(1. 中南大學(xué) 有色金屬成礦預(yù)測(cè)教育部重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083；
2. 中南大學(xué) 地球科學(xué)與信息物理學(xué)院，長(zhǎng)沙410083；3. 長(zhǎng)沙五維地科勘察技術(shù)有限責(zé)任公司，長(zhǎng)沙 410205)
摘 要: 感應(yīng)式磁場(chǎng)傳感器一直是我國(guó)電磁法儀器發(fā)展的瓶頸，國(guó)外大地電磁法中測(cè)量大地磁場(chǎng)主要采用感應(yīng)式磁場(chǎng)傳感器。為此，根據(jù)音頻大地電磁場(chǎng)源的特點(diǎn)，從感應(yīng)式磁場(chǎng)傳感器的基本原理出發(fā)，設(shè)計(jì)傳感器的磁芯和線圈繞組結(jié)構(gòu)以及線圈的諧振頻率；另外，采用了磁通負(fù)反饋技術(shù)和頻率補(bǔ)償?shù)姆椒ǎ瑪U(kuò)展了傳感器的頻帶，得到了在1 Hz~9.8 kHz頻帶范圍內(nèi)平坦度為±1.5 dB的靈敏度曲線，滿足音頻大地電磁探測(cè)的需要。
關(guān)鍵字: 音頻大地電磁；感應(yīng)式磁場(chǎng)傳感器；靈敏度；磁通負(fù)反饋
audio-frequency magnetotelluric sounding
（1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
Central South University, Changsha 410083, China;
2. School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
3. Changsha 5D Geo-survey & Technical Co., Ltd., Changsha 410205, China）
Abstract:Magnetic field induction sensors have been the bottleneck in the development of electromagnetic devices in China. In abroad, the natural geomagnetic variations are mainly measured by magnetic field induction sensors in magnetotelluric methods. According to the characteristics of the natural geomagnetic variations in audio-frequency band and the basic principle of magnetic field induction sensors, the structure of core, coil winding and the resonant frequency of the sensor were designed. With the magnetic flux negative feedback and frequency compensation, the frequency band is extended and the flat resulting amplitude-frequency response is obtained in the frequency band of 1 Hz−9.8 kHz with the deviation no more than ±1.5 dB. It can be used in audio-frequency magnetotelluric sounding.
Key words: audio-frequency magnetotelluric sounding method; magnetic field induction sensor; sensitivity; magnetic flux negative feedback
