Ultra Low Noise Analog Amplifier for 3D Resistivity Acquisition System

Abstract

An ultra-low noise analog amplifier for a three-dimensional resistivity data acquisition system, including two parts, the first part is a direct-coupled voltage series negative feedback ultra-low noise amplifier composed of six transistors, and the second part is composed of three operational amplifiers low noise amplifier. In the first part, the emitter of the second stage provides a bias current to the base of the first stage. While obtaining the bias current, a DC negative feedback is introduced to make the static operating point of the circuit more stable. Adding to the bias current feedback circuit The capacitance is added, which greatly improves the input impedance of the amplifying circuit; the second part is two non-inverting input universal integrated operational amplifiers with highly consistent performance parameters, with double-ended signal input and only single-ended signal output, common mode rejection ratio Very high, it has a very good effect on electromagnetic field interference suppression, and can make the measurement accuracy below 0.1μV, which can greatly reduce the weight of field sending equipment and receiving equipment, and greatly improve the efficiency of electrical exploration work.

Description

technical field [0001] The invention belongs to the technical field of geophysical exploration, and relates to an ultra-low noise analog amplifier used in a three-dimensional resistivity data acquisition system in the technical field of resource and environmental exploration. Background technique [0002] The three-dimensional resistivity data acquisition system belongs to the direct current method exploration instrument. The development of direct current prospecting instrument technology is inseparable from the development of electric prospecting theory, electronic technology, signal processing technology and computer technology. Direct current prospecting instruments have gone through a development process similar to other instruments, from mechanical to electronic tube and transistor stage, to integrated circuit and microcomputer control stage. [0003] With the gradual development of mineral resource exploration to the deep, the required exploration depth is getting lar...

AI Technical Summary

Problems solved by technology

[0004] The working conditions of direct current prospecting instruments are in the field, especially for mineral resource exploration, which may be in areas with high mountains, dense forests, and criss-cross rivers, or desert areas with few people. The heavy transmitter equipment reduces work efficiency and even makes it impossible to carry out work.

In the direct current method prospecting instrument system, in order not to make the high-voltage, high-current transmitter power too large and make the equipment too heavy, it is necessary to improve the measurement sensitivity and measurement accuracy of the instrument receiver, and to improve the sensitivity and accuracy of the instrument receiver. Accuracy, the noise of the pre-amplifier in the instrument must be as low as possible, and the current domestic similar product instrument receiver measurement sensitivity and measurement accuracy are in the order of 0.1-0.9mV

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