The invention relates to a low-frequency-stage magnetic sensor
background noise measuring method which is applicable to measuring the
background noise of a low-frequency-stage magnetic sensor in a wild environment or a big shielding room. The method comprises the following steps that:
response characteristics of amplitude frequencies and phase frequencies of two magnetic sensors are respectively adjusted to be accordant; the two sensors are horizontally arranged in parallel with a distance of 2-2.5m; two ends of the sensors are in parallel and level; the sensors sense identical natural
horizontal field signals which belong to relevant signals;
natural field signals can be eliminated by using a differentiation method; however, the
background noise of the two sensors refers to an irrelevant random
signal; and
signal energy after the differentiation is the sum of
noise energy of the two sensors. An average power spectrum of the signals after the differentiation is calculated, the average power spectrum is divided by 2 and is subjected to extraction of a root, and the background
noise of a single sensor is calculated according to the output sensitivity of the magnetic sensors. The background
noise of the
low frequency stage magnetic sensor in a response bandwidth is accurately measured, and compared with a theoretical
analysis method, the actual
noise level of the magnetic sensor is relatively accurately reflected.