Abstract: An RF-to-IF converter includes radio frequency (RF) to intermediate frequency (IF) processing circuitry and a frequency synthesizer for generating a local oscillator signal and clocking signals. The frequency synthesizer includes a local oscillator (LO) output coupled to the processing circuitry, a baseband processor clock output, and clock generation circuitry for generating a baseband processor clock with a frequency of approximately 48 fo on the baseband processor clock output, where fo is 1.023 MHz.

Abstract: Disclosed is a method for acquiring synchronization in a mobile communication system using an Orthogonal Frequency Division Multiplexing (OFDM) scheme. The method includes modeling a power delay profile in time-varying frequency selective fading channel conditions by a specific function; detecting a log probability distribution function of a timing offset and a frequency offset in consideration of a correlation between a received signal and the received multi-path signal in the time-varying frequency selective fading channel conditions having the power delay profile modeled as the specific function; and estimating a timing offset and a frequency offset which maximize the log probability distribution function of the timing offset and the frequency offset.

Abstract: A receiver includes an input, a correlator, a phase-assisted demodulator, and an output. The input receives a modulated signal and the correlator generates a plurality of correlation values from the received modulated signal The phase-assisted demodulator, coupled to the correlator, selects one of the plurality of correlation values based on relative magnitude and relative phase information of at least a two of the plurality of correlation values. The output provides a demodulated signal, corresponding to the modulated signal, based on the selected one of the plurality of correlation values. The correlation value having the largest magnitude and the correlation value having the second largest magnitude is used in combination with the relative phase information of both correlation values in determining which correlation value corresponds to the correct demodulated symbol.

Abstract: An IS-OFDM system for point-to-point wireless communications that suppresses narrow-band interference comprises an IS-OFDM transmitter and an IS-OFDM receiver, wherein a transmitted signal comprises a plurality of subcarriers, and further wherein each subcarrier contains more than one and potentially all symbols transmitted in a given frame. The IS-OFDM transmitted signal is at a data rate that is equal to the data rate of the input data stream via the use of P/S converters.

Abstract: An integrated circuit operable to wirelessly communicate with other devices by utilizing a radio transceiver and a routing element is disclosed. The routing element is operable to route a signal between various circuit elements and is selectively operable to function as an antenna when coupled with the radio transceiver.

Abstract: A downconverter and upconverter are provided which can obtain a sufficient image rejection ratio in a low-Intermediate Frequency (IF) scheme while reducing power consumption and can suppress Error Vector Magnitude (EVM)-related degradation in a zero-IF scheme. A complex-coefficient transversal filter rejects one side of a positive or negative frequency, and converts a Radio Frequency (RF) signal to a complex RF signal configured by real and imaginary parts. A local oscillator outputs a real local signal with a set frequency. A half-complex mixer, connected to the complex-coefficient transversal filter and the local oscillator, performs a frequency conversion process by multiplying the complex RF signal output from the complex-coefficient transversal filter and the real local signal output from the local oscillator, and outputs a complex signal of a frequency separated by the set frequency from a frequency of the RF signal.

Abstract: In some embodiments, methods and apparatus to reduce nonlinearity in a receiver are generally described herein. Other embodiments may be described and claimed.

Abstract: A symbol detector for an OFDM receiver determines the correlation of corresponding samples of at least two received preamble symbol samples, one of the samples delayed a predetermined duration with respect to the other; determines a timing metric based on the correlation results; detects multiple peaks in the timing metric; indicates a symbol detection based on the multiple peaks detected in the timing metric; and gets a refined CFO estimation using averaging the phase information across these multiple peaks.

Abstract: Methods and systems for filtering an input signal include receiving a first demodulated signal produced by multiplying a first generated signal with a received input signal, receiving a second demodulated signal produced by multiplying a second generated signal with the received input signal, and producing first and second filtered output signals by applying a transfer function to the first and second demodulated signals, wherein the transfer function comprises a first filtering coefficient, wherein the first filtering coefficient defines a matrix comprising one or more non-symmetrical terms. An application of the transfer function can compensate for one or more of an amplitude mismatch between the first and second generated signals, a phase mismatch between the first and second generated signals, and one or more frequency handling characteristics of channels used to produce the first and second demodulated signals.

Abstract: A complex signal in which one of two signals that have been generated from a single real signal and that have phases that are shifted 90° with respect to each other is a real part and the other signal is an imaginary part is applied as input to an input terminal. A filter unit generates an output signal that is a complex signal by means of a convolution operation of the input signal, and a filter coefficient that is a real signal and supplies this output signal to an output terminal. A coefficient control unit made up from a common unit and separate units updates the filter coefficients such that the value of the envelope of the output signal approaches a target signal.

Abstract: The invention relates to a method for communicating digital data using an orthogonal frequency division multiplexing (OFDM) transmission system (10) including at least one transmitter (600, 601) and receivers (700, 701).

Abstract: A baseband processing module according to the present invention includes a multi-path scanner module. The multi-path scanner module is operable to receive timing and scrambling code information regarding an expected multi-path signal component of a WCDMA signal. Then, the multi-path scanner module is operable to identify a plurality of multi-path signal components of the WCDMA signal by descrambling, despreading and correlating a known symbol pattern of/with a baseband RX signal within a search window. The multi-path scanner module is operable to determine timing information for the plurality of multi-path signal components of the WCDMA signal found within the search window and to pass this information to a coupled rake receiver combiner module.

Abstract: A multirate digital transceiver in which, on reception, signals are simultaneously decimated and coarsely down converted in an iterative process to narrow down a received wideband to a desired channel and, on transmission, signals are interpolated iteratively to achieve a desired sample rate/band width.

Abstract: A received signal is sampled at a sampling period of T+m*(T/n) during a sampling phase determination process. T is a symbol or chip period of the received signal, n is a number of phases of the sampled signal, T/n is a phase resolution period, and m is a fixed non-zero integer value where ?n<m<n (e.g. m=1 or ?1). By sampling the received signal at the sampling period of T+m*(T/n), a sample set for each one of n phases of the sampled signal is produced. For each sample set, a correlation process is performed between the sample set and a predetermined correlation signal to produce a correlation result. Once an optimal correlation result is identified from the correlation process, the received signal is sampled at a sampling period of T at a phase associated with the optimal correlation result. Advantageously, oversampling at a sampling rate of n/T is not required during the sampling phase determination process, which reduces cost and power consumption.

Abstract: A slicer can receive a communication signal having a level or amplitude that is between two discrete levels of a multilevel digital communication scheme. The slicer can compare the communication signal to a plurality of references such that multiple comparisons proceed essentially in parallel. A summation node can add the results of the comparisons to provide an output signal set to one of the discrete levels. The slicer can process the communication signal and provide the output signal on a symbol-by-symbol basis. A decision feedback equalizer (“DFE”) can comprise the slicer. A feedback circuit of the DFE can delay and scale the output signal and apply the delayed and scaled signal to the communication signal to reduce intersymbol interference (“ISI”).

Abstract: A spread spectrum signal demodulating method whereby spread-code synchronous acquisition and carrier synchronous acquisition are performed using FFT at high speed, wherein a received signal, of which the carrier wave is modulated with a signal obtained by spectrum-spreading data with a spread code, is subjected to the FFT and the result of the FFT is stored in a first memory. The FFT result of the received signal stored in the first memory and the result of FFT of the spread code stored in a second memory are read out and multiplied to detect the correlation between the received signal and the spread code. A readout address of either the FFT result of the received signal or the FFT result of the spread code is shifted by an amount corresponding to a carrier frequency of the received signal.

Abstract: A system, method, and apparatus for a multiple data rate communication system is presented herein. The communication system receives data samples that are either sampled at a narrowband rate or a wideband rate and provides various functions and services, such as echo cancellation, DTMF detection and generation, and call discrimination. For wideband signals, a down-sampled signal is provided for each of the foregoing function and service. The output of the function or services is then recombined with the wideband signal.

Abstract: A symbol timing estimation method is provided for use in a communication system, for example an orthogonal frequency division multiplexing system having a cyclic prefix extension CPE. Each symbol in a transmitted signal comprises N symbol samples, and the CPE has L symbol samples. The method comprises receiving the signal and processing the symbol samples in the received signal using N and L to obtain a correlation function ?(d) for a first series of L samples and a second series of L samples following N samples after the first series. The obtained correlation function is normalized to produce a basic measure MCP(d) for symbol timing estimation. A second-derivative measure MCP—diff2(d) for symbol timing estimation is also produced based on a second derivative of the basic measure, and the symbol timing is estimated based on the basic and second-derivative measures.

Abstract: A method includes the steps of receiving a signal indicative of data bits, and performing per survivor processing-iterative timing recovery (PSP-ITR) on the received signal to generate probabilities of the data bits. To perform PSP-ITR on the received signal, the signal can be processed using a per survivor processing-soft decision algorithm (PSP-SDA) which jointly performs timing recovery and equalization in accordance with embodiments of the present invention. The soft decision algorithm (SDA) can be, for example, a Bahl, Cocke, Jelinek, and Raviv (BCJR) algorithm or a Soft Output Viterbi Algorithm (SOVA) modified in accordance with the concepts of the present invention such that it is configured to implement per survivor processing (PSP) to jointly perform timing recovery and equalization.

Abstract: A method and system of improving sensitivity in the demodulation of a received signal over an arbitrary measurement time epoch, the method comprising the steps of: correlating the received signal in a coherent fashion (80); and utilizing a Viterbi phase state keying trellis demodulation with a variable resolution of phase states over 360° to demodulate the radio frequency phase trajectory of the signal throughout the measurement time epoch (70); and the system comprising a receiver for receiving a direct sequence spread spectrum signal, the receiver comprising: an antenna (10) for receiving the direct sequence spread spectrum signal; a downconverter (40) for downconverting the received signal, producing a downconverted signal; an analog to digital converter (60) to convert the downconverted signal to a digital signal; a despreader (80) for despreading and coherently correlating the digital signal to a known signal, creating a despread signal; and a processor (70) for applying a Viterbi algorithm to the despre

Abstract: The invention relates to a method for establishing an at least partially wireless data transfer connection between a remote application and a controlling application. The wireless connection is implemented by a wireless terminal connected to the remote application. The wireless terminal can select from a group of allowable connection parameter settings a usable connection parameter setting for the wireless link, if a default connection parameter setting for the wireless link is not usable. The invention relates also to a wireless terminal using the method and a computer program implementing the method in the wireless terminal.

Abstract: Methods and apparatuses for blind equalizers with a hybrid adaptation error. In one embodiment, a Quadrature Amplitude Modulation (QAM) signal receiver, includes: a filter to reduce error in equalization, the filter to output a QAM signal; a decision engine coupled to the filter to determine a symbol based on the QAM signal; a first error generator coupled to the filter to compute a first error signal based on the QAM signal and a constant; a second error generator coupled to the filter and the decision engine to compute a second error signal based on the QAM signal and the determined symbol; an error combinator coupled to the first and second error generators to generate a combined error signal from the first and second error signals; and an adaptation engine coupled with the error combinator and the filter to reduce a equalization error according to the combined error signal.

Abstract: The present invention is a quadrature multi-mode RF receiver that uses a single quadrature mixer for tuning to desired frequency bands. In a direct conversion mode of operation, the RF receiver down converts a received RF signal directly into a baseband signal. In a VLIF mode of operation, the RF receiver down converts a received RF signal into a VLIF signal. When receiving a wanted RF signal, the frequency of the resulting VLIF signal is called the wanted VLIF frequency, and is based on the signal strength of the received RF signal. In one embodiment of the present invention, the wanted VLIF frequency is selected to be one of two VLIF frequencies. The wanted VLIF frequency is inversely related to the signal strength of the received RF signal.

Abstract: An apparatus and method for controlling a transmission mode in a MIMO mobile communication system are provided. In a receiver in the MIMO mobile communication system, an error checker checks errors in received data and outputting an error check result. A feedback portion adaptively changes a threshold associated with a channel state according to the error check result, and determines a transmission mode by comparing the changed threshold with a measured CQI, and feeds back transmission mode information to a transmitter.

Abstract: A joint synchronizer and decoder that implements two decision aided processes, which are referred to as “decision aided candidate selection” and “decision aided synchronization and decoding.” Decision aided candidate selection may be used to select a carrier frequency offset by selecting among a number of candidates for this parameter based on an indication of decoding success. Decision aided synchronization and decoding may be used for phase tracking based on an indication of decoding success. Although these joint synchronizing and decoding techniques may be implemented together, they may also be implemented independently. The joint synchronizer and decoder may be implemented within a return channel receiver in a DVB-RCS system using turbo coding and quadrature phase shift key (QPSK) data modulation.

Abstract: A high frequency signal detection circuit includes an input terminal for a high frequency signal to be detected, a switch transferring the high frequency signal as intermittent ringing signal to a first node in response to a pulse signal whose frequency is lower than that of the high frequency signal, a transistor amplifying the signal at the first node, and outputting to a second node, a bias generator generating a bias voltage by which the transistor is operated in its weak inversion region, a resonant circuit outputting the bias voltage to the first node, and resonating the high frequency signal, a capacitor removing a high frequency component of the signal at the second node; and a judgment circuit judging whether or not the high frequency signal is inputted by detecting the signal at the second node, which has the same frequency as the pulse signal.

Abstract: A hybrid carrier frequency offset estimator that uses data-aided and non-data-aided signal processing techniques to produce multiple candidates for the carrier frequency offset within a return channel receiver in a DVB-RCS system using turbo coding and quadrature phase shift keying (QPSK) data modulation. In this system, the invention is employed to estimate signal distortion caused by carrier frequency offset so that this particular source of signal distortion can be removed to improve the ability of the receiver to maintain synchronization in low signal-to-noise conditions. This, in turn, allows the receiver to meet the DVB-RCS performance target, measured in terms of packet loss ratio, in low signal-to-noise ratio conditions and in particular for burst-mode data transmission with a short data packet size.

Abstract: A frequency recovery apparatus and a mobile broadcast reception system utilizing the frequency recovery apparatus are disclosed. The frequency recovery apparatus and the mobile broadcast receiver estimate a fractional frequency offset value using I and Q components of a correlation value of a guard interval and compensate for the estimated fractional frequency offset value, resulting in the implementation of correct and rapid acquisition characteristics. The feedback-structured fractional carrier recovery apparatus estimates a fractional frequency offset, and compensates for the estimated fractional frequency offset, such that it solves the problem of ambiguity which may occur in a specific position corresponding to 0.5 times a sub-carrier spacing, and the fractional frequency offset can be stably estimated or compensated for.

Abstract: In a soft decision method for demodulation of a received square QAM (Quadrature Amplitude Modulation) signal, the processing speed is improved, and the manufacturing expense is reduced, by using condition probability vector values, which are soft decision values. A condition judgment operation is employed.

Abstract: Timing correction is affected for mismatch between channels in an I/Q demodulator. The respective demodulated I-channel and Q-channel are correlated and integrated so generate a timing control signal that is applied to a variable delay element. The variable delay element inserts a variable time delay in an ADC clock signal that is applied to either the I-channel ADC or the Q-channel ADC.

Abstract: An embedded multimedia system for playing analog and digital audio broadcasting signals includes an antenna for receiving analog and digital audio broadcasting signals, an audio output device for outputting sound, an analog demodulator for demodulating analog audio broadcasting signals for the audio output device, and a digital demodulator for conducting a signal connection between the antenna and the analog demodulator, or transforming digital audio broadcasting signals into analog audio broadcasting signals for the analog demodulator.

Abstract: A semiconductor circuit device is provided which can attain more stable operations against noise in a data communication system without increasing the power consumption of an overall system, thereby improving the reliability of data communication. For a demodulation baseband signal (S11) obtained by performing digital processing on an output signal (S6) from an AD converter (6), the maximum value (S12) and the minimum value (S13) are detected as digital values by a maximum value holding circuit (11) and a minimum value holding circuit (12), an averaging circuit (13) obtains an average value (intermediate value) of the maximum value and the minimum value and detects a frequency offset amount (S14), and the frequency offset amount is fed back to a threshold value of data decision (14), so that binarized demodulation data (S15) is outputted in which the offset of the demodulation baseband signal is corrected.

Abstract: Systems and methods for maintaining synchronization of a base unit and a portable unit in a low-power mode are provided. The base unit and the portable unit communicate with each other via wireless frequency hopping radio communications links. The base unit and the portable unit switch to a synchronization state in a synchronization period during the low-power mode. During the synchronization period, the base unit transmits one of a first and a second link synchronization messages. The portable unit is required to respond to the second link synchronization. If the base unit receives a response from the portable unit within a predetermined number of periods, the base unit and the portable unit switch back to the low-power mode. Otherwise, the base unit and the portable unit are switched to a SEARCH state to search for a synchronized communications channel.

Abstract: A digital mixer system and method is disclosed. In an embodiment, a digital mixer can receive a modulated signal having a sample rate approximately equal to a clock rate divided by an integer factor. The digital mixer can include a first mixing stage having a first plurality of Coordinate Rotation Digital Computer (CORDIC) elements to serially perform a predetermined number of consecutive CORDIC iterations per clock cycle. The first mixing stage can further have logic to selectively process data received from an output of the first mixing stage. The digital mixer can also include a second mixing stage having a second plurality of CORDIC elements to serially perform a number of consecutive CORDIC iterations per clock cycle. The second mixing stage can also have logic to selectively process data received from an output of the first mixing stage and from an output of the second mixing stage.

Abstract: A receiver having a frequency-deviation detector which includes: a storage for locating and storing the frequency-domain symbol-signal in a two-dimensional data area on a two-dimensional space corresponding to a carrier frequency and a symbol time; a calculator for calculating the transfer characteristic of a pilot signal; a Fourier transformer for performing two-dimensional Fourier transform on the calculated characteristic to locate the data group after the transform in a two-dimensional Fourier transform data area corresponding to a transmission delay time and path fluctuation frequency; and a calculation portion for calculating the frequency deviation based on the center-of-gravity value.

Abstract: An FM modulation signal is mixed with a pair of first local oscillation signals to be converted to a pair of base band signals. The base band signals are respectively mixed a pair of second local oscillation signals. The resultant signals are added together, thereby yielding an IF signal which is in turn detected. The local oscillator generates a reference oscillation signal whose frequency corresponds to a carrier component of the IF signal and frequency-divides the reference oscillation signal, thus generating the second local oscillation signals. The frequency of the first local oscillation signal converges to the one that has a given ratio to the frequency of the reference oscillation signal.

Abstract: A quadrature voltage controlled oscillator includes oscillation circuits for generating in-phase and quadrature-phase oscillation signals that are used to generate in-phase and quadrature-phase output signals. A compensation circuit adjusts biasing in the oscillation circuits depending on a phase relationship between the in-phase and quadrature-phase output signals to automatically control the phase relationship between the oscillation signals.

Abstract: An apparatus and method of an OFDM system for compensating IQ imbalance. The apparatus includes a mixer module for mixing a wireless signal to generate a pair of in-phase and quadrature-phase analog signals; an in-phase and quadrature-phase imbalance parameter estimation unit coupled to the mixer module for estimating a gain compensation value and a phase compensation value; and a signal compensation module coupled to the in-phase and quadrature-phase imbalance parameter estimation unit for compensating the pair of in-phase and quadrature-phase analog signals for gain imbalance and phase imbalance, according to the gain compensation value and the phase compensation value respectively.

Abstract: A system comprises a receiver module that receives a signal that is modulated using coherent orthogonal frequency division multiplexing (OFDM) modulation. A signal to noise ratio (SNR) module communicates with the receiver module and generates a SNR estimate based on the OFDM signal. An estimator module communicates with the SNR module and estimates carder frequency offset (CFO) based on the SNR estimate. System for orthogonal frequency division multiplexing (OFDM) signals such as frequency differential demodulation and time differential demodulation are also described.

Abstract: In a data carrier (1) which includes receiving means (5) for receiving a modulated carrier signal (MTS) which contains a data signal (DS1) encoded in conformity with an encoding method (MA, PW, MI, RTZ, FSK, PSK), demodulation means (9) for demodulating the received modulated carrier signal (MTS) and for outputting the encoded data signal (DS1) contained therein, decoding means (10, 20) for decoding the encoded data signal (DS1) and for outputting data (D1, D2), and data processing means (11) for processing the data (D1, D2) output by the decoding means (10, 20), the decoding means (10, 20) are provided with at least a first decoding stage (12) and a second decoding stage (13), the first decoding stage (12) being arranged to decode a data signal (DS1) encoded in conformity with a first method (RTZ) whereas the second decoding stage (13) is arranged to decode a data signal (DS1) encoded in conformity with a second method (MI).

Abstract: A method for calculating zero-crossing reference sequences ({ti}) for the data detection of a sequence of zero crossings ({{circumflex over (t)}i}) of a received signal is disclosed. The data detection is determined in a receiver, wherein the received signal is based on a data symbol sequence ({dk}) angle-modulated at a transmitter and transmitted to the receiver. The zero-crossing reference sequences ({ti}) are calculated in accordance with an equation specifying an output of a finite state machine that describes, at least approximately, the signal generation in the transmitter.

Abstract: A method of simultaneously determining a DC offset and a channel impulse response from a received signal in a mobile communication system. The received signal Y comprising a set of training sequence bits that have been modulated prior to transmission. The modulated signals experience a certain phase shift and are rotated by a certain angle. The received signal may also comprise a DC offset component ADC that needs to be removed. By manipulation of the received signal samples with the knowledge of the original training sequence TRS and method of modulation used, it is possible to simultaneously estimate the communication channel's impulse response H and the DC offset ADC by finding the Least Square solution to a linear equation, such that the energy of the noise term introduced into the communication channel may be kept to a minimum.

Abstract: AM receiver 20 is provided with antenna 1, RF amplifier 2, I/Q mixer 3, VCO 4, impulse noise detector 5, interpolator 6, BPF 7, IF amplifier 8 and AM detector 9. I/Q mixer 3 is composed of I mixer 11a as an in-phase mixer and Q mixer 11b as an orthogonal mixer. Impulse noise detector 5 generates an interpolation signal from in-phase and orthogonal output signals from I/Q mixer 3. Interpolator 6 carries out shaping of waveforms of the output signals from I/Q mixer 3 in response to the interpolation signal and eliminates impulse noises from the output signals from I/Q mixer 3.

Abstract: A demodulation apparatus that can support various oscillation frequencies. The portable phone device includes a frequency synthesizer for generating a local-oscillation signal having a local oscillation frequency for converting the frequency of an input receiving signal into an intermediate frequency based on an oscillation signal generated by an TCXO and a synchronization hold portion provided with an NCO for generating a signal having a predetermined frequency based on the oscillation signal generated by TCXO. The frequency synthesizer makes the local oscillation frequency variable by setting the dividing ratio variable in accordance with an arbitrary oscillation frequency so that the intermediate frequency remains within a predetermined range regardless of the oscillation frequency, and an NCO makes the frequency of the signal variable by setting the dividing ration variable in accordance with the oscillation frequency.

Abstract: Multi-symbol non-coherent continuous phase modulation (CPM) detectors having a trellis structure, methods of continuous phase detection using a trellis structure, and trellis-based lock detectors and methods for digitally modulated signals are described. The continuous phase modulation detector includes receiver, observation, memory, and adjustment portions. The receiver has a trellis structure and is adapted for receiving digitally modulated signals having a generally continuous phase. The observation portion is adapted for performing multi-symbol observations on received digitally modulated signals and the memory is adapted for storing historic observation data corresponding to multi-symbol observations performed by the observation portion. The adjustment portion is adapted for selectively adjusting the receiver in accordance with stored historic observation data.

Abstract: A communication system including a transmitter, a receiver, and a TMDS-like link, in which video data and auxiliary data (typically including timing data associated with other auxiliary data) are transmitted from the transmitter to the receiver, or in which video data are transmitted over the link from the transmitter to the receiver, and auxiliary data (typically including timing data associated with other auxiliary data) are transmitted from the receiver to the transmitter. In typical embodiments the auxiliary data include one or more streams of audio data.

Abstract: There is provided a detector for extracting binary data frequency-modulated on a carrier signal. An axes generator produces M pairs of logic signals, the logic signals of the same pair being in quadrature. The decoder includes M asynchronous logic zero-crossing detectors producing first pulses and second pulses. An up-counter/down-counter has first, second and third values, and when it has the second value, passing to the first value during a first pulse, and passing to the third value during a second pulse, and a binary decoder generates binary data whose state is not modified when the up-counter/down-counter passes from the first value to the second value or from the third value to the second value. No external time base is required and the decoder has a reduced bit error ratio.

Abstract: A method and a standard radio wave receiver for receiving a plurality of standard radio waves respectively having signal configurations in accordance with respective specifications which define carrier channels and formats and for decoding time code signals carried by the standard radio waves. The method extracts at least part of a bit waveform common to the specifications as a extracted signal from a waveform of each of the time code signals given by each of the carrier channels, synchronizes bits to each of the time code signals in accordance with the extracted signal, determines an evaluation index indicating good or bad of a reception condition for each of the carrier channels from the bit waveform, and selects a single channel from the carrier channels in accordance with the evaluation index.

Abstract: A system and method of detecting Automatic Identification System (AIS) signals in space and decoding these signals. In one aspect, a system for performing this function is described which includes a receiver configured to receive the plurality of AIS signals and pre-process the plurality of AIS signals to produce digital input data, and a processor configured to process the digital input data to identify one or more candidate AIS message signals based on Doppler offsets associated with the digital input data, determine corresponding Doppler offset estimates and time estimates of the one or more candidate AIS message signals, decollide and decode the one or more candidate AIS message signals to obtain corresponding message segments and validate the decoded message segments for proper AIS formatting.

Abstract: In one embodiment, the present invention includes a digital mixer to receive and digitally mix incoming weather band radio data with a control signal, a digital demodulator to demodulate the data to obtain a demodulated signal, and a digital feedback loop coupled between the demodulator and the digital mixer. The digital feedback loop includes a loop filter to receive the demodulated signal and to generate a filtered output and a fine tune controller to receive the filtered output and a frequency control signal and to generate the control signal based on them. In this way, audible artifacts caused by a frequency step change occurring in an analog front end to which the digital circuitry is coupled can be reduced or removed.