Increment magnifying type signal measuring device using for impedance imaging

Abstract

The present invention relates to an increment amplifying type signal detecting device used in resistance imaging. The invention comprises an electrode array (1), a switch array (2), a signal generating circuit (3), an analog and digital transferring circuit (4), a voltage and current converting circuit (5), a voltage scale adjusting circuit (6), a voltage filtering and amplifying circuit (7), a difference computing circuit (8) and a central control processing circuit(9). Additionally, the invention has a probe case containing combined electrode and detecting circuit, which greatly shortens distance between the detecting circuit and the electrode, reduces unfavorable effects to signal detecting caused by capacitance on lead, distributed inductance and various electromagnetic interference. By amplifying increment during measurement, one can acquire high measuring accuracy with analog and digital converter of lower resolution.

Description

Technical field: [0001] The invention relates to a signal measuring device, in particular to an incremental amplification signal measuring device for electrical impedance imaging. Background technique: [0002] In the electrical impedance imaging technology, the method of applying excitation current to the measured object and detecting its surface potential is generally adopted. The injection of the excitation current and the pickup of the surface potential are realized through a set of electrodes that are in direct contact with the measured object. In a specific current excitation mode, the potential distribution on the surface of the measured object depends on the internal conductivity distribution of the measured object, that is to say, the surface potential of the measured object contains the information of its internal conductivity, thus through a specific algorithm The conductivity distribution inside the measured object can be inversely deduced to realize electrical ...

AI Technical Summary

Problems solved by technology

[0004] In the existing electrical impedance imaging system, the electrodes are usually separated from the measurement circuit, and they are connected by a long cable. This method will have adverse effects on the injection of the excitation current and the measurement of the surface potential.

On the one hand, the distributed capacitance and distributed inductance of the cable will cause the attenuation of the excitation current, and the attenuation is uncontrollable, so it will not be possible to ensure accurate injection of the excitation current; The voltage on the surface of the measured object itself is very weak, which makes the accurate measurement of the voltage more difficult

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