近地表探测多频信号产生技术  

Multi-frequency Signal Generating Technology for the Shallow Surface Detection

作　　者：刘长胜[1] 康盼 夏正阳[1] 王金玉[1] 张伟[1] 周继瑜[1] 

机构地区：[1]吉林大学仪器科学与电气工程学院,长春130026

出　　处：《长春理工大学学报（自然科学版）》2013年第5期112-115,共4页Journal of Changchun University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金(41004027);吉林省科技发展计划重点项目(20100349)

摘　　要：针对近地表频率域电磁探测对发射信号的要求,以直接数字频率合成技术为理论基础,利用单片机与可编程数字逻辑器件FPGA构建硬件控制平台,设计具有通用性的多频信号产生系统,实现单频及多频(双频、三频等)正弦信号的产生。经验证,该方法产生的波形可控性强、谐波失真低、分辨率高,克服了位流法对线圈负载稳定性要求高,伪随机法不能任意设定频率并且THD(总谐波失真)高的缺点。In this paper, in order to meet the requirements of the transmitting signal in shallow surface FEM do-main, based on the DDS theory, using single-chip microcomputer and programmable logic device as the hardware control platform, the universal multi-frequency signal generating system is realized. A single frequency, multi-fre-quency （dual-band, tri-band） sine signal can be produced in this system. The experiment results show that, wave-forms produced in this way have good quality, pure frequency spectrum and high resolution. Some other methods’ defects can be overcome, such as the high requirement of stream method to the stability of coil load and the pseu-do-random method which cannot arbitrarily set the frequency and the higher THD （total harmonic distortion） . Theoretical simulation and experimental results verify the effectiveness of the method.

关 键 词：频率域 直接数字合成 近地表 多频信号 

分 类 号：TH763[机械工程—仪器科学与技术]