The traditional signal processing methods that amplify , filter , rectify signal and count , which are used in vortex flowmeter now , has shortage in extracting real flow signal from noise . the methods that restrict measurement range or do n ' t measure small flow have to be adopted 目前渦街流量計所采用的放大、濾波、整形、計數(shù)的處理方式,在從噪聲中提取流量信號方面存在較大的局限性,只能采用限制量程比、不測小流量等方法來抑制噪聲。