Noise Characteristics of Air Core Transient Electromagnetic Sensor
Yujie Wang, Zixiu Liu, Shuang Zhang · International Conference on Electric Information and Control Engineering · 2012
Transient electromagnetic sensor is widely used in detecting very weak signal. Noise is a primary factor affecting the sensitivity. In this work, equivalent circuit of sensor coil and preamplifier with noise sources is described. The calculation of each noise contribution at output node which includes Johnson noise of total resistance, the noise voltage source and the noise current source are solved. Then the expression of the total noise is given. With frequency dependent noise discussion, the main effect of noise to the whole design are obtained, many suggestions to reduce the noises are presented. It is useful to provide further and innovative study to obtain low noise transient electromagnetic sensor.