发明名称 VORTEX DETECTING CIRCUIT
摘要 PROBLEM TO BE SOLVED: To automatically and continuously control a passband of a band pass filter based on a vortex frequency to synchronize the vortex frequency substantially in its center over a wide range irrespective of kinds of fluids and a bore. SOLUTION: A high-pass filter 11 and a low-pass filter 12 constituting the band filter have switched capacitors respectively, and a cut-off frequency is controlled by making switching frequencies thereof variable. A fixed low-pass filter 13 is connected further to an output of the high-pass filter 11 to detect the rough vortex frequency, and the switching frequencies of the respective switched capacitors in the both filters 11, 12 are made variable based on the detected rough vortex frequency. A passband width of the band filter is controlled thereby to bring the detected vortex frequency substantially into the center of the passband width.
申请公布号 JP2001349755(A) 申请公布日期 2001.12.21
申请号 JP20000173296 申请日期 2000.06.09
申请人 OVAL CORP 发明人 MISUMI KATSUO
分类号 G01F1/32;(IPC1-7):G01F1/32 主分类号 G01F1/32
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