Signal processing method and realization of vortex flow meter
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摘要: 设计一种基于变增益运算放大器和带通开关电容滤波器的新型涡街流量计信号处理电路.单片机利用模拟数字转换电路(A/D)实时检测涡街流量计传感器输出信号的幅度和频率,同时利用数字模拟转换电路(D/A)对变增益运放进行控制,为后续的信号检测电路提供幅度相对稳定的有效信号.带通开关电容滤波器在单片机的控制下实时跟踪变增益运放输出的信号频率,保证带通滤波器的中心频率接近信号频率,以达到良好的滤波效果.滤波后信号通过单片机进行频率信息的精确计算以及流量的解算.实验结果表明,变增益运算放大电路有效解决了涡街流量计传感器输出信号幅度变化范围大而造成的放大电路复杂,分段放大信号幅度不连续等问题;带通滤波器通过单片机实时调整中心频率,对信号中各种干扰起到较好滤波效果.Abstract: A new method of vortex flow meter based on variable gain amplifier and band pass switched-capacitor active filter is designed. The singlechip processor measures the range and frequency of the vortex flow meter output signals by the inner analog to digital converter (A/D), and the gain of the variable gain amplifier is controlled by the digital to analog converter (D/A) of the processor, then the relative stable active signal is provided to the subsequent measurement circuits. The band pass switched-capacitor active filter traces the frequency of the variable gain amplifier output signal, it is guaranteed that the center frequency of the band pass filter is near to the signal frequency, so the favourable filter result is obtained. The frequency of the filtered signal and the flux of the liquid are calculated by the processor. The experimental results show that the complex amplifier circuit due to the large variable range of the vortex flow meter output signal is replaced, and the discontinuous problem of the signal is solved. The noise of the signal is effectively restrained because that the center frequency of the band pass filter is adjusted by the processor.
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Key words:
- sensors /
- vortex flow /
- operational amplifiers /
- bandpass filters
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