相控超声激发系统的设计

Design of Phase Controlled Ultrasound Excitation System

针对相控阵列声涡旋中的多路相控信号的激发问题,选用波形存储和窄带滤波谐振相结合的信号发生芯片MD2134实现信号的输出和功率放大,并利用FPGA编程技术控制输出信号的相位,设计了一个相位可调的8路相控超声激发系统,达到高集成度、操控灵活、相位差可控的目标.在设计中,用QuartusⅡ软件编写寄存器代码,控制信号发生电路输出带有相位差的信号,经过D/A转换和功率放大后驱动换能器形成谐振.将同步输出的8路中心频率约为500 k Hz,相位差为π/4的信号分别激励8个换能器,用示波器采集水听器所接收到的声波波形,并测量各路声波的相位差.结果表明设计系统的集成度高,输出信号幅度和相位稳定,各路声波相位差和理论结果一致,可在相控超声系统中推广和应用.

In orcder to realize the excitation of phased j r ay in acoustic vortex,a phased signed in this paper. Controlled by a FPGA,the chip MD2134 is employed to generatniques of waveform storage and njraw-lDand resonant filter witli high integration degree, flexilDle operation and controllable phase difference. The control codes of chip registers are written by Quartus ： to generate signals with the controllable phase diference. After D/A conversion and power amplification, the output signals are used to drive the transducer effectively, to generate electrical resonance to drive acoustic waveforms. 8-channel synchronous signals at the the phase diference of π/4 ae used to drive 8 transducers. The corresjDonding acoustic signals are detected by a needle hy-drophone and collected by an oscilloscope to conduct waveform comparison. The consistent phase diferences of thie experi-mental results demonstrate that thie designed system is highly integrated withi stable amplituacoustic signals, and that the system can be applied in phase controlled ultrasonic system.