基于逆重复m序列的精细探测电法发送机设计

Electrical fine-exploration transmitter design based on invert-repeated m-sequence

介绍了基于伪随机相关辨识理论的电法发送机设计思想.通过分析逆重复m序列伪随机信号的性质,产生原理,以及伪随机信号系统辨识的原理,研究了其在电法勘探应用中的可行性.用工程软件MATLAB仿真产生了逆重复m信号的波形,并分析了频谱和自相关函数,对产生伪随机信号的序列长度和时钟频率等参数的选择作出讨论,以说明其作为电法勘探场源的优良特点.作出了电法发送机系统初步设计,包括主控单元、逆变器、GPS同步,电流测量等模块,发送机信号控制单元采用硬件描述语言VHDL设计,并用CPLD可编程逻辑器件LC4256V实现了硬件产生m序列和逆重复m序列,及各种控制信号.宽频带、密频比,抗干扰能力强是其主要特点,在电法勘探中有良好的应用前景.

The design of the electrical transmitter based on pseudo-random correlation identification is introduced in this paper. By analyzing the invert-repeated m-sequence＇s characters and the method how the signal to be generated, as well as the elementary knowledge of system identification using pseudo-random signal , we studied the feasibility of electrical prospecting using invert-repeated m-sequence. Using MATLAB, we generated m-signal and invert-repeated m-signal, and analyzed their spectrums and autocorrelation function. How to select the parameters including the length of sequence, clock frequency, and so on, is discussed. Its excellent specialities as the signal source of electrical prospecting are showed. We have designed the prototype of the electrical exploration transmitter. It includes the main control unit, power inverter unit, GPS synchronization unit, current measure unit, and so on. The control unit is designed using VHDL. Based on CPLD LC4256V, the m sequence, invert-repeated m-sequence and other control signal are generated in hardware. Wide band, dense frequency and high anti-jamming ability are the transmitter＇s main features. In a word, the paper has proved the good prospect of its application on electrical exploration.