Design of Filtering Electrocircuit of Test System Using for Speed Measurement of the Engine

This paper introduced the general design method of the bandpass filter, and according to the requirement of some type inspecting instrument, the paper proceeded the design. The filtering electrocircuit is small, light and cheap, it suits to use the A/D cards collect directly. Through the actual operative verification, it completes the filtering function goodly, what is more, the electrocircuit is stable and reliable.