Design an inductive micro-displacement sensor whose output is frequency signal

based on planar spiral inductor and FPGA technology

and it realizes digitalized output and measurements. The system consists of displacement-inductance converter module

inductive detection circuit

frequency-subtracting module and FPGA system. In addition

it builds up soft core of NIOSⅡin FPGA system to process the acquired data. Experimental results show that this system has characteristics of good temperature stability and high sensitivity whose measuring range is 0

15 mm

the maximum error is 0. 03 mm and resolution is 10 μm in the range of 0

6 mm.