在当代许多电子信息系统中,信号源的性能参数往往对系统的功能起着决定性作用。采用直接数字频率合成技术(Direct Digital Synthesize,DDS),基于现场可编程门阵列(Field-Programmable Gate Array,FPGA)设计了能同时输出4路信号的高精度...在当代许多电子信息系统中,信号源的性能参数往往对系统的功能起着决定性作用。采用直接数字频率合成技术(Direct Digital Synthesize,DDS),基于现场可编程门阵列(Field-Programmable Gate Array,FPGA)设计了能同时输出4路信号的高精度信号发生器。同时依靠串口通信的方式,通过PC端的控制界面实时调节系统输出信号的频率、相位和死区时间。展开更多
The feasibility of a new full bridge high intensity focused ultrasound(HIFU) amplifier system with harmonic cancellation is evaluated in this study. Harmonic cancellation technique is applied to these power amplifiers...The feasibility of a new full bridge high intensity focused ultrasound(HIFU) amplifier system with harmonic cancellation is evaluated in this study. Harmonic cancellation technique is applied to these power amplifiers, which can eliminate the 3rd harmonic and all even harmonics. Since this technique requires two channels of phase signal to control one channel of power amplifier, the signal generator is required to double its output. The transducer array proposed in this study has 100 elements. So we choose an FPGA chip to generate 200 driving signals, and each channel has a phase resolution of 2ns, less than 1°. The phase signal from the FPGA meets the requirement of driving the power amplifiers. The output waveform of one channel of power amplifier(voltage across the transducer) is evaluated, and shows fewer harmonic components.展开更多
文摘在当代许多电子信息系统中,信号源的性能参数往往对系统的功能起着决定性作用。采用直接数字频率合成技术(Direct Digital Synthesize,DDS),基于现场可编程门阵列(Field-Programmable Gate Array,FPGA)设计了能同时输出4路信号的高精度信号发生器。同时依靠串口通信的方式,通过PC端的控制界面实时调节系统输出信号的频率、相位和死区时间。
基金the National Natural Science Foundation of China(No.30800246)the Shanghai Key Technologies R&D Program of China(No.09441900500)the Research Program of Shanghai Education Commission(No.14CXY05)
文摘The feasibility of a new full bridge high intensity focused ultrasound(HIFU) amplifier system with harmonic cancellation is evaluated in this study. Harmonic cancellation technique is applied to these power amplifiers, which can eliminate the 3rd harmonic and all even harmonics. Since this technique requires two channels of phase signal to control one channel of power amplifier, the signal generator is required to double its output. The transducer array proposed in this study has 100 elements. So we choose an FPGA chip to generate 200 driving signals, and each channel has a phase resolution of 2ns, less than 1°. The phase signal from the FPGA meets the requirement of driving the power amplifiers. The output waveform of one channel of power amplifier(voltage across the transducer) is evaluated, and shows fewer harmonic components.
