The Design Of Amplitude-Modulation Inductive Transducer Measurement System

The purpose of this paper is to resolve some key technologies of the amplitude-modulation inductive displacement transducer signal processing circuit with nanometer resolution, such as the design of high stability signal generating circuit; the technology of high precision digital phase-sensitive detection circuit; the technology of digital filter and linearization ,etc.This paper studies the inductive displacement transducer's structure and its measuring principle, also studies the whole classical measurement system and analyzes its merits and drawbacks according to related experimental findings. To get rid of classical measurement system's drawbacks such as low stability, narrow linear measuring range, etc. and improve measuring system's performance index, this paper's improves several key technologies in the high-accuracy measuring circuit. Also this paper designs the amplitude-modulation inductive displacement transducer signal measuring system controlled by DSP, and carries out experiments on it.The details and methods of research as follows:Firstly, analyzes the whole system's interferences, and analyzes its main interference factors in detail, such as electromagnetic interference (EMI), power disorder, etc, and gives some ways and means to avoid or weaken the interference's influence to the system. This lays a firm foundation for the measuring system design.Secondly, basing on analysis of Direct Digital Frequency Synthesis (DDS)'s principle, structure and its optimization, this paper designs a low power consumption, high stability DDS generating circuit to generate a sine wave as the driving source for inductive displacement transducer.Again, aiming at the classical phase-sensitive detection circuit's drawbacks, this paper brings forward an improved digital phase-sensitive detection method, whose structure is flexible with high detection precision.Finally, this paper finishes the amplitude-modulation inductive displacement transducer's signal processing system with USB interface to PC controlled by...