关键词: 中频强磁场；误差分析；优化设计；平均值滤波；放大倍数

Abstract: By analysing the operating condition of space point measurement of IF strong magnetic field and computing the error of signal processing circuits, it finds out the major factors leading to errors. In order to improve the accuracy of the measuring instrument, real time property and antiinterference ability, an optimization method of combining hardware and software is presented. In the signal regulating circuit, the errors were significantly reduced by reasonably configuring the amplification factors of pre and post stage, relative resistor and using highprecision operational amplifier. Interference was suppressed effectively by employing two hardware and uniquely mean filtering methods. Via the use of the least square method to optimize data fitting parameters, errors caused by rectifier, filter and programmable amplifier circuit were reduced further, which improved the whole performance. The experimental results obtained by testing the optimized measuring instrument, show that measurement error is less than ±1.5%, consistency error is less than 1%, and real time property of measurement is also improved, which demonstrates the excellent effects.

Key words: intermediate frequency strong magnetic field; error analysis; optimizing design; average filter; magnification