Design Of High-Density Electrical Measurement System Base On The Mixing Encoding

High-density electrical prospecting system plays a very important role in the field of geophysical prospecting today. The of the traditional high-density electrical instrument on the measurement method to a large extent limit its applications. In order to expand the high-density electrical equipment applications, the instrument from the ground is poor, especially in urban areas surrounding exploration, urban and rural residents was severely disrupted electricity and power lines and other equipment, and even lead to ineffective measure It does not work. The latest available technology is based 2n(n is odd) m pseudorandom sequence encoded electrical mixer emission technology, which completed the first launch in the purpose of mixing transmitted and m pseudorandom sequence encoded in frequency logarithmic coordinates are equidistant conducive ground for exploration. But the pseudo-random code also has several limitations: first pseudorandom encoding clocked While logarithmic axes are equidistant, but the frequency between adjacent frequency is increased exponentially, resulting in high-density electrical probing depth point span is too large, poor resolution; in addition, from the pseudo-random coding spectrum can be seen, the band of the encoded signal is narrow, to some extent, is not conducive to the noise elimination process late.In this paper, provides the basis for the various parts of the hardware-based hardware circuit structure and encoding of the transmission system mixing high-density electrical measurement system design on for less than the above high-density electrical measurement system proposed the existence of a high-density electrical method measuring systems transmit mixer waveform coding method. This method has the following characteristics: Because mixing code generator is based on a random Gaussian white noise signal and the desired frequency signal is superimposed on the formation of so called Gaussian mixing encoding this encoding. The encoded signal bandwidth, since a good correlation, hardly correlated with other signals, so there is a strong anti-jamming capability, conducive to late signal noise elimination process; and greater flexibility to the root of the n frequency provided as needed over a wide frequency range, to achieve the purpose of mixing launch conducive induced polarization properties of the observed ground electrode, and the ability to customize a mixer to improve coding for a deep exploration of the resolution of high-density electrical measurement systems transmit waveform the method, in particular, is a high-density electrical measurement system based on random Gaussian white noise emission custom mixing waveform coding method. Gauss realized mixing coding applications in high-density electrical measurement system.The overall design of the system includes hardware design overall system principles, system hardware design and launch receiving system. Transmission system mainly by the MCU control circuit, a power conversion circuit, a driver circuit isolation, current protection circuit, surge voltage absorbing circuit and grounding resistance measurement circuit. Its implementation can transmit a coded signal including an arbitrary mixing Gaussian pseudorandom encoding including encoding and by 1,0,-1 ternary digital code composed. Hardware acquisition system primarily by the signal conditioning circuit, AD7760 analog conversion circuit, FPGA controller and a USB controller circuit. Its implementation on the transmit signal acquisition speed according to different settings.