The Research Of The Hardware For The SLF Under-well Communication System

The technique of large power super low frequency communication is attached great importance as a new research field in current international situation. It is a truth that the large power super low frequency communication systems can be widely used in several kinds of circumstances, such as, under-well, underground, underwater, earthquake monitoring, nucleus scrap processing, and environment protection application, etc.As a matter of fact, the under-well super low frequency communication is not very mature in our country. The research and development of the under-well super low frequency communication system is achieved in this thesis due to the practical needs of the under-well communication. First, the overall scheme of the super low frequency communication systems is given in this thesis. Then, the sample machine is implemented by the help of modern EDA tools and single-chip technique. The sample system is composed of three parts, that is, under-well machine, user interface machine and signal detector. The communication methods between the under-well machine and user interface machine is digital pulse width modulation (PWM).The sending repetition frequency of the under-well machine is less than 100Hz. The under-well machine is composed of microcontroller, logic circuit , the design of the power, the power of converting circuit ,digital power amplifier and enable circuit. The standard RS232 port is used for the communication of the under-well machine, which makes the communication more stable and accurate.There is a limit in the installation of the under-well hardware, that is the width of the printed circuit board is no more than the inner diameter, which value is 36 millimeters. The user interface is made up of microcontroller, filter and amplifier. The communication between the user interface and computer is achieved by standard RS232 port. The microcontroller, filter, amplifier and liquid display module (LCM) constitute the signal detector. The user interface machine exhibit the ability for extension and can be cut or added some new functions. The working state of the under-well machine can be detected by the signal detector. The sending repetition frequency also can be measured and display by the signal detector.The result for debugging experiment of the systems is given in the thesis, which shows that the system works well for expected functions. The improved methods for future development are given in the thesis.