261results about "Data rate detection arrangements" patented technology

An apparatus for measuring a roundtrip delay time associated with communication of multimedia data is provided. In one embodiment, the apparatus comprises a video encoder for encoding multimedia data to produce encoded multimedia data; a transmission rate controller for controlling transmission rate of the encoded multimedia data according to an effective transmission rate; and a first sending / receiving unit for sending the multimedia data via a first channel.

Processing of loop-back information returned by one or more mobile stations that are served by a wireless communication network permits the network to compensate its transmit signals for increased transmission efficiency and reduced signal interference at the mobile stations. Generally, the network forms one or more transmit signals as a combination of different signals intended for the different mobile stations, and remembers transmit information associated with these transmit signals. The mobile stations return loop-back signals to the network, which determines transmit signal compensation information by comparing loop-back information to memorized information. The mobile stations may loop-back samples from composite received signals, from processed received signal samples, or loop-back estimates. In the first case, processing at the network involves compensating the combined transmit signals at the transmit modulation rate, while the second case involves symbol rate processing of the individual information streams intended for the different mobile stations.

The system in one embodiment relates to tightly integrating parameter estimation, symbol hypothesis testing, decoding, and rate identification. The present invention provides Turbo-decoding for joint signal demodulation based on an iterative decoding solution that exploits error correction codes. The system iteratively couples an initial amplitude estimator, a symbol estimator, a bank of decoders, and a joint amplitude estimator to produce the symbol estimates.

The present invention provides an improved receiver for data-rate detection in a signal received from a transmitter of a cellular radio communication system including multiple transport channels supporting variable data-rate transmissions. This is accomplished by a computationally efficient technique for data-rate detection. The improved receiver receives data and TFCI associated with each of the multiple transport channels. The receiver then obtains a maximum number of valid transport format combinations and a maximum number of TFCIs that can be formed. The receiver then computes a subset of TFCIs using the obtained maximum number of valid transport format combinations and the maximum number of TFCIs, and decodes from the computed subset of TFCIs within the frame to reduce computation during decoding and to improve data-rate detection reliability.

Methods and apparatuses consistent with the present invention recover a clock signal from a variable bit rate data signal by estimating, in the time domain, the bit rate of the data signal, and based on the estimated variable bit rate, determining a center frequency of a narrow-band filter for extracting the clock signal from the data signal. A clock recovery circuit consistent with the present invention extracts a clock signal from a variable bit rate data signal by estimating a minimum time interval between transitions in the data signal, generating a plurality of pulses that correspond respectively to transitions in the data signal, adjusting the duration of each of the pulses based on the estimated minimum time interval and inputting into a narrow-band filter the adjusted pulses, determining a center frequency of the narrow-band filter based on the estimated minimum time interval, and extracting in the narrow-band filter the clock signal from the adjusted pulses.

A microprocessor controlled data recovery unit with an adjustable sampling and signal comparison level. The data recovery unit includes a data channel and a monitor channel. The monitor channel samples an incoming data stream in a varying manner. The results of the sampling in the monitor channel are used to adjust the sampling and comparing of the signal in the data channel. The data recovery unit includes a PLL based clock recovery unit in one embodiment, and in another embodiment the clock signal is derived by the microprocessor.

An apparatus for measuring a roundtrip delay time associated with communication of multimedia data is provided. In one embodiment, the apparatus comprises a video encoder for encoding multimedia data to produce encoded multimedia data; a transmission rate controller for controlling transmission rate of the encoded multimedia data according to an effective transmission rate; and a first sending / receiving unit for sending the multimedia data via a first channel.

A communication system transmits orthogonally encoded data at a symbol rate which is selected from a plurality of symbol rates. The data is encoded in a plurality of packets, each packet having a plurality of symbols having signal points in a field. The signal points of consecutively transmitted symbols are correlated unless the rate is changed, and the data is encoded such that only particular orthogonal descendants of a selected maximum rate code are used. The encoded data is transmitted to a receiver, and orthogonally decoded. A change in the rate of data transmission is recognized when the signal points of consecutively transmitted symbols are not correlated.

A communication terminal includes a first wireless communication unit that communicates with a base station; a second wireless communication unit that communicates with another communication terminal including an equivalent of the first wireless communication unit; a temperature measurement unit; and a control unit that selects one of the first wireless communication unit and the second wireless communication unit according to a temperature measured by the a temperature measurement unit.

To detect the Synch Field accurately and find the beginning of a frame in order to calculate the baud rate. A slave device is connected to a bus and receives a binary level signal on the bus transmitted from a master device. The slave device detects the signal level of the binary level signal and calculates the time of a first period and a second period when the binary level signal is at a low level, which respectively exist before and after the binary level signal is at a high level. When the ratio of the first period to the second period is not less than 11, the binary level signal that the device continues to receive after the second period is identified as the Synch Field. From the reciprocal number of the second period, the baud rate for the slave device to receive the binary level signal is calculated.

A communications device includes: an IrDA frame detecting section 202, an IrSimple frame detecting section 201, and a transfer rate control section 230. The IrDA frame detecting section 202 detects a first predetermined frame based on pulses detected in an incoming response signal at first predetermined intervals. The IrSimple frame detecting section 201 detects a second predetermined frame based on pulses detected in the incoming response signal at second predetermined intervals. The transfer rate control section 230 determines that the transfer rate of the response is equal to the first transfer rate if the IrDA frame detecting section 202 detects the first predetermined frame and determines that the transfer rate of the response is equal to the second transfer rate if the IrSimple frame detecting section 201 detects the second predetermined frame.

An integrated circuit arranged and constructed to determine an upper data rate for a variable data rate signal and method thereof includes a buffer, comparator, and combiner that are operable to compare a characteristic, such as an energy statistic of a number of partial symbols constructed from the variable data rate signal to a first threshold that corresponds to the number to provide a first comparison; process the variable data rate signal at a first data rate when the first comparison is favorable; compare the characteristic to a second threshold that corresponds to the number to provide a second comparison; and combine the partial symbols to provide other partial symbols at a second data rate that is less than the first data rate when the second comparison is favorable.

A clock recovery system (10) for recovering an input data signal (14) clock. A rate detector (20) detects the input data signal bit rate and provides range signals (30a-c) specifying progressive ranges encompassing the bit rate. A frequency detector (22) provides a frequency error signal (32) based on frequency difference between the input data signal and a recovered clock signal (16). A phase detector (24) provides a phase error signal (34) based on the input data and recovered clock signals. A filter-controller (26) provides an oscillator driving signal (36) based on the range, frequency error, and phase error signals. An oscillator-divider (28) then provides the recovered clock signal based on the oscillator driving signal and at least some of the range signals. The phase detector, filter-controller, and oscillator-divider collectively thus form a phase locked loop. Optionally, the clock recovery system (10) may also provide a recovered data signal (18).

A method and system for transmitting at least one client signal within a server signal which has a predetermined transmission bit rate, with the transmission bit rate of the client signal and the transmission bit rate of the server signal being different. To this end, at least one identification number, which indicates the transmission bit rate relationships, is determined for at least one client signal at the transmission end, and the data in the at least one client signal are inserted uniformly into the server signal via sigma-delta modulation and using the determined identification number. The server signal is transmitted with the determined identification number and, at the receiving end, the data in the at least one client signal is determined via sigma-delta modulation and using the transmitted identification number.

An asynchronous receiver / transmitter provides autobauding with adjustment to a programmable baud rate. A baud divisor is calculated based on a detected size of a start bit. The asynchronous receiver / transmitter provides a plurality of baud divisor replacement registers, each register storing a baud divisor threshold and a baud divisor replacement. The baud divisor is compared to the plurality of programmed baud divisor thresholds. Based on the performed hardware comparison, the baud divisor is automatically replaced by a baud divisor replacement for a particular baud divisor range defined by a baud divisor threshold and including the baud divisor. The baud rate corresponding to this baud divisor replacement represents the appropriate baud rate. Autobauding with adjustment to a programmed baud rate corrects for measurement inaccuracies with respect to the start bit size. Autobauding with adjustment to a programmed baud rate also permits an asynchronous receiver / transmitter to reliably support high speed baud rates. Further, the programmable nature of the baud divisor thresholds and baud divisor replacements permits an asynchronous receiver / transmitter to support autubauding at multiple asynchronous receiver / transmitter frequencies.

System and method for analyzing communication signals. A digital signal comprising multiple samples is received, representing a plurality of binary symbols. Zero crossings of the signal are determined, each comprising a respective first sample immediately preceding the zero crossing and a respective second sample immediately following the zero crossing. Per zero crossing, an error expression is determined interpolating between the first and second samples as a function of estimated period T and estimated offset tau of the signal. Based on the error expressions, values of T and tau are determined using a linear fit that minimizes a total error of values of the error expressions. T and tau are usable in analyzing the signal, e.g., each zero crossing corresponds to a respective symbol represented by a respective segment of the signal. The segments are overlaid based on T and tau, forming an eye diagram usable to analyze the signal.

The invention provides a multi-gear code rate adaptive demodulation system and method based on a neural network so as to solve the technical problems of high complexity of realization of an existing multi-gear code rate adaptive demodulation system and large computation amount of a demodulation method. In the demodulation system, an ADC sampling module samples an analog modulation signal; a code element feature point extraction module carries out detection on phase jump points of the sampled signal by utilizing a one-dimensional convolution neural network trained by a neural network construction module; a code rate estimation module estimates code rate of the sampled signal according to the detection result; a signal-to-noise ratio estimation module estimates signal-to-noise ratio of the sampled signal; a controller module selects low-pass filter coefficients and an interpolation structure of a demodulation module according to the code rate estimation result and the signal-to-noise ratio estimation result, and calculates sampling rate conversion ratio of the demodulation module; and finally, the demodulation module carries out demodulation on the sampled signal according to the selected low-pass filter coefficients and the interpolation structure as well as the calculated sampling rate conversion ratio.

Systems and methods for synchronizing a source and sink device are disclosed. A sink device can efficiently determine the source data rate even in cases where the sink device is not directly coupled to the source device. A method for transmitting a source data stream from a source device to a sink device includes, forming a logical channel from a source device to a sink device, where the logical channel is configured to carry the source data stream, and one or more rate parameters. The rate parameters relate a data rate of the source data stream to a data rate of the logical channel. A method for a sink device to recover a source data rate includes, detecting a logical channel in a received data stream where the logical channel includes the source data stream, recovering one or more rate parameters from the received data stream, determining a data rate of the logical channel, and determining the data rate of the source data stream based on the data rate of the logical channel and the one or more rate parameters. Corresponding systems and computer program products are also described.

Acquisition of a waveform such as a continuous-phase modulation (CPM) waveform is described. In one embodiment of the invention, the invention is directed to a method and apparatus for acquiring a waveform as defined by MIL-STD-188-181B including the preamble of such a waveform at a performance level defined by the standard. The present invention provides solutions to at least four primary issues presented in acquiring a CPM waveform such as the MIL-STD-188-181B compliant waveform. These primary problems include searching for the preamble, determination of the symbol rate, determination of an initial carrier frequency error (Doppler), determination of an initial carrier phase, and determination of the start-of-message to establish an absolute time marker within the waveform.

A computer implemented method for determining frequency and slope of a linear frequency modulated signal. Windowed signal data is collected and used for formulating a search surface function which can be calculated recursively. The function is divided into parts. Part values are calculated at an underspecified number of points corresponding to the number of parts. The search surface function part values are interpolated at values between frequency values. An interpolation geometry is chosen and then the function part values are interpolated at values between frequency values and slopes. Function parts are added together giving a restored search surface function. The frequency and slope values can be searched to find the values that maximize the search surface function. Other embodiments result in faster execution.

A method and apparatus for determining the appropriate timing interval for each bit or data symbol in serial data communications. A sending device transmits a predetermined bit sequence, such as a binary pattern corresponding to one byte, either on its own initiative or in response to an action of a receiving device. A microprocessor in the receiving device measures a calibration time interval between the leading edge of a start bit and a subsequent marker transition, either between subsequent data bits or between the final data bit and the stop bit. This measured interval may be mathematically converted to units useful to calibrate a function or device that conducts input / output operations. Optionally, the process may be repeated periodically to compensate for clock rate drift. This invention may be used for autobaud data rate detection, or matching the actual data rate of a remote serial device, and permits accurate communications without precision timing references.

A method of dynamically- and continuously-variable rate asynchronous data transfer, such as for use in an electronic blasting system, may employ a device that transmits data including synchronization bits and bits conveying other information, and a device that ascertains the rate of transmission of the synchronization bits and receives the bits conveying the other information at the ascertained rate of transmission.

A system can be configured to control an equalizer circuit to equalize a data signal without requiring prior knowledge of the data signal's data rate. In an example, the system includes an equalizer circuit configured to equalize a data signal based on an equalizer control signal to produce an equalized signal, and a pattern detector configured to detect a specified data pattern in the equalized signal at each of multiple sampling rates. A control circuit can be configured to generate a preferred equalization control signal based on a sampling rate, selected from the multiple sampling rates, at which the pattern detector detects the specified data pattern in the equalized signal.

Methods and apparatus are provided for automatic rate identification and channel synchronization in a master-slave setting for high data throughput applications. An interface is provided for use between a parallel bus and a serial bus. The interface includes a plurality of serializer / deserializer circuits that generate a clock signal, wherein one of the serializer / deserializer circuits is a master circuit generating a master clock signal and the remaining of the serializer / deserializer circuits are slave circuits generating slave clock signals. The master clock signal is substantially phase-aligned to a reference clock and is distributed to the slave circuits. The interface also includes a clock divider associated with the master circuit for selectively generating a master clock signal having one or more lower data rates than the reference clock; and a frequency detector associated with each of the slave circuits for automatically detecting a rate of the master clock signal.

A wireless communication terminal comprises: a packet receiving unit for receiving a packet from a wireless base station; module for obtaining a transmission rate and a required transmission time from the received packet; module for calculating a time required to perform a packet transmission / reception procedure on the basis of the required transmission time; an analysis unit that functions as module for recognizing the existence of other terminal by decoding a destination MAC address described in the packet when the obtained transmission rate is equal to or lower than a transmission rate used by the wireless communication terminal; and a same-cell terminal list creation unit and band use time period scheduling unit for setting a band use time period that is equal to or greater than the time required to perform the packet transmission / reception procedure, for a time period, within a predetermined period corresponding to a packet generation period, regarding the other terminal and the wireless communication terminal, in order from the terminal having the lowest transmission rate.

In an auto baud system and method, the baud rates between two communicating devices are synchronized by timing the transmission of a plurality of bits by counting the cycles of a reference clock. The number of cycles counted is then divided by the number of bits counted over and any remaining cycles are distributed evenly across the data being transmitted or received. The interface of the circuit is preferably implemented as a single pin, open drain interface which can be connected to an RS-232 communications link using external hardware.

A data transmission method etc. are provided. At the transmitting side, an error-detecting code of the transmitted data is calculated, frame by frame, the error-detecting code is arranged after the corresponding transmitted data, and frame data is generated in such a way that bit arrangements of the transmitted data and of the error-detecting code are set in a reverse order to each other. At the receiving side, the transmitted data and the error-detecting code are assumed by assuming a final bit position of the frame data, frame by frame, for the received frame data and the error-detecting code of the assumed transmitted data is calculated. A position such where the assumed error-detecting code agrees with an error-detecting code calculated on the basis of the assumed transmitted data is determined to be the final bit position of the frame data.

A method for demodulating an ultra-wide band (UWB) signal includes detecting a detecting a data rate of the UWB signal, selecting one from plurality of clock signals in response to the detected data rate, decoding the UWB signal in accordance with the selected clock signal, and outputting transmission data determined by a fast clock. The plurality of clock signals includes at least one frequency different from other frequencies. A receiver for an UWB signal includes an OFDM demodulating unit demodulating the UWB signal into an OFDM symbol, and a bit-level processing unit demodulating the OFDM symbol into bit-level data. The bit-level processing unit receives a scaled clock signal having a frequency corresponding to one of a plurality of data rates of the UWB signal. The method and apparatus may reduce static power consumption and improve performance of the receiver.

In a wireless 802.15.4 communication system, a method and system are provided for switching between a predetermined protocol transmission mode and a high-speed transmission mode by including signaling mode information in a data packet (330, 340) to instruct the receiver device (300) to demodulate at least a data payload using the predetermined transmission mode if the signaling mode information comprises a first predetermined value, and to demodulate at least the data payload using the high-speed transmission mode if the signaling mode information comprises a second predetermined value. The signaling mode information may be included in the SFD field of an 802.15.4 SHR structure to instruct the receiver how to demodulate or process the data packet, or may be included as desired anywhere in the data packet to instruct the receiver how to demodulate or process one or more subsequent data packets.

The speed of asynchronous serial communications is detected by determining a duration of a data bit within an asynchronous data stream. The duration of the data bit is used to generate a clock frequency. The clock frequency is used to clock data from the asynchronous data stream into a register. The clocked data is processed according to an error indication.