Extremely wide-range speed measurement using a double-buffered method

An electric motor double-buffered speed measurement method for PC/AT computer application is based on 14.31818 MHz reference clock. The extremely wide frequency range of 4/spl middot/10/sup 9/ (1.67 mHz to 7 MHz) is independent of sampling time, which can be chosen from 100 /spl mu/s to 4.6 ms. Appropriate software provides real-time graphics presentation of measured speed versus time and storage for further analysis. The enclosed test diagrams cover DC motor speed reversal and an induction motor acceleration.<
>