Simulation Of Ultrasonic Beam Formation Technology

Array signal processing is an important research branch of signal processing,at present it has been widely used in many fields and still developing at a high speed.The purpose is to deal with the signals received by the array,enhance the useful signals,suppress the unwanted interference and noise,and extract useful signal characteristics and information contained in the signal.At present,beamforming belong to one of the signs of array signal processing and it is also called spatial filtering.The essence of beamforming is to carry out airspace filtering by weighting each element to achieve the purpose of enhancing the desired signal and suppressing the interference.In this paper,we focus on the comparative study of narrowband beamforming and wideband beamforming.Firstly,three optimal beamforming criteria are introduced in the second chapter,and the performance of the three are analyzed.In the third chapter,two methods,direct matrix inversion(SMI)and diagonal loading are introduced in this paper.The two methods are compared and simulated,and the beamforming quality is observed by changing various parameters.Then the SMI algorithm is improved,and the sample covariance matrix is obtained by sliding the snapshot data so that a lower sidelobe amplitude can be obtained with less snapshots.In the end,multi-beam formation is also performed using narrowband signals.The ISM and CSM methods are described in Chapter 4 on broadband beamforming.The basic idea is to do FFT transform for the received signal and implement beamforming in the frequency domain.The RSS and LS algorithms are mainly introduced in the CSM method,and several methods of broadband beamforming are compared and simulated in the end.