Abstract: In a multivalue modulation type with one pilot symbol inserted for every 3 or more symbols, signal points of each one symbol immediately before and after a pilot symbol are modulated using a modulation type different from that for pilot symbols. In this way, it is possible to suppress deterioration of the accuracy in estimating the reference phase and amount of frequency offset by pilot symbols and improve the bit error rate characteristic in the signal to noise ratio in quasi-coherent detection with symbols whose symbol synchronization is not completely established.

Abstract: Systems and methods of classifying and decoding wireless signals are disclosed. A receiver may receive wireless signals from multiple transmitters. The receiver may use sphere decoding to classify the wireless signals (e.g., determine the modulation scheme of the wireless signals) and decode the wireless signals (e.g., determine the symbol and/or symbols transmitted using the wireless signals).

Abstract: The present invention describes a method and a system for executing preamble detection, symbol timing recovery, and frequency offset estimation that are applied to a PHS system for executing the preamble symbol detection and timing recovery. The system includes a first absolute value circuit, an average circuit, a multiplier, a sample and accumulate circuit coupled to the multiplier, a second absolute value circuit, a first compare circuit, and a second compare circuit, such that the system with the foregoing structure can detect a preamble symbol by less symbols while performing a timing recovery. The invention also describes a frequency offset computation method and its circuit.

Abstract: According to one embodiment, an ASK demodulator includes a rectifier, a first low-pass filter, a second low-pass filter, a comparator, and a threshold controller. The rectifier rectifies an ASK signal. The first low-pass filter outputs a signal corresponding to an envelope curve output from the rectifier. The second low-pass filter outputs an integrated signal of the signal output from the first low-pass filter. The comparator detects an output logic in accordance with comparison between the signal output from the first low-pass filter and a threshold obtained by adding a predetermined hysteresis width to the integrated signal output from the second low-pass filter. The threshold controller controls the threshold by setting the predetermined hysteresis width based on a direct current offset voltage caused by element dispersions of the comparator.

Abstract: A method for demodulating signals in a multi-input multi-output (MIMO) receiver includes obtaining a transformed vector by a coordinate transformation of a received observation vector using a unitary matrix determined through QR decomposition of an estimated channel matrix; maintaining a list containing nodes along with a cost metric for each node; using the list to generate soft-outputs in the form of log-likelihood ratios (LLRs) for selected symbols of interest, based on the transformed vector and a lower triangular matrix determined through QR decomposition of the estimated channel matrix and the constellations to which the input symbols belong.

Abstract: A receiver receives a received signal from a communication link, the received signal comprising a stream of symbols modulated onto a carrier, each of the stream symbols selected from a constellation of symbols to represent a plurality of encoded data bits. The receiver comprises a demodulator to produce a stream of received symbols derived from the received signal; a channel decoder to produce a received stream of data bits derived from the stream of received symbols; and a memory device to store information related to the plurality of symbols in the constellation.

Abstract: A method for symbol tracking in AM in-band on-channel radio receivers comprises the steps of: receiving a stream of time domain samples; assembling a set of the time domain samples equal to a symbol time plus a half symbol delay in response to a symbol timing adjustment value for each symbol period; interpolating the time domain samples; partitioning the interpolated time domain samples into a first group of samples representing half-off symbols and a second group of samples representing on-time symbols; processing the first and second groups of samples to produce the symbol timing adjustment value; and outputting the second group of samples representing on-time symbols at a symbol rate. An apparatus that performs the method is also included.

Abstract: The method is for estimating the fading coefficients of a plurality of transmission channels on which signals to be sent, generated as a function of a sequence of symbols, are transmitted according to a particular modulation, e.g. AM-PSK modulation. The fading coefficients are estimated by using estimations of the transmitted symbols obtained in advance, thus obtaining DC components of the received signal by coherent demodulation locked to the phases of the transmitted AM-PSK signals, and processing these DC components. The method may not require the choice of a stochastic distribution model of the channel fading, thus it remains efficient even when the channel characteristics vary significantly. Moreover, the method works correctly even if the received stream is disturbed by inter-symbolic interference (ISI) and/or by multi-path fading.

Abstract: Disclosed are a method for re-ordering multiple layers and detecting signals and a receiver using the same to be able to exert performance approaching a maximum likelihood scheme while having lower complexity than that of the maximum likelihood scheme in a multiple input multiple output (MIMO) antenna system in a form where each layer is modulated and transmitted with different modulation orders.

Abstract: A circuit is provided comprising detector circuitry, calculating circuitry, and determining circuitry. The detector circuitry is figured to generate an I data signal magnitude value of a sampled I data signal and a Q data signal magnitude value of a sampled Q data signal. The calculating circuitry is configured to calculate a phase shift angle ?I between first and second equal and constant or substantially equal and constant envelope constituents of the sampled I data signal and to calculate a phase shift angle ?Q between first and second substantially equal and substantially constant envelope constituents of the sampled Q data signal. The determining circuitry is configured to determine in-phase and quadrature amplitude information of the substantially equal and substantially constant envelope constituents of the sampled I signal and to determine in-phase and quadrature amplitude information of the first and second substantially equal and substantially constant envelope constituents of the sampled Q signal.

Abstract: Embodiments of a method and an apparatus for detecting multiple complex-valued symbols belonging to discrete constellations. The method and apparatus is a detector that finds a closest vector, or a close approximation of it, to a received vector. The invention also gets (optimally, in case of two transmit sources) or closely approximates (for more than two transmit sources) the most likely sequences required for an optimal bit or symbol a-posteriori probability computation. Also part of the present invention is represented by Also embodiments of a method and an apparatus to determine a near-optimal ordering algorithms for the aforementioned purpose. The method and apparatus achieves optimal performance for two transmit antennas and achieves near-optimal performance for a higher number of antennas, with a lower complexity as compared to a maximum-likelihood detection method and apparatus. The method and apparatus are suitable for highly parallel hardware architectures.

Abstract: A method for carrier tracking in AM in-band on-channel radio receivers comprises the steps of receiving an input signal, generating a local oscillator signal in response to an oscillator control signal, mixing the input signal with a local oscillator signal to produce a first signal, filtering the first signal to produce a filtered first signal at a decimated sample rate, detecting the phase error and frequency error of the filtered first signal normalized to mitigate effects of signal fades, and using an adaptive loop filter to produce the oscillator control signal in response to the phase error and frequency error of the filtered first signal. An apparatus that performs the method is also provided.

Abstract: A receiver supports a single carrier (SC) form of modulation and a multi-carrier form of modulation such as orthogonal frequency division multiplexing (OFDM). Upon receiving a signal, the receiver determines a maximum fluctuation range (MFR) as a function of at least a fourth-order cumulant of a received signal; and classifies a modulation type of the received signal as a function of the determined maximum fluctuation range. After determining the modulation type of the received signal, the receiver switches to that modulation mode to recover data from the received signal.

Abstract: A radio frequency (RF) receiver for receiving transmissions of different modulations includes cycling between a first mode for receiving transmissions of a first modulation that occurs frequently and a second mode for receiving transmission of a second modulation that occurs infrequently. The example RF receiver is cycled between a first modulation for receiving a frequency shift keyed (FSK) transmission from a tire pressure monitoring (TPM) system and a second modulation for receiving an amplitude shift keyed (ASK) transmission from a remote keyless entry (RKE) system. The RF receiver cycles between different modulations to detect the most frequent FSK modulated transmissions while also detecting and receiving the relatively infrequent ASK modulated RKE transmissions without an undesirable delay.

Abstract: A control signal is wirelessly transmitted from a first radio communication unit of a portable communication device to a second radio communication unit. The portable communication device is provided for radio communication over a first radio frequency band using a first modulation technique. The control signal is transmitted by generating a control signal, switching off the first modulation of a carrier signal, shifting the frequency of the carrier signal from a first radio frequency band to a second radio frequency band for the first radio communication unit, switching on the second modulation of the carrier signal having a frequency within the second radio frequency band, wherein the carrier signal is modulated with the control signal, and transmitting the control signal modulated carrier signal wirelessly over the second radio frequency band to the second radio communication unit.

Abstract: Provided is a modulation device which generates a phase modulation signal and an amplitude modulation signal and can correct an I/Q orthogonal shift and reduce degradation of the ON/OFF ratio. In the device, a phase shifter (174) controls voltage applied to a capacitor in accordance with a control signal outputted from a phase control unit (180) and adjusts the capacitance so as to shift the phase of a carrier generated by an oscillator (173). The phase control unit (180) estimates a phase shift of a phase shifter (174) in accordance with an output RF signal (S140) by using the phase shift estimation method. Furthermore, the phase control unit (180) performs tuning of the phase shifter (174) according to the estimated value of the phase shift of the phase shifter (174) so that a phase difference between carries of an I signal (S125) and a Q signal (S135) is 90 degrees.

Abstract: Disclosed is a broadcast receiver. The broadcast receiver comprises a signal receiver for tuning and outputting a Q channel of a digital broadcasting signal, a demodulator for demodulating a signal of the received channel and checking a lock state M or an unlock state of a gain control signal and a timing control signal of the channel, and a demodulation controller for controlling o an operation of the demodulator and detecting a lock state of the channel based on the lock state of the gain control signal and the timing control signal.

Abstract: A device that detects the presence of several amplitude-modulated high-frequency signals in a sum signal with closely-adjacent carrier frequencies. The sum signal is phase-demodulated by a phase demodulator and Fourier-transformed by a Fourier-transformation device. On the basis of the Fourier transform, the presence of several carrier frequencies is determined by an evaluation device.

Abstract: The present invention relates to a communication field and particularly to a method and apparatus for transmitting/receiving multimedia broadcast/multicast data based on hierarchical modulation in order to solve the problem of low efficiency of conventional methods.

Abstract: The invention relates to a method for determining the sampling instant of a clock signal (ti) for a circuit for determining symbols (Se) from a digitized signal (sd, S) which is coupled to at least one quadrature signal pair of a modulation method (QAM), wherein the digitized signal is converted to polar signal coordinates (R, ?) with a radial component (R).

Abstract: A MIMO detection method for a receiver in a MIMO system using N-QAM for modulation, the MIMO detection method including generating a plurality of symbol vector sets and a plurality of search radiuses, selecting a candidate symbol vector set corresponding to a highest level of a multilevel structure of N-QAM constellation, generating a search space corresponding to a lower level of the multilevel structure of N-QAM constellation according to the selected candidate symbol vector set, confirming which level the search space corresponds to, and generating a detection signal according to the search space when the level of the search space is the lowest level of the multilevel structure of the N-QAM constellation.

Abstract: A method and apparatus for estimating attributes of a received signal that includes a plurality of transmitted signals are provided. The amplitude of the received signal is estimated by performing a method of demodulation based on known signal information. The amplitude of an M-ary quadrature amplitude modulated signal is estimated based upon known or ascertainable phase information regarding a plurality of transmitted symbols. The amplitude of a q-ary amplitude shift keyeing signal is estimated based upon known or ascertainable magnitude information regarding a plurality of transmitted symbols. Statistical information is also used for amplitude estimation.

Abstract: A method of processing an amplitude-modulated traffic signal involves the determination of a gain offset between the traffic signal and a reference signal, e.g., a pilot signal, received in association with the traffic signal, based on relating values known or determined from the reference signal to that gain offset. For example, in at least one embodiment of a wireless communication receiver, one or more processing circuits are configured to compute the gain offset based on the average magnitude of estimated traffic symbols and a signal-to-noise ratio. The received traffic symbols can be estimated using soft combining weights calculated from the reference signal, as can the signal-to-noise ratio. With the gain offset thus determined, the estimated traffic symbols can be scaled properly for subsequent processing, such as in log-likelihood ratio processing to recover the traffic signal data.

Abstract: A receiver is utilized to receive signals from various systems within a vehicle such as tire pressure monitoring system (TPM) and a remote keyless entry system (RKE). During the on time, the receiver sequentially is open to receive a first signal with a first baud rate. If the signal of the first baud rate is not received, the receiver receives a second signal at a second baud rate. Upon receipt of a transmission, the receiver operates according to a mode that corresponds to the transmission indicated by the specific baud rate. The operation of the receiver can include specialized filtering, or other known signal processing that is tailored to the specific transmission data communication requirements.

Abstract: Systems and methods of performing ASK or QAM modulation with uneven distance between symbols are provided. Different bit positions mapped to such symbols are assigned to different receivers, with the result that there are different BER performances among bits sent from a transmitter to the different receivers.

Abstract: Systems and methods of performing ASK or QAM modulation with uneven distance between symbols are provided. These are used to provide differing BER performances among bits sent from a transmitter to a receiver.

Abstract: An AM receiving circuit is disclosed which comprises an intermediate frequency amplifying unit that generates an intermediate frequency signal from a broadcast wave signal received by an antenna to amplify and output the intermediate frequency signal; an AGC (Automatic Gain Control) unit that sets gain of the intermediate frequency amplifying unit depending on electric field intensity of the broadcast wave signal; and an AM detecting unit that detects the intermediate frequency signal output from the intermediate frequency amplifying unit, wherein the AM receiving circuit comprises a sound quality compensating unit including: a filter unit that extracts a predetermined frequency band of the audio signal; an amplifying unit that boosts or attenuates the audio signal in the predetermined frequency band extracted from the filter unit; and a controlling unit that controls filter characteristics of the filter unit and sets a boosting function or an attenuating function of the amplifying unit, depending on the elec

Abstract: A device for providing a digital error signal, for a timing correction loop of a digital demodulator for digital transmission by phase modulation or amplitude and phase modulation, the device successively receiving pairs of digital signals representative of the components of complex signals, and having circuitry for providing a difference signal representative of the difference between the modulus of the complex signal corresponding to the last received pair of digital signals and the modulus of the complex signal corresponding to the previously-received pair of digital signals; circuitry for providing a weighting factor which depends on the angle between the complex signal corresponding to the last received pair of digital signals and the complex signal corresponding to the previously-received pair of digital signals; and circuitry for providing the error signal proportional to the product of the difference signal and of the weighting factor.

Abstract: A method and system is disclosed for providing an automatic gain control in signal processing. After receiving a stream of analog signals, a gain is adjusted on the received analog signals using a first set of gain compensation parameters. Then, the adjusted analog signals are converted to digital signals. A predetermined number of digital signals are collected from the converted digital signals within a predetermined time period. The collected digital signals are delayed from being transferred out for further demodulation processing for a predetermined delay time. At the same time, a second set of gain compensation parameters are estimated based on the collected digital signals. The estimated second set of gain compensation parameters are applied to the delayed digital signals.

Abstract: A method of demodulating a signal on which is modulated, using a quadrature amplitude modulation scheme, a plurality of information symbols, the method including: determining at least one QAM detection threshold corresponding to one or more of said information symbols; and demodulating each information symbol on the basis of at least one respective QAM detection threshold.

Abstract: In exemplary embodiments of the present invention, a degree of hierarchical modulation can be varied as a function of satellite position, which can be related to time of day, and where such hierarchical modulation can be a combination of phase and amplitude shifts. In exemplary embodiments of the present invention, as each satellite in a multiple satellite system broadcasting to North America moves towards a D-node or an A-node position, the offset angle of a phase-based hierarchical modulation scheme can be varied. Thus, in exemplary embodiments of the present invention, the lowest satellite position in the sky can have the lowest offset angle for overlay bits, which offset angle can, for example, progressively increase as the position of the satellite in the sky increases. At a satellite's highest point in the sky, the overlay offset angle can, for example, thus be at its maximum.

Abstract: Physical layer (PHY) sub-channel processing. A soft symbol decision stream is arranged into a number of sub-channels to reduce substantially the processing performed within a communication receiver on data that is not intended for that communication receiver. In other embodiments, a predetermined approach is employed to arrange the soft symbol decision stream into one or more frames; each frame may have one or more soft symbol blocks; and each soft symbol block may have one or more symbols. Each of the soft symbol blocks, within a frame, may be assigned to a sub-channel. Only the soft symbol blocks that contain information destined for the communication receiver need be decoded. Only the sub-channel that includes these soft symbol blocks, destined for this communication receiver, need be decoded. The soft symbol blocks not within the sub-channel may be discarded thereby recovering some of the processing capabilities of the communication receiver.

Abstract: In accordance with some embodiments, a communication system is described that comprises a soft-output detector configured to receive a transmit signal and output reliability information regarding the received signal. In accordance with such embodiments, the detector comprises a symbol combiner configured to operate in both a repetition mode and a non-repetition mode, wherein repetition mode comprises receiving a plurality of signals for the transmit signal.

Abstract: Serially concatenated convolutional coding (SCCC) transmitting ancillary data within DTV signals incorporates the ? trellis coding used for all DTV signals as its inner convolutional coding. The outer convolutional coding of the SCCC is subjected to _“anti-Gray”_ coding, either before or after its interleaving, but before its inner convolutional coding. In a receiver for ancillary data as so transmitted, simple logic circuitry recodes portions of the trellis decoded DTV signal containing soft decisions as to the symbol-interleaved convolutionally coded ancillary data to provide a Gray-code mapping of symbols to modulation levels. This recoding is done either before or after symbol de-interleaving, but before decoding the outer convolutional coding to recover ancillary data.

Abstract: A method and a corresponding transmitting device to encode data with a differential space-time block code. A code matrix is calculated recursively from a momentary data matrix with a previous code matrix as a DSTBC block with symbols that are to be transmitted, the data matrix is formed from at least two data symbols that are to be transmitted, and the amplitude is modulated. Amplitude modulation data is encoded into an amplitude difference of at least two data symbols within each individual DSTBC block.

Abstract: A wireless communication apparatus in a hierarchically coded modulation system can use error control mechanisms generated during decoding of base layer information to predict a probability of successful demodulation of enhancement layer information. Performance in the demodulation of the base layer correlates to performance in the demodulation of the enhancement layer. The receiver can determine whether to attempt demodulation of temporally correlated enhancement layer data based in part on the predicted probability of success. If the receiver determines not to demodulate the enhancement layer, the receiver can power down the enhancement layer demodulator, or otherwise minimize the power expended in the enhancement layer demodulator.

Abstract: Disclosed is a wireless communication system, more particularly, a receiver and a chipset for DSRC.

Abstract: A receiver and method for receiving and processing a sequence of transmitted symbols in a digital communication system utilizing soft pilot symbols. A set of soft pilot symbols are transmitted with higher reliability than the remaining symbols in the sequence by modulating the soft pilot symbols with a lower order modulation such as BPSK or QPSK while modulating the remaining symbols with a higher order modulation such as 16QAM or 64QAM. The receiver knows the modulation type and location (time/frequency/code) of the soft pilot symbols, and demodulates them first. The receiver uses the demodulated soft pilot symbols as known symbols to estimate parameters of the received radio signal. Unlike traditional fixed pilots, the soft pilots still carry some data. Additionally, the soft pilots are particularly helpful in establishing the amplitude reference essential in demodulating the higher order modulation symbols.

Abstract: Certain aspects of a method and system for independent in-phase (I) and quadrature (Q) loop amplitude control for quadrature generators may include determining an amplitude voltage associated with an in-phase (I) component and a quadrature (Q) component of a generated signal. A DC reference voltage associated with the I component and the Q component may be determined. The determined amplitude voltage may be compared with the determined reference voltage to generate a control signal. The amplitude mismatch between the I component and the Q component may be compensated by controlling a biasing current of one or more programmable buffers associated with one or both of the I component and the Q component, based on the generated control signal.

Abstract: Systems and methods are described for carrier phase synchronization for improved AM and TV broadcast reception. A method includes synchronizing the phase of a carrier frequency of a broadcast signal with the phase of a remote reference frequency. An apparatus includes a receiver to detect the phase of a reference signal; a phase comparator coupled to the reference signal-phase receiver; a voltage controlled oscillator coupled to the phase comparator; and a phase-controlled radio frequency output coupled to the voltage controlled oscillator.

Abstract: The present invention, takes advantage of the properties of quadrature signals to achieve precise quadrature alignment in a simple fashion. The expectation of the product of quadrature signals is zero. A phase error detection network therefore operates by multiplying the received quadrature signals and low-pass filtering the product to produce an error signal. When the signals are in precise quadrature relationship, the error signal will be zero. Real-time feedback control may be used to drive the error to zero. In accordance with another aspect of the invention, a variable phase shift network is achieved using a dual delay line. The difference in delay between the two delay lines is adjusted in response to the error signal to obtain precise quadrature alignment. The principles of the invention may be applied in connection with traditional mixer architectures or with switch-mode architectures.

Abstract: An improved receiver and method estimate one or more parameters, such as amplitude and signal-to-noise ratio, of a received signal, such as an M-QAM or q-ASK signal. The amplitude of an M-QAM signal is estimated based upon known or ascertainable phase information regarding a plurality of transmitted symbols. The amplitude of a q-ASK signal is estimated based upon known or ascertainable magnitude information regarding a plurality of transmitted symbols. In another embodiment, the amplitude of an M-QAM or q-ASK signal is estimated based on statistical knowledge of the amplitude of the transmitted symbols. Other embodiments estimate amplitude, noise power, and signal-to-noise ratio of a received signal utilizing second-order and fourth-order moments of received samples, a maximum likelihood searching process, or a Kurtosis estimation process.

Abstract: A communication apparatus includes a receiver may receive a signal including one or more frequencies associated with a symbol. The symbol may be any type of symbol such as a text telephone symbol encoded according to a cellular text telephone modem (CTM) protocol, for example. The receiver includes a demodulator unit that may be configured to determine the one or more the frequencies associated with the symbol and to generate a soft decision corresponding to the one or more frequencies. The soft decision may be based upon energies associated with the one or more frequencies.

Abstract: A method of demodulating digital data using M'ary QAM has been disclosed, comprising the steps of detecting a complex symbol vector D, establishing within which reference symbol boundaries the detected symbol vector D falls, the given reference symbol boundaries being associated with a complex reference vector R. Quadrature components (E_I and E_Q) of an error vector (E) constituting the difference between the detected vector D and the associated reference vector R are found and an error control signal (E?) as feed back signal in the demodulation stage is approximated. The influence of thermal noise in the receiver stage has been limited by a weighting and/or by noise balancing.

Abstract: An amplitude shift keying (ASK) demodulation circuit based on a self sample as a basis application in an organism implantation microsystem is a low-cost and high-performance ASK demodulation core, comprising a pulse shaper, a voltage scaler, a level contrastor, and a self-sampler for achievement of the demodulation core provided pretty digital features, and needs no passive resistor and capacitor, which may reduce the cost of design and prevent the problem with precision. Further, in the aspect of active point, the size of a transistor may be adjusted for variable control, and hence levels determined among modulation signals may be reduced to lower the complexity of voltage regulator in design.

Abstract: A low power (optionally, self-powered) integrated transceiver using on-chip antennas is provided. The transmitter and receiver utilize phase-locked loops (PLLs) which initially, in a closed-loop state, pre-tune (i.e. phase-lock) voltage controlled oscillators (VCOs) before opening the loops to allow them to transmit and receive data. The TX, in the opened-loop state, disables the loop components while (FM) modulating the VCO. The RX, in the opened-loop state, injection-locks the VCO with the incoming (FM) modulated signal while the remaining loop components serve to demodulate the signal. For both the TX and RX an integrated antenna can be used and, advantageously, the TX comprises a dual purpose inductor which functions as both an inductor in the voltage-controlled oscillator (i.e. in the resonant tank thereof) and the integrated antenna.

Abstract: Digital Transceiver (DTRX) usable in a radio communications systems for transmitting and receiving digital base-band signals, wherein the DTRX (300) comprises: at least one digital up-converter (DUC) (310) for transmitting digital base-band signals and at least one digital down-converter for receiving digital base-band signals. In one aspect of the teachings disclosed herein the DUC (310) comprises at least two over-sampling units (314, 315), at least one quadrature modulation unit (340), and at least one time-discrete sigma delta band-pass modulator (318). The digital down-converter comprises at least one quadrature demodulation unit (360), at least two decimator units (356,357), and at least two sub-sampling units (354, 355). The digital base-band signal comprises an in-phase component (I-signal) and a quadrature component (Q-signal).

Abstract: A method for concealing errors includes that the transmitting end splits the received compressed video data into slice structures, allocates the adjacent slice structures to non-adjacent OFDM sub-channels or sub-channel groups, and sends the slice structures to the receiving end; the receiving end conceals the errors on a slice structure according to the slice structure which is chronologically or spatially related to the erroneous slice structure if detecting that any error occurs on the slice structure. The transmitting end includes a slice splitting module and a frequency domain interleaving module; the receiving end includes a domain de-interleaving module, a decompression and error detecting module, and an error concealing module.

Abstract: A dual-use PLL frequency synthesizer for use in a transceiver is capable of operating as a local oscillation generator in a receiving mode and as a transmitter in a transmitting mode. The PLL frequency synthesizer includes a digital processor, a Digital-to-Analog Converter (DAC), a low pass filter and a phase locked loop. The digital processor generates a digital signal, in which the digital signal is a modulated digital signal in the transmitting mode, and the digital signal is a reference digital signal in the receiving mode. The DAC converts the digital signal to an analog signal, and the low pass filter filters the analog signal to produce a filtered analog signal. The phase locked loop up-converts the filtered analog signal to an RF signal. In the transmitting mode, the RF signal is a modulated RF signal, and in the receiving mode, the RF signal is a reference RF signal.

Abstract: A method for slicing a symbol in a QAM digital demodulator, includes acquiring a digital integer value by sampling a symbol signal in an in-phase coordinate or a quadrature-phase coordinate; and extracting a symbol bit sequence in the in-phase coordinate or the quadrature-phase coordinate from a whole bit sequence of the digital integer value by using an LSB thereof. Further, a symbol slicer for detecting a QAM symbol, includes digital sampling units, each of which acquires a digital integer value by sampling a symbol signal in an in-phase coordinate or a quadrature-phase coordinate; and a symbol bit sequence extracting unit that extracts a symbol bit sequence in the in-phase coordinate or the quadrature-phase coordinate from a whole bit sequence of the digital integer value by using an LSB thereof.