Design And Implementation Of Ultrasound Coded Excitation System

In the field of ultrasound imaging, since the limit of the average sound powerand SNR, it’s difficult for us to improve the penetration and resolution of ultrasoundimaging system. However, in theory, the coded excitation technology can be appliedin ultrasound imaging to to increase the average emission suound power and SNR.So, coded excitation is becoming a hot issue in the field of ultrasound imaging.In this context, an ultrasound coded excitation experiment system is designedand is used to do experiments for researching the feasibility of applying codedexcitation to ultrasound imaging.This thesis adopts FPGA as the core unit of front-end and adopts NI dataacquisition card as the core unit of back-end to design the ultrasound codedexcitation experiment system. Front-end part includes front-end ultrasoundhardware board design and FPGA timing logic design. Hardware circuit inc ludesFPGA system circuit，transmit circuit，high voltage switch circuit, preamplifier andgain compensation circuit, then the debugging basis on these circuits is done and thetest results are presentd which can verify the accuracy of the design. FPGA timinglogic design includes clock controller, scan controller, TGC controller, code memory,pulse emission controller, acquis ition trigger controller, switching power supplycontroller seven modules and timing simulation is made to verify the accuracy of thetiming logic design. The back-end PC software is designed using LabVIEW,including NI acquis ition card collection drive, the echo signal processing andhuman-computer interface design.Finally, the coded excitation physical simulation is done based on theexperimental system platform that had been designed. Finish coded excitationwaveform simulation and target model imaging simulation with Field II ultrasoundsoftware, in which excitation signals are Barker codeo ando Golay code withdifferent lengths and pulse compression method are inverse filtering method. By theanalysis and comparison of the experimental results and the Field II simulationresults, it can be verified that the coded excitation can be used in ultrasound imagingwhich improves the average the average transmitted power and enhance the SNRgain.