Abstract: A spiral ultrasonic tomography imaging method and system are provided. The method is to use synchronous rotation of an ultrasonic probe or cyclic switching of emission array elements in the ultrasonic probe under the premise of a uniform displacement of the ultrasonic probe along the Z axis, so that the change trajectory of the positions of emission array elements over time in a three-dimensional space at each ultrasonic emission time is distributed along a spiral line or a curve. During the process of the uniform displacement of the ultrasonic probe along the Z axis, the ultrasonic probe emits ultrasonic waves and receives and collects echo data. The collected echo data is stored and post-processed to realize ultrasonic tomography imaging of an object. The spiral ultrasonic tomography three-dimensional scanning method and the corresponding system realize rapid continuous uninterrupted data acquisition to ensure that higher spatial resolution in the Z-axis direction.

Abstract: Embodiments of the present invention disclose Orthogonal Frequency Division Multiplexing (OFDM) signal generation methods, related devices, and related application systems. An example method may include: obtaining parameter information of an OFDM signal; determining N first subcarriers and P second subcarriers from M subcarriers based on a preset parameter D; separately allocating signal power to the N first subcarriers and the P second subcarriers in two phases, to determine waveforms of the two phases, that is, a first waveform and a second waveform; and generating an OFDM signal including waveform symbols of the two phases.

Abstract: This application provides a wireless sensing method and an apparatus. The method includes: A first communication apparatus receives a first signal and a second signal based on a first transmission parameter set and a second transmission parameter set respectively, and performs sensing based on the first signal and the second signal, to obtain a sensing result. The first transmission parameter set corresponds to the first signal, at least one parameter in the first transmission parameter set meets a first condition, and the first condition is related to a targeted ranging coverage; and the second transmission parameter set corresponds to the second signal, at least one parameter in the second transmission parameter set meets a second condition, and the second condition is related to targeted sensing precision.

Abstract: A transmit end receives a first ranging parameter from a receive end, where the first ranging parameter is received in an Nth time of ranging, and the first ranging parameter includes first ranging precision of a ranging signal and/or a first signal-to-noise ratio of the ranging signal (S310). The transmit end determines a first ranging waveform based on the first ranging parameter (S320). The transmit end sends the first ranging waveform to the receive end (S330). The transmit end receives a second ranging parameter from the receive end, where the second ranging parameter is determined based on the first ranging waveform, the second ranging parameter includes second ranging precision of the ranging signal and/or a second signal-to-noise ratio of the ranging signal, and the second ranging precision is less than the first ranging precision (S340).

Abstract: An aspect of the present disclosure is related to a method for measuring and controlling linear chirp level of ultrafast laser pulse. The method includes steps as follows. A carrier-envelope phase-chirp (CEP-chirp) relation which serve as a chirp monitor is extracted, in which the CEP-chirp relation is generated from an ultrafast laser pulse. A linear chirp level of a target pulse is measured in response to the CEP-chirp relation. According to the measuring with respect to the linear chirp level of the target pulse, a dispersion element which the ultrafast laser pulse passes through is varied to control and stabilize the linear chirp level of the target pulse.