A synchronization detection method executed by a processor included in a transmission apparatus, the synchronization detection method includes receiving a frame in accordance with a predetermined timing; calculating an unmatched bit number that indicates a number of unmatched bits between a bit stream of the received frame and an expected bit stream that indicates a bit stream that has been expected to be received; acquiring an accumulated number by accumulating the unmatched bit number at the predetermined timing; determining whether the received frame is synchronized with a predetermined signal by comparing the accumulated number and a predetermined threshold; and starting processing for establishing synchronization between the received frame and the predetermined signal when it is determined that the received frame is not synchronized with the predetermined signal.

A connection status detector of a controller determines that a two-wire cable is forward connected, in a case where a synchronization pattern of reception data completely coincides with a synchronization pattern for forward connection check. The connection status detector determines that the two-wire cable is reversely connected, in a case where the synchronization pattern of reception data completely coincides with a synchronization pattern for reverse connection check. A transmission data inverter reverses an uplink signal output from a transmission data processor, in a case where it is determined that the two-wire cable is reversely connected. A reception data inverter reverses a downlink signal output from a reception driver, in a case where it is determined that the two-wire cable is reversely connected.

This application provides a synchronization signal transmission method and a communications apparatus. The synchronization signal transmission method and the communications apparatus are applied to the communications field. In the synchronization signal transmission method, a synchronization signal generated and sent by a network device may include a first sequence and a second sequence. The first sequence is a first complex sequence or a sequence obtained based on the first complex sequence. The second sequence is a sequence obtained based on the first complex sequence, and the second sequence is different from the first sequence. Because a correlation processing result between the first sequence and the second sequence is still a complex sequence, there is a good correlation property, so that a terminal device can obtain a relatively sharp correlation peak when synchronizing with the network device based on the synchronization signal, thereby effectively shortening duration required for synchronization.

A system and a method for time synchronization on a wireless network, based on the exchange of Chirp Spread Spectrum information. Time signals are broadcast from a master (40) to a plurality of slave devices (101, 102, 103). The modulation used includes a compensation of offsets in the master's system clock by symbol-wide frequency shifts that is particularly precise, fine and simple to implement. The system and method of the invention are particularly suitable for synchronizing a telecommunication cell network.

A method for transmitting useful information between a transmitting terminal and a receiving terminal connected via a transmission channel. The transmitting terminal defines control information for the useful information, and searches in an association table, which is accessible from the transmitting terminal, for a frame-synchronization word associated with the control information. The transmitting terminal generates a frame of data from the useful information, and transmits, over the transmission channel, a data stream that includes the frame-synchronization word and the frame of data.

The invention relates to the technical field of vehicle-mounted Ethernet communication, in particular to a detection system for a vehicle-mounted Ethernet link synchronizing signal, which comprises a signal characteristic judgment module, the signal characteristic judgment module generates a synchronization mode identifier according to the signal characteristic of the synchronizing signal; a rate judgment module, the rate judgment module generates a working rate identifier according to the synchronizing signal; and a synchronization module, the synchronization module is respectively connected with the signal characteristic judgment module and the rate judgment module, and the synchronization module generates synchronization information for handshake between the vehicle-mounted Ethernet device and the external device according to the synchronization mode identifier and the working rate identifier and outputs the synchronization information.

The invention relates to the technical field of vehicle-mounted Ethernet communication, in particular to a detection system for a vehicle-mounted Ethernet link synchronizing signal, which comprises a signal characteristic judgment module, the signal characteristic judgment module generates a synchronization mode identifier according to the signal characteristic of the synchronizing signal; a rate judgment module, the rate judgment module generates a working rate identifier according to the synchronizing signal; and a synchronization module, the synchronization module is respectively connected with the signal characteristic judgment module and the rate judgment module, and the synchronization module generates synchronization information for handshake between the vehicle-mounted Ethernet device and the external device according to the synchronization mode identifier and the working rate identifier and outputs the synchronization information.

A physical layer (PHY) device, for use in an Ethernet network, includes a cable interface, a transmitter, a receiver and a processor. The cable interface connects to an Ethernet link for communicating with a peer PHY device. The transmitter transmits outbound signals that carry outbound data to the peer PHY device over the Ethernet link. The receiver receives inbound signals that carry inbound data from the peer PHY device over the Ethernet link. The processor (i) controls the transmitter to transmit, to the peer PHY device, an outbound pre-alert signal indicating that the PHY device is about to start transmitting the outbound signals, and (ii) in response to receiving, via the receiver, an inbound pre-alert signal from the peer PHY device during a period in which the peer PHY device is abstaining from transmitting the inbound signals, controls the transmitter to abstain from transmitting the outbound signals.

Provided are a method for determining and sending a multiframe, and a communication device. The method includes: for physical layers of different interface bandwidth speeds, determining a multiframe number of the multiframe to be n-th power of 2, where n is a minimum positive integer that causes the multiframe number greater than or equal to a number of timeslots of a physical layer, identifier values of the multiframe identifier for identifying the multiframe number are sequentially carried in preset positions of overhead blocks of respective frames constituting the multiframe, and the number of the identifier values of the multiframe identifier is the same as the multiframe number. The identifier values of the multiframe identifier are a preset number of consecutive 0s and the preset number of consecutive 1s in sequence.