基于FPGA和DSP的气体超声流量计驱动和数字信号处理系统

采用FPGA+DSP双核芯结构,研制气体超声流量计驱动和数字信号处理系统。利用FPGA很高的工作频率和丰富的内部资源,实现高速DAC和ADC的驱动控制和数据存储;利用DSP的高速运算能力,实现数字信号的实时处理。针对利用正弦波驱动产生的超声波回波信号,基于实验数据统计,提出跟踪回波信号峰值的可变阈值法,准确地提取特征波,有效地克服了噪声的影响,扩展了量程比。气体标定实验结果验证了方法和系统的有效性。

A Driving and Digital Signal Processing System of Ultrasonic Gas Flow-meter Based on FPGA & DSP

The driving and digital signal processing system of ultrasonic gas flow-meter based on the FPGA & DSP dual core structure was developed.It is realized by taking advantage of the high operating frequency and abundant resource inside FPGA to control the high-speed ADC & DAC and storage the data.On the other hand, the implementation of real time digital signal processing relies on the use of high-speed computing capacity of DSP.To address the ultrasonic echo signals generated by the use of sinusoidal excitation, a new method called variable threshold tracking the peak of the echo signal is proposed, based on the experimental data statistics.It aims at extracting the characteristic waves and weakens the influence of noise.The effectiveness of the system and method was verified by the results of gas calibration experiments.