基于示波器的相位调制信号频率测量方法

Frequency Measurement Method of Phase Modulation Signal Based on Oscilloscope

在低成本的前提下,针对示波器测量中低频相位调制信号的频率,提出3种频率测量方法。时域频率测量法在时域上通过测量周期得到信号频率;频域频率测量法在频域进行FFT得到信号频率;平均采样频率测量法在时域对信号作时域平均再测量周期得到信号频率。通过原理分析和试验对比,解决了基于示波器测量相位调制频率误差大的问题。结果表明,平均采样频率测量法为相位调制信号示波器频率测量的最优方法。

In base of low cost,aiming at oscilloscope measuring frequency of low and medium frequency phase modulation signal,three kinds of measurement methods for phase modulation signal are proposed.The period is used to acquire the signal frequency by means of a time-domain frequency measurement technique,whereas the frequency domain for FFT is obtained through a frequency-domain method.Average sampling frequency measurement method makes the time domain signal in time domain average to get the period to obtain the signal frequency.Through theory analysis and experiment contract,the problem of the great error in the measurement based on the phase modulation frequency measurement by oscilloscope is solved.The results show that the average sampling frequency measurement method is the optimal method for frequency measurement of phase modulation signal by oscilloscope.