On the basis of knowing the work principle of AFT circuit in the colour TV by remote controls, the author has detailedly analyzed the signal process among AFT circuit, microprocessor and the electronic tuning ware, and finally dissected the appearance of hitch caused by AFT circuit when it is not normal.

The current signals with splash or without splash are processed using cepstrum transform in spot welding,and then the plots of the cepstrum are compared.

Based different dealing ways of voltage and current signals in Siemens analog input modular EM231,two normal signal-proceeding programs are given after the analysis of modular inner proceed procedure in this paper.

This paper introduces that current signals of power system are acquired by Rogowski coil through optical fiber transmission system to low voltage side,which overcome the strong electromagnetic interference between the high-voltage signals,finaly transmission signals are send into the MSP430 to achieve signal measurement and display to improve the accuracy of measurement.