基于LabVIEW的多采样率数字滤波器1/3倍频程计算方法

利用多采样率数字滤波器法计算噪声1/3倍频程谱在硬件上设计困难。因此为降低设计的难度,提出基于LabVIEW实现多采样率数字滤波器法计算1/3倍频程。信号首先通过抗混叠滤波器降低信号频谱混叠,然后经过降采样减少数据计算量,最后利用数字带通滤波器实现通带内信号的能量衰减并进行均方根计算得到1/3倍频程谱值。通过Lab VIEW设计出FIR抗混叠滤波器和8阶巴特沃斯IIR数字带通滤波器,并在此基础上结合声卡搭建噪声分析系统完成1/3倍频程计算。结果表明,所设计的系统能快速准确地计算1/3倍频程谱值,得到理想的低频处频谱分析。

The Multirate digital filters for 1/3 octave calculation based on LabVIEW

It is difficult to use Multirate digital filters to calculate 1/3 octave spectrum on hardware. Using LabVIEW to realize Multirate digital filters is proposed in order to reduce the difficulty. At first reducing the spectrum aliasing of signal through anti aliasing filter ,then computation is eased by down sampling. RMS is used to calculate 1/3 octave spectrum after attenuating the passband signal energy by the digital passband filter. FIR anti aliasing filter and 8 order Butterworth IIR digital band-pass filter of Multirate digital filters are designed through LabVIEW, and on that foundation, noise analysis system is built with sound card to get 1/3 octave spectrum. Experiments indicates that the system is not only fast and accurate, but also gets the ideal analysis of low frequency .