FPGA-based smart sensor implementation with precise frequency to digital converter for flow measurement

The realization of integrated frequency-based smart sensor for flow measurement requires a precise frequency to digital converter. A VHDL-based implementation of such converter for a royalty-free solution with 1 ppm resolution is reported. This work is part of a correlator under development to measure total flow of multiphase fluids. This intellectual property block can also be used with other frequency encoded transducers. The converter has been prototyped with a Xilinx™ XC3S500E Spartan-3E FPGA, and has been tested up to 10MHz.