7 results about "Carrier frequency synchronization" patented technology

The application provides a carrier frequency synchronization method applied to a frequency hopping data transmission system, the frequency hopping data transmission system comprising a transmitting end and a receiving end, and the method comprises the following steps: the transmitting end processes to-be-sent data into a data frame, adds a pilot head based on a ZC sequence to the data frame to form a frequency hopping data transmission frame, and sends a radio frequency signal carrying the frequency hopping data transmission frame to the receiving end; the receiving end acquires the radio frequency signal, processes the radio frequency signal into a digital signal; carrier synchronization processing is performed on the digital signal, carrier frequency scanning is performed on multiple frequency hopping points to screen effective communication frequency points; the starting position of the data frame is determined according to the effective communication frequency points, data demodulation and decoding are performed on the data frame, and original data is recovered. Through the application, the excellent autocorrelation characteristics of the ZC sequence and the intelligent double-peak detection mechanism are utilized to realize carrier frequency synchronization without strict time synchronization, and fast and anti-interference data transmission is completed.

A demodulator (101) comprises a sampling stage (112), a hold stage (114), and a final stage (116). The sampling stage (112) includes at least one mixer (132) designed to be controlled by complementary clock signals synchronously with a carrier frequency of an input signal (122) in order to demodulate the input signal (122) and generate a sampled signal (126). The hold stage (114) includes at least a first capacitor circuit (134A) designed to output the sampled signal (126) as a first hold signal (128A) after delaying the sampled signal (126), and a second capacitor circuit (134B) designed to output the sampled signal (126) as a second hold signal (128B) after delaying the sampled signal (126). The final stage (116) is designed to alternately couple the first hold signal (128A) and the second hold signal (128B) as a demodulated output signal (124).

The application discloses a time and carrier frequency synchronization method and system based on joint correlation of a preamble and a prefix. Aiming at a MIMO-OFDM downlink system with one-bit quantization, the application provides a time and carrier frequency synchronization method based on joint correlation of a preamble and a prefix, which is used for realizing accurate synchronization of time and carrier frequency of the system and reducing estimation errors of time offset (STO) and carrier frequency offset (CFO). The method is as follows: step 1, calculating correlation values and ratios of a preamble symbol and prefixes of OFDM symbols except for a first symbol, the preamble symbol and a last symbol, to obtain an estimated value of the STO; and step 2, estimating a phase shift of the preamble symbol and the prefixes of the OFDM symbols except for the first symbol, the preamble symbol and the last symbol to obtain an estimated value of the CFO. The application can effectively reduce the estimation errors of the STO and the CFO, reduce a bit error rate of the system, improve system performance and has good realizability.

This application provides an inverter carrier frequency synchronization method, a power grid system, a charging pile, and a storage medium, belonging to the field of power technology. The method includes: acquiring an inductor sampling current, which is obtained by sampling a filter inductor located at the power output terminal of the target inverter according to a preset sampling frequency; determining the actual current ripple based on the inductor sampling current; and adjusting the actual carrier frequency of the target inverter in response to the actual current ripple and the theoretical high-frequency ripple component satisfying a preset carrier frequency adjustment condition. The carrier frequency adjustment condition indicates that the error between the actual current ripple and the theoretical high-frequency ripple component is within a preset component error range, so that the actual carrier frequency and the desired carrier frequency of the target inverter are within the frequency error range. This application embodiment can achieve carrier frequency synchronization between parallel inverters while considering deployment difficulty, application cost, and synchronization stability.

A demodulator includes a sampling stage, a hold stage, and an output stage. The sampling stage includes at least one mixer configured to be controlled by complementary clock signals synchronous with a carrier frequency of an input signal to demodulate the input signal and generate a sampled signal. The hold stage includes at least a first capacitor circuit configured to output the sampled signal after delaying the sampled signal as a first hold signal and a second capacitor circuit configured to output the sampled signal after delaying the sampled signal as a second hold signal. The output stage is configured to alternately couple the first hold signal and the second hold signal as a demodulated output signal.

The application provides a carrier frequency synchronization method applied to a frequency hopping data transmission system, the frequency hopping data transmission system comprising a transmitting end and a receiving end, and the method comprises the following steps: the transmitting end processes to-be-sent data into a data frame, adds a pilot head based on a ZC sequence to the data frame to form a frequency hopping data transmission frame, and sends a radio frequency signal carrying the frequency hopping data transmission frame to the receiving end; the receiving end acquires the radio frequency signal, processes the radio frequency signal into a digital signal; carrier synchronization processing is performed on the digital signal, carrier frequency scanning is performed on multiple frequency hopping points to screen effective communication frequency points; the starting position of the data frame is determined according to the effective communication frequency points, data demodulation and decoding are performed on the data frame, and original data is recovered. Through the application, the excellent autocorrelation characteristics of the ZC sequence and the intelligent double-peak detection mechanism are utilized to realize carrier frequency synchronization without strict time synchronization, and fast and anti-interference data transmission is completed.

Various techniques pertaining to carrier synchronized coordinated transmission for coordinated beamforming (CBF or CoBF) in wireless communications are described. An apparatus (e.g., a first access point (AP) ) performs negotiation with a second AP to establish or update a coordinated beamforming (CBF) multi-access point (MAP) coordinated (MAPC) agreement for a CBF MAP group including the first AP and the second AP. The apparatus then performs carrier synchronized CBF related transmissions with the second AP, with the first AP functioning as a carrier frequency synchronization reference AP in the CBF MAP group, and with the second AP functioning as a carrier frequency synchronization follower AP in the CBF MAP group which synchronizes its carrier frequency to that of the first AP for the carrier synchronized CBF related transmissions.