Development of a Multifunctional Pulse Generator for High Frequency Ultrasound Imaging System

  • 柯 銘揚

Student thesis: Master's Thesis

Abstract

This paper presents a development of a multifunctional pulse generator for high frequency ultrasound imaging system which includes short pulse signal and coded pulse signal Currently the short pulse is commonly used in high frequency ultrasound imaging system since it has wide bandwidth with high resolution However the energy would severely attenuate while applying ultrasound tissue imaging The attenuation will lead to the decrease of penetration depth and signal-to-noise ratio Hence to improve the effects of attenuation bipolar pulse is developed However the decrease of bandwidth could deteriorate the system resolution In recent years chirp coded pulse is used as the excitation pulse for high frequency ultrasound imaging system to improve the attenuation of high frequency By elongating signal length chirp pulse increases mean power to improve the penetration depth and SNR However it would reduce bandwidth and resolution while elongating signal length So chirp pulse must work with pulse compression in back-end signal processing for increasing the penetration depth SNR and resolution This multifunctional pulse generator system is designed based on FPGA and high speed DAC which facilitates compact and cost-effective implementation The reconfigurable structure is competent for various applications; moreover it opens a platform for future research and development When evaluating imaging system waveform analysis and frequency domain analysis are presented; the system and the instruments for commercial use are compared The efficiency of the system compares favorably with the instruments Furthermore the results show that the coded pulse signal can acquire 21dB increase of SNR and 400% increase of penetration depth in contrast with unipolar pulse Finally with the help of compression filter chirp pulse can efficiently enhance the penetration depth with a minimal sacrifice of axial resolution
Date of Award2015 Aug 5
Original languageEnglish
SupervisorTainsong Chen (Supervisor)

Cite this

Development of a Multifunctional Pulse Generator for High Frequency Ultrasound Imaging System
銘揚, 柯. (Author). 2015 Aug 5

Student thesis: Master's Thesis