In the analysis methods of gear system dynamic response, time domain signal analysis method is the direct means to study the dynamic response of gear system. The use of statistical indicators for fault diagnosis also has a wide range of applications, and the effect is remarkable, for example, RMS value has a good effect in processing residual signal, and peak peak value as a measure of signal fluctuation range also plays an important role in the analysis of dynamic response signal.

Frequency domain analysis is also widely used in gear system fault diagnosis. The meshing frequency and harmonic frequency of gear system and the side frequency phenomenon caused by modulation are important characteristics of gear vibration signal spectrum. The increase of the number and amplitude of the side frequency and the regional characteristics of the side band can be used as an important basis to judge the gear fault.

The RMS value is calculated as follows:

The expression of peak peak value is as follows:

The time domain signal analysis, statistical index analysis and frequency domain analysis are used to analyze the dynamic response of the gear system to obtain some important characteristics of the gear system.