A New Inductive Coupling And Digital Filtering ECT System

Electrical capacitance tomography is essentially a process tomography technology to measure the dielectric constant distribution in the state space based on the principle that capacitance has sensitive mechanism.ECT system has the advantages of non-intrusion,fast response and low cost.It can provide visual information in closed pipelines and containers.In the long run,this technology has good development potential and wide application prospects.However,there is still much space for improvement in the accuracy of ECT system measurement.Aiming at the inaccuracy of data measurement in ECT system,a new type of ECT system with inductance coupling and digital filtering is proposed by analyzing the structure and working principle of data acquisition system.The system includes AC excitation signal amplifier circuit,adjustable voltage converter circuit,C/V conversion circuit,gain programmable amplifier circuit,phase sensitive demodulation circuit,low-pass filter circuit and reference signal amplifier circuit.The system generates the excitation signal by controlling the sinusoidal AC voltage.Before the polar plate capacitance signal enters the C/V conversion circuit,static and noise suppression of signal by inductively coupled circuit with special micro transformer.The signal is amplified,demodulated and filtered by programmable amplifier circuit,phase sensitive demodulation circuit and low-pass filter circuit.Finally,the simulation results show that the designing improves the measurement accuracy of the ECT system.