Research Of Coded Excitation And Signal Reception Processing System Of Ultrasonic Endoscope System

The endoscope ultrasound system (EUS) sends the probe into the human bodythrough biopsy forceps channel of electronic endoscopy. Rely on multi-source arrayprobe or rotating probe to get the image of human body tissue. It can avoid the affectsof the subcutaneous fat effectively. Without the potential radiation hazards, it can findcancer and small tumors at the first time. It is one of the best ways to diagnosispathological of human organs. The EUS is used in clinical diagnosis and treatment ofmany diseases widely.In order to improve the ultrasound endoscope system’s probing depth, resolution,and image quality, EUS generally applies coded exciting technique. In order toprovide a good foundation for the high-resolution ultrasound images, we need todesign the ultrasonic echo reception and coding circuits with high signal to noise ratio(SNR) and wide adjustable gain.The main researchs of this dissertation are shoun as the following:1. This dissertationr takes ‘half-bridge circuit’, which is widely used in thedesign of the switching power supply circuit，into the EUS coded excitation circuit forthe first time. And the circuit could generate positive and negative high voltageexcitation pulse from only one positive voltage power source. Meanwhile it canidentify the ultrasound probe automatically.2. We devided the system into two parts, the coding exitation and the signalprocessing circuit. Do the preprocessing and pre-amplification on the exitation board.Finish the deep processing on the other circuit.3. During the experiment, the coded signal which is emitted by the synchronouscoded excitation circuit is consistent with the theoretical pattern. Through the humanbody phantom experiment, we obtained34dB signal–to-noise ratio echo waveformwith amplitude of1.0Vpp, noise20to30mVpp. Waveform and simulation resultsare consistent.