The Weak Signal Detection In Electrical Resistance Tomography Testing System

Two-phase flow widely exists in industry.The research on two-phase flow is developing rapidly and has been one of the frontier subjects concerned in the world. However, two-phase flow measurement is difficult owing to its complexity. In many cases, its measurement technique is the bottle neck of the development of research on two-phase flow.The Electrical Resistance Tomography ( ERT ) technique used in two-phase flow measurement can obtain the flow characteristic by measuring the change of conductivity in the sensing field.It has a great potential in industry applications.The data-acquisition of an ERT system determines whether the system is functional and hence is crucial to the whole system.Due to that ERT data acquisition dealing with weak signal detection, it is very difficult and challengingThis paper reports a research performed on ERT data acquisition system design.The design is carried out on the basis of weak signal detection theory, and on the ERT measurement principle.The design focus is mainly placed on signal source, multiplexing circuit, preamplifier, filter, phase sensitive detection, A/D conversion etc.Simulation is performed on the design to validate the feasibility and the circuit parameters using both Multisim and Proteus package.PCB board is then designed with measures taken for weak signal detection.Circuit debugging and test-result analyzing are also discussed in the paper.Finally the relevant software work on controlling the multiplexer, AGC circuit, A/D conversion and the serial data communication are presented.