52results about How to "Sync frequency" patented technology

The invention discloses a device and a method for synchronizing system frequency in a packet transport network, and relates to a packet transport network in optical communication. The system frequency synchronizing device comprises a microcomputer processor, a field programmable gate array (FPGA) processing module, a clock integrated circuit, a packet transport network service disk, a synchronous state byte extracting module, a synchronous state byte generating module, a phase locked loop circuit, an external clock input circuit, a high stable crystal oscillator, a clock distributing circuit, a HDB3 coding module and an external clock output circuit, wherein the FPGA processing module comprises a preceding stage preselector, a priority level control module, a first selector, a second selector and a third selector. By the device and method, the system frequency in the whole packet transport network can be synchronized rapidly, data business package transmission and smooth transition can be carried out rapidly and hierarchically, and the device is flexible and has high reliability.

Weighted addition in point to point between data at back Ng points in OFDM original data and training sequence at transmitting end of OFDM system constitutes guard gap. OFDM original data is unchanged. Fusion algorithm is utilized in the receiving end of OFDM system. Correlativity between data in guard gap and data at back Ng points in OFDM original data as well as correlativity induced by the training sequence are utilized synthetically to process the received data for realizing time and frequency synchronism. The invention makes OFDM system possess good synchronous performance as well as has advantages of small interference on data caused by training sequence.

The invention provides a synchronization method and apparatus. The method comprises the following steps: first UE maps data to be transmitted and a first sequence onto symbols in a first time unit toobtain a first signal. The first sequence is mapped onto at least one symbol of a non-starting location in the first time unit, and the first UE sends the first signal to second UE. The second UE receives the first signal, obtains a first sequence, and synchronizes the first signal according to the first sequence. By transmitting the first sequence for synchronization on the symbols of the non-starting portion of each data transmission, when the CP length of the symbol for sending the data cannot meet the time synchronization requirement, a receiving end device can still use the first sequenceto perform time synchronization on the currently received data, and meanwhile use a CP structure to perform frequency offset estimation to achieve frequency synchronization.

The invention provides a punching device for a strip-shaped material strip. Through the punching device, it can be guaranteed that a punching arm of a punching machine and a stepping motor of a feeding clamping mechanism are synchronous in frequency. The punching device comprises the punching arm and a punching die set connected with the lower portion of the punching arm. The die set is provided with a die pressing area. The die pressing area is connected with a feeding device in the feeding direction. The feeding device comprises a feeding track and feeding clamping mechanisms. The feeding clamping mechanisms are arranged on the two sides of the feeding track and driven through the stepping motor. The punching arm is fixedly connected with a synchronous drive arm. The stepping motor is provided with a rocker type switch. The rocker suspension end of the rocker type switch is located in the stroke of the synchronous drive arm. According to the punching device, it can be guaranteed that the punching arm and the stepping motor of the feeding clamping mechanisms are synchronous in frequency, accordingly the error of the feeding distance in the punching process is reduced, the precision of the feeding distance is guaranteed, and material waste is avoided.

The invention relates to a wireless signal transmit-receive apparatus, comprising an antenna, a low noise amplifier, a mixer, a frequency generator, an amplitude limit amplifier, a modulator and a photoelectric converter. The antenna is used for receiving a pulse signal. The low noise amplifier is used for conducting low noise amplification on the pulse signal received by the antenna, and generating processing pulse signal and sending to the mixer. The frequency generator is used for generating a frequency signal and sending it to the mixer. The mixer processes the frequency signal into communication electric signal based on the processing pulse signal. The amplitude limit amplifier is used for conducting amplitude limit amplification on the communication electric signal, and generating amplification electric signal. The modulator is used for conducting protocol transition on the amplification electric signal and generating electric signal. The photoelectric converter is used for converting the electric signal to the optical signal, and sending the optical signal to an optical receiver. The invention is advantageous in that millimeter wave communication technology and optical communication technology are combined, and the special-purpose communication protocol is adopted to achieve vehicle-earth large-capacity and high-reliability data communication of trains under condition of high-speed movement.

The invention discloses a mobile digital broadcasting signal transmission method, and provides a framing modulation scheme in the mode that a time domain and a frequency domain are mixed. According to a training sequence optimization design method and a signal generating pattern and signal selecting method of the mobile digital broadcasting signal transmission method, original signals of OFDM signals can be easily processed, restored and acquired at a receiver end. The mobile digital broadcasting signal transmission method has the advantages that the peak-to-average power ratio is low, synchronization time is short, channel fading can be resisted, and multiple services can be controlled.

The invention discloses a transmission method of anti-fading mobile digital broadcasting signals. The transmission method is a framing modulation scheme with time domains and frequency domains being mixed. By means of the training sequence optimization design, the signal generating models and a signal selection method of the transmission method of the anti-fading mobile digital broadcasting signals, original signals of OFDM signals can be easily obtained at a receiver end through processing and restoring, and the transmission method has the advantages of being low in PAPR, short in synchronization time, channel fading resistant, capable of controlling multiple services, and the like.

The invention discloses an anti-fading framing modulation method for wireless signals of a multimedia broadcast, and relates to a mixed framing modulation scheme of the time domain and the frequency domain. According to the cascade interleaved coded modulation, the training sequence optimization design, the signal generating scheme and the signal selecting method of the anti-fading framing modulation method for the wireless signals of the multimedia broadcast, OFDM signals can be processed and recovered at a receiver end easily to obtain original signals of the OFDM signals. The anti-fading framing modulation method for the wireless signals of the multimedia broadcast has the advantages of being low in peak-to-average power ratio, short in synchronization time, resistant to channel fading, multiple in controllable service and the like.

A synchronous operation device consists of light tube, natural vibration converting circuit, sampling and frequency generating circuit, detection and feedback circuit, adjusting circuit and voltage dropping circuit. It is featured as sampling natural vibration frequency by preset sampling point in natural vibration converting circuit or by preset sampling point of said converting circuit and voltage dropping circuit to make control signal outputted from adjusting circuit synchronize to natural vibration frequency for improving ripple phenomenon of high voltage output.