788 results about "Time error" patented technology

A system, including software components, that efficiently and dynamically analyzes changes to data sources, including application programs, within an integration environment and simultaneously re-codes dynamic adapters between the data sources is disclosed. The system also monitors at least two of said data sources to detect similarities within the data structures of said data sources and generates new dynamic adapters to integrate said at least two of said data sources. The system also provides real time error validation of dynamic adapters as well as performance optimization of newly created dynamic adapters that have been generated under changing environmental conditions.

Disclosed are a transmitting and receiving apparatus and method in an adaptive array antenna system capable of real-time calibration. Transfer functions in the transmitting and receiving apparatus are estimated by injecting a calibration signal to each of transmit and receive channels and analyzing the signals that has passed through the transmit and receive channels. An RF CW sinusoidal signal of a single frequency can be used as the calibration signal to simplify a process of signal processing in a baseband. In addition, in the calibration of the receiving apparatus, gains of all receive channels are controlled using an identical signal. Thus, a relative transfer function characteristic of the receive channels is constant irrespective of the gains of the receivers.

The invention discloses a method for realizing accurate time synchronization by utilizing an IEEE1588 protocol, comprising the following steps: a) a Sync message is transmitted to a slave clock by a master clock, a transmission timestamp TM1 and a receiving timestamp TS1 of the message are acquired by the slave clock; b) a Delay_Req message is transmitted to the master clock by the slave clock, and a transmission timestamp TM2 and a receiving timestamp TS2 of the message are acquired by the slave clock; c) transmission delay and time offset are calculated by the slave clock according to the timestamp; and d) the calculated Offset is corrected in a fixed adjustment frequency in the correction time by the slave clock. The invention realizes accurate time synchronization, calculates time offset and self-compensate through the slave time clock in a packet based network, and leads the slave clock to lock the master clock whether in clock frequency or on the clock time in a shorter time, and occupies little hardware resources.

A network distributed seismic data acquisition system comprises seismic receivers connected to remote acquisition modules, receiver lines, line tap units, base lines, a central recording system and a seismic source event generation unit synchronized to a master clock. One or more high precision clocks is added to the network to correct for timing uncertainty associated with propagation of commands through the network. Seismic receivers and seismic sources are thereby synchronized with greater accuracy than otherwise possible. Timing errors that interfere with the processing of the seismic recordings are greatly reduced, thus enabling an improvement in subsurface geologic imaging.

The invention relates to a method and a system for estimating a symbol time error in a broadband transmission system, comprising: determination a timing error signal of an input-signal of a discrete Fourier-transformation block (5) in a data symbol stream on the basis of intersymbol correlation using a predetermined period in each received symbol, selecting as a predetermined period a number of samples of different useful data parts of a symbol, determining the time error value (ε) based on the intersymbol interference of the selected samples of the different parts of said symbol.

A system and method are provided for determining a position of a Global Positioning System (GPS) receiver prior to bit and frame synchronization. As such, the time-to-first-fix is substantially reduced. More specifically, pseudoranges to five GPS satellites are measured by correlating locally generated Pseudo-Random Number (PRN) codes with signals received from the GPS satellites. After correlation, the pseudorange measurements are correct with an unknown integer number of milliseconds error, which is different for each of the pseudorange measurements. Using the measurements of the pseudoranges and a mathematical model where each of the pseudorange measurements is forced to have a common channel time error, the user position and the common channel time error are determined prior to bit and frame synchronization.

The invention discloses a drive control unit, a drive circuit and a drive control method of a display substrate. The drive control unit comprises a time schedule controller and a delay controller, wherein time schedule controller sends sequential control signals to the delay controller, the delay controller is used for regulating the sequential control signals according to impedance of a drive signal wire connected with pixel points of the display substrate, and real charge duration of the pixel points is within a preset duration range. According to the drive control unit, the drive circuit and the drive control method, the sequential control signals of the pixel points are changed according to positions of the pixel points on a liquid crystal panel, the sequential control signals of pixel points in different positions are different, charge time errors caused by signal wire delay are compensated by the different sequential control signals, and consistency of charge effects of the pixel points in the different positions of the liquid crystal panel is guaranteed.

A timing error compensation system in an OFMD/CDMA communication system includes an analog-to-digital converter for converting an OFDM signal, comprised of a data symbol stream in which a pilot symbol is inserted at intervals of a prescribed number of data symbols, received from a transmitter, to a digital OFDM symbol stream by prescribed sampling synchronization, a guard interval remover for removing a guard interval inserted in the OFDM symbol by prescribed frame synchronization, and a fast Fourier transform (FFT) device for performing fast Fourier transform on the guard interval-removed OFDM symbol and outputting a data symbol stream. In the time error compensation system, a pilot symbol detector receives the data symbol stream and detects the pilot symbols inserted in the data symbol stream at prescribed intervals. A timing compensator determines a linear phase difference line for the detected pilot symbol, generates a timing error estimation signal according to the determined linear phase difference line, and provides the timing error estimation signal to the analog-to-digital converter and the guard interval remover so as to determine the sampling synchronization and the frame synchronization.

The invention is a digital lathe error real-time compensator based on lathe external coordinate system offset. It includes calculating and processing module, CNC port and motion control module, sensor and transmitting module. The sensor and transmitting module is linked with calculating and processing module by data cables. The calculating and processing module is linked with CNC port and motion control module by data cables and communication protocol and acquires the input and output, saving, calculating of the signals. The CNC port and motion control module offsets the lathe external coordinate system to extra move the lathe by service system according to compensating value received as signals outputted from the calculating and processing module. The sensor and transmitting module gathers the temperature and heat error signals of the lathe and transmits to processing module after processed. The calculating and processing module may links with the computer so to acquire the command and data transferring and saving between the superior and inferior machine. The invention is of simple structure, handily use, low cost, highly real-time, more efficient compensation with a bright industrializing foreground.

The invention discloses a self-adoptive correcting device of mismatch error of time-interleaved analog-digital converter, comprising an M channel TIADC, a signal recombination, a digital reference signal memorizer, a simulated reference signal generator, a self-adaptive reconstruction filter bank, a clock generation circuit and a subtraction device. Signals after passages are reconstructed are used to correct each passage instead of single correction on each passage, thereby solving the problem that when an input signal bandwidth is larger than the Nyquist frequency of each passage ADC, the time error can not be corrected due to aliasing. Each self-adoptive reconstruction filter is divided into a plurality of sub-filters for concurrent working, thereby not improving the requirement of thetreatment speed for a self-adoptive correcting filter while realizing the effect of signal recombination and ensuring the practicability of the hardware of the structure of the invention. A digital reference signal is internally installed in the device and is taken as a target to carry out the self-adoptive correction, pre-measuring or calculating a passage mismatch error is not needed, and the source of the error is not needed to be discriminated so that various mismatch errors can be corrected.

The invention discloses an audio synchronization output method and a system. The system comprises a control terminal, a media server and a plurality of play terminals which are accessed to a local area network. The method comprises the steps that S1, the control terminal selects one play terminal from the local area network to serve as a reference terminal, and sends a synchronization instruction to the reference terminal; S2, the reference terminal downloads specified audio information from the media server, decodes the audio information for generating digital audio information, and sends a clock synchronization coordination instruction to the specified play terminals, and the clock synchronization coordination instruction enables the play terminals to send clock synchronization coordination instruction return values to the reference terminal, and synchronizes a clock to the reference time; and S3, the reference terminal sends the digital audio information to the play terminals feeding back the clock synchronization coordination instruction return values within the required time for synchronously playing the digital audio information on the play terminals. Play time errors among the play terminals are reduced, and the quality of an audio is guaranteed.

The invention discloses a system and method for testing satellite-ground time delay and onboard time errors. The method comprises the steps of: firstly, acquiring format pulses generated based on onboard telemetering, and recording GPS (Global Position System) time generated by the format pulses; and then, demodulating to generate telemetering format pulses by using a special testing device and recording the GPS time for demodulating the format pulses. The satellite-ground time delay can be calculated by means of two telemetering format pulses read by an oscilloscope, and can also be acquired by calculating a difference between two GPS time through a program. A 1553B bus monitoring module is used for monitoring air time codes of a center computer of a satellite on a bus, a GPS data receiving processing module is used for acquiring ground GPS time, and a master control module is used for calculating difference values between the air time codes and the ground GPS time so as to acquire the onboard time errors. The satellite-ground time delay measurement precision is not less than 200us, and the onboard time measurement precision is not less than 100us.

A hold time error list, having for each hold time error path a hold time error value satisfying plural timing constraints, and more specifically a maximum hold time error value for each of timing constraints, as well as a setup time margin map allocating to path a setup time margin satisfying plural timing constraints for each setup time error path, and more specifically minimum value of setup time margins for the same path for each timing constraint, are generated. Also, referring to this setup time margin map, delay buffers, which reduces or eliminates hold time error of hold error list, and a delay of which is within the range of delay amounts and positions equal to or lower than the setup time margin, are inserted. Referring to the setup time margin map, it is possible to insert delay buffer to correct hold time error without causing new setup time errors.

Provided is a system and method for detecting a power system condition of a power system. The system includes at least a first and second intelligent electronic device (IED) operatively coupled to the power system at respective first and second power system locations. Each IED is configured to calculate a measured time value based on a frequency dependant parameter such as a secondary voltage signal at their respective locations, to compare the measured time value to a reference time value to form a time error, and to transmit the time error. The system further includes a third IED configured to compare respective time errors received from the first and second IEDs to form a time differential error, to map the time differential error back to their power system locations, and compare the time differential error to a predetermined threshold to determine the power system condition.

A method and apparatus for improving the accuracy of a round trip time (RTT) estimate between a first device and a second device are disclosed. The method involves calculating an acknowledgement correction factor and a unicast correction factor. These correction factors are used to compensate for symbol boundary time errors resulting from multipath effects.

The invention discloses a direct-current power distribution network protection method based on voltage characteristic traveling wave similarity measurement. According to the method, the transient voltage currents at the two ends of a line after a direct-current fault occurs are subjected to high-frequency sampling, and are converted into line mode voltage forward traveling wave of one side of a protection area and line mode voltage inversion traveling wave of the opposite side; and based on traveling wave refraction reflection and polarity difference of intra-region and extra-region faults offorward inversion traveling wave at the two ends caused by mismatching of impedance of fault points, the similarity between the two waveforms is reflected by utilizing a globally optimal neighborhooddiffusion compatible dynamic matching similarity measure algorithm, so that the intra-region and extra-region faults can be reliably identified. According to the method, the traveling wave transmission delay and the time-to-time error can be compensated, influence from the sampling frequency deviation at the two ends, data missing and damage and the like is not caused easily, the fault tolerance is relatively high, the detection speed is high, and the power supply operation of the direct-current power distribution network is more reliable.

The invention relates to a multi-sensor combined navigation time synchronizing system based on a field programmable gate array (FPGA). The multi-sensor combined navigation time synchronizing system comprises a global navigation satellite system (GNSS) receiver, a navigation sensor group, an FPGA module and a combined navigation computer, wherein the GNSS receiver and the navigation sensor group are connected with the FPGA module respectively; the GNSS receiver and the FPGA module are connected with the combined navigation computer respectively; the FPGA module is used for decoding output data of the GNSS receiver to obtain receiver time, adding the receiver time, as a time tag, into measurement data of the navigation sensor group, and performing coding to obtain synchronous measurement data; the combined navigation computer is used for processing the received synchronous measurement data and the output data of the GNSS receiver, and outputting a final navigation positioning result. Compared with the prior art, the multi-sensor combined navigation time synchronizing system has the advantages that time errors of measurement data of navigation sensors can be effectively eliminated, and high-accuracy combined navigation in a high-speed environment is realized.

The invention discloses a method and a system for protecting time transfer in synchronization network; a corresponding module is added to the prior art to use time synchronization frequency of the synchronization network as the basis of time synchronization protocol, so the network is ensured to synchronously lock clock signal; a synchronization network clock source which participates in selection is configured, and the clock source selection mode is configured; current clock source is selected according to the selection mode, and the frequency state of the current clock source is synchronously locked; the current clock source state is used as state basis of accurate time protocol port to sequentially lock time of element location nodes in the synchronization network. The corresponding module is added to the prior art to use time synchronization frequency of the synchronization network as the basis of time synchronization protocol, so the time transfer error in element location nodes is greatly reduced, and the time error in large scale networking is reduced, and the stability of synchronization network is improved in the switching process of clock sources.

The invention discloses a cell switching method and device. The cell switching method and device is used in a satellite communication system and enables switching of a user to be low in synchronization time error and high in success rate. Meanwhile, according to the cell switching method and device, in a switching process, excessive occupancy of resources is avoided, and the using rate of the resources is improved. The cell switching method comprises the following steps: network-side equipment sends a synchronization parameter of a target spot beam to user equipment (UE) to instruct the UE to stay synchronous with the target spot beam, the network-side equipment then acquires position information of the UE and power information of the spot beam, and then the network-side equipment judges whether to carry out cell switching on the UE or not according to the position information of the UE and the power information of the spot beam, wherein the position information of the UE and the power information of the spot beam are reported by the UE.

The invention discloses a range migration correction method for a pulse Doppler (PD) radar in a feeble signal detection process, which mainly solves the problems that the discrete time sampling error is not considered, and the detection performance is low in the prior art, and is realized by the steps as follows: transmitting a set of linear frequency-modulation pulse signals of which the bandwidth does not exceed 1 percent of a centre carrier frequency by the radar; carrying out mixing on echo data to obtain a base band radar echo signal; carrying out Fourier transformation on the base band radar echo signal in a fast time domain; carrying out digital pulse compression on a signal obtained by carrying out the Fourier transformation through the fast time domain in the fast time domain, and finding out a corresponding pulse signal when the discrete time error is minimum; by taking the pulse signal as an alignment reference, realizing Keystone transformation by using an SINC interpolation method, and carrying out Doppler fuzzy compensation; and carrying out the Fourier transformation in the fast time domain, and carrying out coherent accumulation to work out a range cell in which the target is located and a Doppler channel. Compared with similar methods, the range migration correction method for PD radar in the feeble signal detection process is capable of reducing the influenceof the discrete time sampling error to minimum, and is capable of improving the detection performance of a radar system.

When insufficient traffic is present in the network to maintain synchronization in this manner, other methods must be used. One approach involves making direct measurements of the timing between base stations. This is accomplished in one of two ways. The base may interrupt its transmissions on all sectors for a short interval during which it determines the time of arrival of signals from other base stations. Given knowledge of the other base station locations, time errors relative to all other base stations may be derived. Alternatively, the base may send a short signal at high power in the mobile transmit band. This time-of-arrival of this signal is measured by the surrounding base stations and the time errors between pairs of base stations are computed. In some cases, a base station may be isolated sufficiently from all other base stations in the network such that direct base-to-base measurement is not viable. In this case, a fixed mobile is placed at a location in the handoff region between the isolated cell and another cell in the network. The fixed mobile either performs measurements of base station pilots on command of the base and reports the timing information, or sends a burst transmission at a specified time and power level to be measured by the base stations.