基于LabVIEW的低频信号频率测量

在对汽车底盘实验台架变速箱的输出轴进行转速测量时,通过测取霍尔传感器输出的脉冲信号的频率得到转速值,而使用LabVIEW内部子VI无法准确测量低于1Hz的信号的频率。为解决这一问题,提出了用测波峰之间时间和测时间段内波峰数两种方法测量低频信号的频率。使用仿真信号比较了两种方法测量的准确性,结果表明,用测波峰之间时间的方法得到的测量结果更为准确。用该方法对变速箱输入输出轴转速进行了测量,得到了比较满意的结果。

The Frequency Measurement of Low-frequency Signal Based on LabVIEW

During the measurement of the gear box＇s output shaft on automobile chassis experimental bench,rotation rate is got by measuring the frequency of the signal impulse outputed from the Hall sensor.But using LabVIEW sub-VI can not accurately measure the signal frequency below 1Hz.In order to solve this problem,two kinds of methods are put forward to measure the frequency of low-frequency signal,that is,measuring the time between crests or crest numbers during a time.Simulation signal is used to compare precision of two methods.Finally,the result indicates that the method which measures the signal frequency between crests is more accurate.A satisfying result is achieved by using this method to measure the input and output shaft speed in gearbox.