symbols as well as the distances between trellis codes, which increases the robustness of data transmission. The symbols that are precluded in this time-dependent trellis coding are determined in advance according to a prescribed pattern, which pattern does not depend on the history of previous symbols. The Viterbi decoder used for trellis decoding in a receiver can be designed to take advantage of knowledge concerning which different sets of symbols are precluded at prescribed times.

Abstract: Methods and systems for processing a single sub-channel that includes two or more combined channels. Using intermediate frequency sub-sampling, two or more channels from a broad band signal are combined into a single sub-channel for further analog and digital processing. Each of the two or more channels is down converted to an intermediate frequency, filtered to remove certain undesired channels, and combined such that the two or more channels are adjacent to each other. A digital representation of the sub-channel is produced from the combined intermediate frequency channels. Each channel within the digital representation is down converted to baseband, and the in-phase and quadrature components are separated from each other. Compared to one direct down conversion technique, intermediate frequency sub-sampling as described in the application may reduce the number of analog to digital converters and control amplifiers used in analog processing by a factor of four.

Abstract: A denoising process models a noisy signal using classes and subclasses of symbol contexts. The process generates class count vectors having components that combine occurrence counts for different symbols in different contexts. Biases determined separately for each subclass and a fixed predictor indicate which symbol occurrence counts for different context are combined in the same component of a class count vector. For impulse noise, the bias for a subclass can be the average error that results when the fixed predictor predicts non-noisy symbols found in contexts of the context subclass. Denoising of impulse noise can select replacement symbols without matrix multiplication or a channel matrix inverse by evaluating distributions that result from subtracting error probabilities from probability vectors associated with respective contexts. Probability mass can be moved from adjacent components of the probability vector to assure that subtraction of the error probabilities leaves non-negative results.

Abstract: A digital amplifier and method are provided to convert digital base-band signals to a pair of digital switching waveforms switching at a carrier frequency to create a modulated RF signal. The digital amplifier contains variable frequency suppressed carrier PWM generators that produce in-phase and quadrature-phase differential signals, a mixer that combines the differential signals, a decoder that decodes the combined signals, and a power stage that receives signals from the decoder and provides an amplified signal at the carrier frequency using switches. The mixer combines the differential signals such that only one of the differential signals is output in a period. The carrier generators have integral noise shaping and use a random period signal to re-distribute quantization noise to a band outside an RF band of interest and reduce EMI of the RF signal.

Abstract: Various embodiments are disclosed relating to a wireless transceiver. In an example embodiment, a wireless transceiver may include a transmitter adapted to output a signal at an image frequency (e.g., a simulated image) for a channel during a first mode (e.g., calibration mode) of operation. The wireless transceiver also includes a receiver adapted to receive, via loopback from the transmitter, the (e.g., simulated) image frequency signal and to determine digitally a receiver in-phase/quadrature-phase (I/Q) signal calibration adjustment based on the (simulated) image frequency signal to improve a match in amplitude and a predetermined phase shift between I and Q signals of the receiver during the first (e.g., calibration) mode of operation. The I/Q calibration adjustment may be applied to received signals during a second mode (e.g., operation mode) of operation to improve image rejection.

Abstract: In a communication system transmitter, a baseband processor is configured for coupling via an upconverter to an input of a power amplifier of the transmitter. The baseband processor comprises a crest factor reduction element implementing an adaptive peak windowing algorithm for application to an input signal, the adaptive peak windowing algorithm comprising a function that is adaptively adjustable for reducing interference among different peaks of the input signal.

Abstract: A communications receiver may include an adaptive filter unit for removing coherent interference components from a received signal. In the absence of a signal of interest, the filter may adapt dynamically to remove current interference components. When a signal of interest is detected, the filter may be controlled to stop (or at least reduce) its adaptation, to prevent removal of the signal of interest. The received signal may be down-converted to a complex baseband by conditioning circuitry. A detector may detect the signal of interest, and control the filter. Autocorrelation may be used to estimate a characteristic of the signal of interest in the complex baseband. The detector may include hysteresis to react quickly to the start of signal of interest, and more slowly to an end of the signal of interest. The signal of interest may be a frequency shift keyed (FSK) signal. A demodulator may demodulate FSK components based on the autocorrelation result.

Abstract: A channel optimization system for use with a communications channel and method of separating and encoding signals associated with the communications channel. In one embodiment, the channel optimization system includes an assorter that receives first and second signals having disparate transmission characteristics and selects one of the first and second signals. The channel optimization system also includes a translator, coupled to the assorter, that encodes the selected one of the first and second signals into a symbol representation as a function of a transmission characteristic associated therewith.

Abstract: The system and method enable simpler analog processing in a transmitter by reducing the number of bits in a digital signal through delta sigma modulation. Selection of current sources in a digital to analog converter of the transmitter is done using a randomization circuit.

Abstract: An impulse noise remover includes: a storage module for storing a plurality of digital values derived from a received signal; a calculating module coupled to the storage module for calculating a first detection value according to a first subset of the plurality of digital values, and for calculating a second detection value according to a second subset of the plurality of digital values; a control unit coupled to the calculating module for identifying a target digital value associated with impulse noise according to the first and the second detection values; and a correcting unit coupled to the storage module and the control unit for replacing the target digital value with a predetermined value.

Abstract: An embodiment of the present invention provides an apparatus, comprising a receiver capable of selecting optimal pilot locations and providing feedback of the pilot locations to a transmitter in communication with the receiver. The optimal pilot locations may be selected by locations that avoid strong interference or platform noise at the receiver, by locations that avoid deep fading, by locations that maximize the spacing between pilot tones at the two ends of a wireless frequency band or by locations that equalize the interspacing between any two adjacent pilots.

Abstract: The present invention relates to a high speed line equalizer and a method thereof. The high speed line equalizer receives and amplifies one clock signal and at least more than one data signal. The high speed line equalizer comprises an input buffer, a first filter, at least more than one second filter, and an adaptive loop. The input buffer amplifies the clock signal. The first filter controls a high frequency gain of the clock signal according to a gain control signal. The at least more one second filter controls a high frequency gain of the at least more than one data signal according to the gain control signal. The adaptive loop calculates a gain difference between high frequency components of the amplified clock signal from the input buffer and the clock signal of which high frequency gain is controlled and outputs the gain difference as the gain control signal.

Abstract: An apparatus for compensating nonlinearly distorted multicarrier signals, a multicarrier signal receiver using the same, and a method therefor are provided, where the apparatus for compensating multicarrier signals and the multicarrier signal receiver using the apparatus extract parameter information on the HPA mode from the received signal so that nonlinear distortion of the received multicarrier signal is compensated for even though an accurate transfer function of a high power amplifier (HPA) is not known and side information or a special training signal is not transmitted when a signal is transmitted, such that nonlinearly distorted multicarrier signals such as OFDM signals transmitted by an HPA having a variety of transfer functions can be adaptively compensated and therefore a demodulated signal with an improved symbol error rate (SER) can be obtained.

Abstract: A mixer for mixing a digital input signal with a sampled sinusoidal signal, comprising a calculating circuit for calculating multipliers (MC) of a multiplier group (MG) which exhibits a number of dividing circuits for dividing the digital input signal applied to an input of the mixer, and a number of switchable adders/subtractors, the dividing factors of the dividing circuits being Homer coefficients of the resolved multipliers (MC) of the multiplier group (MG), the adders/subtractors being controlled in dependence on a first control bit (SUB/ADD) read out of a memory; a demultiplexer for switching through a zero value or the multiplier (MC) calculated by the calculating circuit in dependence on a second control bit (zero) read out of the memory; and comprising a sign circuit for outputting the positive or negative value switched through by the demultiplexer to an output of the mixer in dependence on a third control bit (SIGN) read out of the memory.