A filtering method for burr signal based on state machine

High frequency burr in the pulse signal is one of the most important reasons to effect the detection accuracy and reliability of signal. This paper presented and practiced a real-time filtering method of state machine, and successfully applied to some speed detection for military vehicle. The method, using CPLD as hardware and driven by high frequency clock, detects transient signal, filtered out the short pulse and output the wide pulse, so as to realize filtering. This paper introduced in detail the principle and implementation method of the state machine, and analyzed the filtering characteristic of this method. This paper validated its feasibility and influence of filtering width changes on precision by simulating its application on square signal burr.