The Design Of The Drive Sofeware Of Broadband Electromagnetic Transmitter

Borehole-ground electromagnetic method is a kind of electromagnetic method from Russia which has been applied into exploration activity recently. It was brought in China in the 1990s, and is based on the principle of"emiting under borehole, receiving on the ground"—placing the transmitter at the bottom of borehole, and then receiving the electromagnetic signal generated by electromagnetic field which is used to research the electromagnetic field and the geological condition.In order to research the borehole-ground electromagnetic method, The experiment system of physical simulation of borehole-ground electromagnetic method is needed. This system consist of broadband transmitter and receiver. In the indoor experiment, the transmitter which is used as an excitation source emitted inversed square wave with different frequence into a water tank. By reason of induced ploarization of the electrolyzer under the tank, there will be a secondary field. The tradional electromagnetic transmitter limites the frequent point chosen in the fieldwork, while theselection of the frequence of the boardband transmitter can be much more which change from 1/128Hz to 8192Hz and vary following 2n. So we have a wider frequency range and more frequency choice.To realize fuctions of transmitter, we need to develop the sofeware of control program—the drive sofeware of broadband electromagnetic transmitter. The program has three aespects:The fuctions of ARM, high level chip microprocessor, are the display of information through LCD, the input and output of commands and data via keyboard, the timing operation of timer, the syntonization with the receiver under the help of GPS, and the communication with assistant information collecting part.The main part of assistant information collection is AVR, high speed chip microprocessor with RISC. AVR was designed to collect and deposit power supply voltage, forward direction supply current, reversal supply current, and temperature inside the instrument. The assistant part also contains the program of CPLD, which is responsible for generating asistant controling signal. The program can generate accurate frequent signal by means of separating frequency for collision. This signal controls the drive circuit of IPM in order to make IPM work regularly.The program of superordinate instrument is made by LABVIEW, graphic program language. The program is supposed to control the operation of subordinate instrument. Its fuctions contain the data transfer between the superordinate instrument and the subordinate instrument and the deposit of data on computer.