The Transmitting Equipment Designing Of The NMR And TEM Associated Instrument

Water is important to people on the earth. The water distributing is not the same in many places. The lack of water is obvious in our China and it influences our development and people'life. Detecting underground water is an effective way to solve the water problem.There are many underground water detecting methods. The SNMR(Surface Nuclear Magnetic Resonance ) and the TEM(Transient EM) are two effective methods. The combination of the two methods can give more correct results.The combination of the two methods can get more accurate result of the underground water portrait, and the precision of profile can be improved more.SNMR method is a direct water detecting method, but the exploration depth is less than 150 meters. The instrument first works in SNMR method when the exploration depth is less than 150 meters while the transmitter of the instrument transmit the 40ms alternative current signals. The H proton of the underground water then will be inspired and generate the weak NMR FID signal. The transmitting frequency is near to the Lamor frequency. The NMR signal is then picked up by the receiving coil. The exploration depths of TEM method will be 0-400 meters or more. When the exploration depth is above 150 meters, the instrument works in TEM method and transmits the TEM signal. The receiving coil will receive the signal by the underground object and gives out the useful information.The SNMR and TEM instrument have some same configurations which will be useful to the combined machines.1,The transmitters of the two instruments are both made up of the transmitting control module, the drive module and the main transmitting circuit. 2,The main transmitting circuit is both composed by the H bridge made up of power switches.And we can use one multifunctional transmitter to realize the two kinds of wave transmitting.The first chapter introduces the significance, application and study condition both native and abroad. The second chapter analyzes the basic theories of the two exploration methods. The next chapter introduces the design and realization of the main transmitting circuit. The forth chapter gives the simulation result of the transmitting circuit. The fifth chapter gives the testing result of the multifunctional transmitter. The last chapter summarizes the whole paper.The multifunctional transmitting instrument realizes such functions:Transmitting frequency: 1 - 4 kHz. The time and frequency of transmitting current pulse is controlled by software program. The duration of transmitting current is 5-40ms and the maximum transmitting current is 450A.