Three approaches to obtain the average total transmission error(TE) per driving or driven gear and average tooth-tooth TE are derived from the mechanical rotation characteristics at gear meshing, by the TE measuring modal using single flank rolling test method which is constructed on the rotary encoders. One pulse time domain method to analysis TE curve, aimed at its leap defects on time domain, is proposed to make the spectral conversion and analysis possible. The deviations and the frequencies of various ...