Measurement of the speed are measured the frequency of commonly used method (M method), testing cycle method (T method), as well as cycle times (M / T method) in the main text, so a relatively brief.

• 对转速的测量常用的有测频率法(M法)、测周期法(T法)以及多倍周期法(M/T法)文中也做了比较简单的介绍。