Abstract: A system and method for performing frame and symbol timing synchronization on samples of a received signal that includes a series of frames. Each frame includes a known preamble and payload data. A start-of-frame time is estimated by scanning the received signal samples for the self similarity of two successive preambles. A carrier frequency offset (CFO) is estimated by maximizing a correlation between a magnitude spectrum of the received signal and a magnitude spectrum of a known preamble model. A fine estimate for the CFO is determined by computing a phase difference between samples separated by p repetitions of the base pattern for various values of index p, and computing a slope of a least squares affine fit to the phase differences. Additional operations are performed to find an optimal symbol starting point, to perform carrier phase synchronization and to detect the start of payload data.

Abstract: Disclosed herein are methods and techniques for reducing phase slips in optical communications systems and in particular methods and techniques that operate in receivers for a coherent communication system transmitting modulated data symbols exhibiting N-ary symmetrical constellation and predetermined reference symbols.

Abstract: A method is provided for synchronizing binary data transmitted in parallel via N channels. The method comprises performing at the receiver side, a data-clock-alignment for the data in the N channels by selecting an optimal reference channel to which no delay will be added, and adding an appropriate delay to each of the remaining channels, until their respective centers of valid data portions are aligned to each other, and associating clock edges with the centers of the valid data portions. The method is characterized in that the alignment is performed regardless to whether binary word alignment is simultaneously achieved or not, and wherein the optimal reference channel allows aligning the centers of valid data of all the channels while adding a minimal delay to a worst channel from among the remaining channels, wherein the worst channel carries valid data portions which are maximally shifted from those of the reference channel.

Abstract: A receiver and method for a transponder of a two-way automatic communications system (TWACS) used by an electrical utility in which analog outbound messages are sent from the utility to a consumer and inbound, reply messages are sent from the consumer to the utility. The receiver and method enable a transponder to detect the outbound messages and include A/D conversion and digital processing for demodulating a digitized signal and providing the outbound message.

Abstract: A communication apparatus including: a transmitter that transmits a first message to another communication apparatus, a receiver that receives a second message from the other communication apparatus, and a processor that performs time synchronization using the first message and the second message, wherein the processor generates information regarding a delay in the communication processing of the first message in the transmitter and the second message in the receiver in a communication layer in communication with the other communication apparatus, and the processor performs the time synchronization with the other communication apparatus based on the information regarding the delay in a time synchronization layer above the communication layer.

Abstract: Symbol timing acquisition is described for a wireless broadband signal received at a user terminal from a gateway via a satellite. In-phase and quadrature channels of the wireless signal may each be sampled at a rate of one sample per symbol. The samples may be interpolated to generate an early interpolation and a late interpolation for each of the samples. A difference measurement is obtained between the early interpolation and the late interpolation for a set of the samples. A number of the difference measurements may be averaged, and symbol timing may be modified based on the average. This process may be continued on an iterative basis to acquire symbol timing.

Abstract: Disclosed are various embodiments for circuitry that generates a sync code for wireless transmission. The system generates a sync word according to an identifier of the transmitter, the sync word being unique under a cyclic shift of the sync word. The system inserts a plurality of instances of the sync word into a data stream. The system also transmits, via the transmitter, the data stream to a receiver, the receiver being operable to perform a sliding correlation operation on the sync word.

Abstract: A transmission system which couples a plurality of transmission devices to a control device includes a first transmission device which is one of the plurality of transmission devices; a first calculation circuit which calculates a first difference value indicating a frequency difference value between a common clock supplied from the control device and a first clock as a clock used in the first transmission device; and a transmitter which reports the first difference value to a second transmission device other than the first transmission device, wherein the second transmission device comprises: a second calculation circuit which calculates a second difference value indicating a frequency difference value between the common clock and a second clock used in the second transmission device, and a frequency controller which controls an oscillator generating the second clock so that the second difference value approaches the first difference value reported from the first transmission device.

Abstract: A transmitting apparatus transmits signals in a digital telecommunication system and a synchronising method is used for synchronizing such signals at a receiving apparatus. The transmitting apparatus prepares for transmission a reference symbol having at least two repetition patterns, whereby one of the at least two repetition patterns is phase-shifted in relation to the other repetition pattern, and a synchronizing mechanism in the digital telecommunication system uses the reference symbol once received for synchronization. The synchronizing mechanism uses a cross-correlation mechanism to cross-correlate at least one of the two repetition patterns within a correlation window having a predetermined length.

Abstract: Methods and circuits for controlling an automatic gain control (AGC) circuit wherein the AGC circuit is used to adjust the gain of a signal input to an analog to digital converter. The method includes obtaining a plurality of samples from the output of the analog to digital converter and determining whether the amplitude of each sample is greater than a threshold amplitude value. If the amplitude of a sample is greater than the threshold amplitude value then a counter value is incremented. The target average amplitude of the automatic gain control circuit is then periodically adjusted based on the counter value.

Abstract: A signal transmission apparatus includes: a vertical rectangular region sampling-out control section that obtains vertical rectangular regions, repeatedly performs a process where pixel samples read out from each line of class images are mapped to each line of video data regions of sub-images, maps pixel samples to each line of the video data regions, and repeatedly maps pixel samples to the next line; a line sampling-out control section that samples out the pixel samples every other line from each line of the sub-images to which the pixel samples have been mapped, so as to generate an interlace signal; a word sampling-out control section that samples out for each word the pixel samples which have been sampled out for each line so as to be mapped to video data regions of an HD-SDI prescribed by the SMPTE 435-2; and a readout control section that outputs the HD-SDI.

Abstract: In a particular embodiment, a method includes receiving a first portion of a sync field of a packet at a receiver. The sync field includes the first portion and a second portion. The packet includes the sync field and a payload field. The method includes detecting a sync word associated with the packet. The sync word is detected based on the first portion of the sync field and prior to receiving the second portion of the sync field. The method initiates a demodulation stage of the receiver prior to receiving an initial bit of the payload field. Initiating the demodulation stage prior to receipt of the initial bit of the payload field enables a demodulator to perform initial demodulation activity prior to demodulation of the payload field. Demodulation continues if, after the second portion is received, the entire received sync field matches the detected sync word.

Abstract: A wireless receiver designed to conform to the standard IEEE 802.15.4. The receiver comprises an analog front-end and a digital decoder. The analog components of the front end include one or more amplifiers and an analog-to-digital converter (ADC). The digital decoder receives the output of the ADC and demodulates it in a demodulator which is driven at an a chip frequency by an internal or external clock. The demodulator comprises a sampler operable to sample the digital signal at a sampling frequency and a correlation unit operable to process a set of bits, referred to as a chip code, in the sampled digitized signal and output therefrom a set of correlation values. The set of correlation values is an indicator of likely mapping between the chip code that has been processed and a set of possible chip codes defined according to the standard. The demodulator further comprises a symbol selection unit and a frequency correction unit.

Abstract: In one embodiment, a method includes determining pre-calculated information. The pre-calculated information is used to determine a counter pattern for a reference clock. The counter pattern include, for at least one data bit, a number of reference clock cycles of the reference clock that is determined based on a frequency of the reference clock and a data rate of a serial data stream. The serial data stream is sampled to read a plurality of data bits based on the counter pattern. A data bit is sampled based on the number of reference clock cycles associated with the data bit.

Abstract: A method and a device for time synchronization are disclosed according to the embodiments of the present invention. The method includes: selecting, by a slave device, a port of a single-fiber bi-directional line as a synchronization port of a 1588 clock protocol; specifying a work mode of the synchronization port; exchanging a 1588 clock synchronization packet with a master device through the synchronization port according to the work mode; acquiring transmission time information and restore a system clock according to the 1588 clock synchronization packet; and adjusting the system clock according to the work mode and the transmission time information. The device includes: a line processing module, a clock recovery module and a clock adjustment module. Through the method and the device, zero-error time synchronization is implemented; and in the case of unfixed path delay, the time synchronization can also be implemented.

Abstract: Provided are a method for dynamically acquiring a PN synchronization of a blink signal in a reader according to a channel state when a tag transmits a direct sequence spread spectrum (DSSS) blink signal having a predetermined period and the reader receives the blink signal in a 2.4 GHz RTLS system which complies with an ISO/IEC24730-2 standard, and a method for synchronizing a frame using a preamble.

Abstract: Devices, methods, and other embodiments associated with phase based preamble detection are described. In one embodiment, an apparatus includes a wireless transceiver, an evaluation logic, and a configuration logic. The wireless transceiver receives a wireless signal from a wireless device. The wireless signal includes a preamble sequence. The evaluation logic evaluates the preamble sequence by comparing phases of the preamble sequence to phases of predefined preamble sequences to identify a matching preamble sequence. The comparison is done without using amplitude information. The configuration logic configures the wireless transceiver to synchronize wireless communications with the wireless device based, at least in part, on the matching preamble sequence.

Abstract: Various aspects of an approach for acquiring sequences such as balanced Hamming weight preamble sequences are described herein. The approach provides for the acquisition of preamble sequences base on energy accumulation. The approach includes creating a plurality of synchronization hypotheses, with each hypothesis being created based on energies sampled at a first location and a second location in a plurality of locations associated with a sequence of transmitted symbols; calculating a plurality of metrics based on the plurality of synchronization hypotheses, wherein each metric is associated with a hypothesis; selecting, as a candidate, one hypothesis from the plurality of synchronization hypotheses including a maximum associated metric. The approach may further include determining a boundary in the sequence of transmitted symbols based on a correlation property of the sequence of transmitted symbols.

Abstract: Disclosed is an apparatus and method for detecting a code. The code detecting apparatus may include a detector to detect symbol synchronous timing information associated with a PSS code from a first signal received during a predetermined first period, a compensator to extract and buffer the PSS code and the SSS code based on the symbol synchronous timing information detected from a second signal received during a predetermined second period, and compensate for a frequency offset with respect to the buffered PSS code, and a processor to re-detect the symbol synchronous timing information based on the PSS code in which the frequency offset is compensated for, and extract the buffered SSS code using the re-detected symbol synchronous timing information.

Abstract: Apparatus for processing broadband impulses signals of low repetition rate includes a tuner for receiving broadband impulsive signals of low repetition rate and providing an output signal characteristic of the amplitude and spectral content of the received input signal. Resolution bandwidth filters coupled to the tuner output each have a different bandwidth that determines the measurement resolution and influences the sensitivity and transient response to low repetition rate impulsive signals. At least one radio frequency switch selects a resolution bandwidth filter for coupling to and associated one of at least a peak detector, an average detector and an envelope generator. A gate generator coupled to the peak detector, the average detector and the envelope generator furnishes a gating signal to each to provide a peak signal, an average signal and an envelope signal respectively during a selected gating interval. A microprocessor is coupled to the peak detector and the average detector.

Abstract: A duty cycle correcting device is provided which includes a pulse width adjusting unit which adjusts a pulse width of an input signal according to a pulse width control code; a comparison unit which compares an output signal of the pulse width control unit with a plurality of reference voltages; and a control unit which selects one of a plurality of pulse width control codes based on comparison data from the comparison unit and provides the selected pulse width control code to the pulse width adjusting unit.

Abstract: An OFDM frame synchronisation method in which the symbols of the preamble carry a code. The detection of the code allows the frame synchronization in presence of low SNR.

Abstract: A method of frame sync detection is described. A first and second differential correlation of a data stream is calculated, at a plurality of delay and conjugate multipliers. The first and second differential correlations are convolved with a previous set of differential correlations. A correlation peak is calculated, at a sync detector, using the convolved differential correlations, to detect a frame sync.

Abstract: Techniques for transmitting pilot and for processing received pilot to obtain channel and interference estimates are described. A terminal may generate pilot symbols for a first cluster in a time frequency block based on a first sequence and may generate pilot symbols for a second cluster in the time frequency block based on a second sequence. The first and second sequences may include common elements arranged in different orders and may be considered as different versions of a single sequence. The terminal may transmit the pilot symbols in their respective clusters. A base station may obtain received pilot symbols from multiple clusters in the time frequency block. The base station may form each of multiple basis vectors with multiple versions of the sequence assigned to the terminal and may process the received pilot symbols with the multiple basis vectors to obtain a channel estimate for the terminal.

Abstract: A system including a demodulation module, a metric generation module, and a preamble detection module. The demodulation module is configured to generate demodulated signals based on demodulating, in accordance with a differential demodulation scheme, signals received from a base station. The signals received from the base station include a plurality of symbols. The demodulated signals comprise a plurality of real parts each having a corresponding magnitude. The metric generation module is configured to generate a plurality of metrics for the plurality of symbols based on the corresponding magnitudes of the plurality of real parts of the demodulated signals. The preamble detection module is configured to detect, based on the plurality of metrics, whether the plurality of symbols in the signals received from the base station includes a preamble symbol.

Abstract: A transmission apparatus includes a plurality of orthogonal frequency division multiplexing (OFDM) modulation signal generators, which generate a first OFDM modulation signal and a second OFDM modulation signal. The transmission apparatus also includes a transmitter that transmits the first OFDM modulation signal from a first antenna and the second OFDM modulation signal from a second antenna, in an identical frequency band.

Abstract: A system and method for performing frame and symbol timing synchronization on samples of a received signal that includes a series of frames. Each frame includes a known preamble and payload data. A start-of-frame time is estimated by scanning the received signal samples for the self similarity of two successive preambles. A carrier frequency offset (CFO) is estimated by maximizing a correlation between a magnitude spectrum of the received signal and a magnitude spectrum of a known preamble model. A fine estimate for the CFO is determined by computing a phase difference between samples separated by p repetitions of the base pattern for various values of index p, and computing a slope of a least squares affine fit to the phase differences. Additional operations are performed to find an optimal symbol starting point, to perform carrier phase synchronization and to detect the start of payload data.

Abstract: A video transmission method is provided, which includes receiving state information from at least one mobile terminal that intends to perform a video stream service through a wireless network, determining a size of an image by selecting a specified spatial layer bit stream on the basis of the state information of the mobile terminal from a plurality of spatial layer bit streams generated at different bit rates during encoding of the bit stream, selecting a specified time and an SNR layer bit stream by increasing or decreasing time of the image and a layer position of the SNR layer bit stream on the basis of network parameters included in the state information of the mobile terminal, and transmitting the bit stream generated by extracting the specified layer bit stream of the selected layer to the mobile terminal.

Abstract: The present invention relates to a method and apparatus for code acquisition. The present invention performs variable delay correlation to obtain the peak correlation result which is immune to carrier frequency offset and Doppler. The present invention makes use of a mapping parameter which is immune to sampling frequency offset. In particular, the present invention is applicable to the DTMB standard.

Abstract: A synchronization method for impulse system ultra-wideband takes frame as basic unit for data transmission, each frame is divided into a preamble symbol part and a data part, wherein the preamble symbol part sends a known impulse sequence for channel estimation and synchronization; the data part takes the information to be transmitted; the preamble symbol part is divided into two parts of a positive and negative impulse sequence, which includes odd impulses with alternant positive and negative polarities, and a same direction impulse sequence, which is composed of impulses with same polarity and is the same as the polarity of the last impulse in the positive and negative impulse sequence. The method provides such advantages as high synchronization precision, small storage space, and capability of immediately finding out the synchronization position etc., and provides an important value for the development of the impulse system ultra-wideband wireless communication technique.

Abstract: A method of syncing a serial data stream includes the step of providing a data stream having frames and sub-frames. Each sub-frame is provided with an expected SYNC Word, and there is an expected offset between the SYNC Words in each sub-frame. The data is sent to a plurality of sync modules. Each sync module searches for an expected and different one of the SYNC Words. The sync modules identify an expected SYNC Word, then look for a different one of the SYNC Words at said expected offset from its expected SYNC Word to verify that it has properly identified a SYNC Word.

Abstract: Apparatus, methods, and systems are disclosed, including, for example, a data receiver to receive a calibration voltage and a reference voltage to calibrate the data receiver. The output of the data receiver is provided to a first ripple counter that counts the outputs from the data receiver and provides an output count. The ripple counter may count either ones or zeros. A second ripple counter counts the number of a clock signals over the same period of time. The output count is either multiplied by two or the count of clock signals is divided by two. A ripple comparator may then compare the outputs and adjust the reference voltage based upon the comparison results.

Abstract: Disclosed are various embodiments for circuitry that generates a sync code for wireless transmission. The system generates a sync word according to an identifier of the transmitter, the sync word being unique under a cyclic shift of the sync word. The system inserts a plurality of instances of the sync word into a data stream. The system also transmits, via the transmitter, the data stream to a receiver, the receiver being operable to perform a sliding correlation operation on the sync word.

Abstract: A method of estimating mismatches of a time-to-digital converter (TDC) includes: capturing phase error samples; calculating difference between the phase error samples and an expected value of the phase error samples; and adjusting correction gain of the TDC based on the calculating step. Another method of estimating mismatches of a TDC includes: capturing TDC output code samples; storing a plurality of accumulation values corresponding to different TDC values respectively, wherein each accumulation value records a number of times a TDC value is carried by the TDC output code samples; calculating a desired value based on the accumulation values; calculating difference between the accumulation values and the desired value; and adjusting correction gain of the TDC based on the calculating step.

Abstract: A system and method for calibrating a local radio reference clock for a radio operating in a radio network having a network reference clock. The method comprises determining at the radio an offset between the local clock and the network clock, placing the local clock in a calibration mode, and calibrating the local clock using a radio link to reduce the offset.

Abstract: A communication system includes a communication station that converts a value information into a code value based on a corresponding relationship in which a difference between a first value information and a second value information is set to any value equal to or greater than two, where the second value information corresponds to a code value where an error occurs in one bit of the code value corresponding to the first value information.

Abstract: A control signal receiver includes a converting circuit and a synchronization detection circuit. The converting circuit generates a complex control symbol stream including transmission configurations by converting an input signal. The synchronization detection circuit generates a first bit stream by applying a first determination criterion to the complex control symbol stream and generates a first synchronization signal by comparing the first bit stream with a reference synchronization word. The synchronization detection circuit generates a second bit stream by applying the first determination criterion and a second determination criterion to the complex control symbol stream in that order and generates a second synchronization signal by comparing the second bit stream with the reference synchronization word. The synchronization detection circuit outputs one of the first synchronization signal and the second synchronization signal as asynchronization enable signal.

Abstract: A mobile electronic device that includes a circuitry configured to acquire synchronization with a spreading code of an intermediate frequency signal that is obtained by converting a frequency of a received signal from a satellite in a global positioning system into a predetermined intermediate frequency, demodulate a message included in the intermediate frequency signal, output a primary signal to a predetermined signal line, and attach a predetermined header to a secondary signal and output the result to the predetermined signal line, and includes a display unit configured to display data corresponding to the primary signal and the secondary signal, such that the primary signal includes results of measuring one of position, velocity, and time of the mobile electronic device based on the message that is demodulated by the circuitry, and that the secondary signal includes the intermediate frequency signal.

Abstract: Provided is an equalization device which receives a signal transmitted from a transmission side of the signal as an input signal, and equalizes the deterioration of a wave shape of the received input signal, wherein a bit value indicated by the input signal is judged in accordance with a clock on the basis of the wave shape of the input signal. From judged signals which result from the judgment and which are composed of a plurality of bits, a two-bit transition signal is detected so that the two-bit transition signal has two adjacent bit values having the same value, and bit values located before and after the two adjacent bit values are different from the bit value of the two adjacent bit values, and the phase of the clock is synchronized with the phase of the detected two-bit transition signal.

Abstract: In one embodiment, receiving an Ethernet signal over a channel, the Ethernet signal comprising a preamble frame, an idle frame, and a data frame, the preamble frame comprising one or more preamble codes; synchronizing to the Ethernet signal based on the preamble frame; replicating the one or more preamble codes; and training a decision feedback equalizer (DFE) based on the one or more replicated codes, the training enabling the DFE to use decision values at the DFE output to track channel variations.

Abstract: An Linear Time Code (LTC) receiver for receiving and decoding a LTC frame of the type used in connection with film and television and accompanying audio includes a first counter that measures the number of reference clock periods within the duration of a bi-phase mark signal interval to yield a timing reference for extracting the payload from the LTC frame. A second counter detects a sync field within the LTC frame to establish the LTC frame direction. A third counter serves to count the number of symbols in the LTC frame. A state machine responsive to the counts of the first, second and third counters, serves to (a) detect a valid synchronization sequence within an incoming LTC frame; (b) determine the LTC frame direction, (c) decode (extract) payload information from the LTC frame; and (d) transfer the payload information in an order determined by the LTC frame direction.

Abstract: A correlation calculating method of correlating a received code signal obtained by demodulating a received signal, which is a signal obtained by receiving a positioning satellite signal, with a replica code signal is provided which includes: correlating values of the replica code signal in a chip period with values of the received code signal at first to n-th arrival times obtained by varying an arrival time of the chip period by 1/n chip (where n is an integer equal to or greater than 2); and acquiring a correlation calculation result at a 1/n chip interval by synthesizing the correlation calculation results.

Abstract: Generate a series of digital data according to a pair of differential signals received from a low speed universal serial bus. Calibrate coarsely a frequency of an oscillator according to a width of an end-of-packet of the series of digital data. And calibrate finely the frequency of the oscillator according to a width of a SYNC pattern of the series of digital data.

Abstract: Disclosed are various embodiments for dividing workload in a digital signal processing system. In one embodiment, the system includes at least one analog-to-digital converter configured to receive a three phase analog waveform and a digital waveform. The system can also include a first DSP configured to interface with an external computer and a second DSP configured to receive the digital waveform and isolate a specified frequency range. The system can also include a plurality of DSP's configured to extract specified channels from the specified frequency range and output the extracted channel data.

Abstract: Disclosed herein is a reception apparatus including a calculation section and a storage section. The calculation section calculates correlation values between a data sequence included in a known signal and a received signal at a given point in time. The storage section has at least an area sufficient for storing the correlation values calculated for one frame using the received signal which is one frame long and to which the known signal is added.

Abstract: Embodiments of the invention are generally directed to adjustment of clock signals regenerated from a data stream. An embodiment of a method includes receiving a data stream from a transmitting device via a communication link, the data stream including stream data, a link clock signal, and timestamps to indicate a relationship between the link clock signal and a stream clock signal. The method further includes adjusting the stream clock based at least in part on one or more measurements related to the data stream, the one or more measurements including a count of a number of pulses of the stream clock during a period of time, or a measurement of a number of data elements from the data stream stored in a buffer at a certain point in time.

Abstract: A medical sensor system comprises a gateway comprising a wideband receiver and a narrow band transmitter, the each gateway configured to receive a wideband positioning frame using the wideband receiver from one or more wearable sensors and to transmit acknowledgement frames using the narrow band transmitter that include timing and control data for use by the sensors to establish timing for transmission of the positioning frame; and at least one wearable sensor comprising a wideband transmitter and a narrow band receiver, the sensor configured to transmit a sensor data frame to the gateway using the wideband transmitter and to receive an acknowledgement frame from the gateway using the narrow band receiver, extract timing and control information from the frame, and adjust the timing and synchronization of the wideband transmitter using the timing and control information.

Abstract: Provided is an OFDM receiver which extracts a time sync signal from a prefix having a symmetric structure. The OFDM receiver, according to exemplary embodiments of the present invention, generates the sync signal (e.g., start point) of a symbol by using only the MSB (e.g., sign bit) of the cyclic prefix of an OFDM symbol, reducing the overhead of a logic circuit for generating the sync signal of the symbol.

Abstract: Aspects of the disclosure provide a method for detecting marks. The method includes receiving a data signal from a channel. Further, the method includes matching the data signal to a template that corresponds to a predetermined pattern transmitted over the channel to detect marks, prior to decoding the data signal into a decoded bit stream.

Abstract: A system including a control module and a correlation module. The control module receives signals, including subcarriers having frequencies in a frequency band, via a plurality of antennas, and divides the frequency band into sub-bands each including a plurality of the subcarriers. The correlation module generates sets of correlation values by correlating symbols in the sub-bands with a plurality of preamble sequences. A set of correlation values is generated for one of the plurality of antennas and is generated based on the preamble sequences. The control module generates sums by adding selected correlation values from the sets. The selected correlation values in a sum are generated respectively for the plurality of antennas and are generated based on one of the preamble sequences. The control module detects a preamble sequence in the signals by determining whether a largest one of the sums is greater than or equal to a predetermined threshold.