Coherentinfrasonic Frequency Band Signals Source Research

Non-traditional security issues such as international terrorism, ethnic separatism,extremism, violent crime is increasingly becoming an important challenge of building asocialist harmonious society. As a kind of soft killing and less destructive weapons ofhumanitarian，non-lethal weapons have obtained extensive development. Infrasonic wavesrefer to the acoustic frequency is lower than20Hz. Many internal organs，the resonancefrequencies of the body are also in this band. When the infrasonic wave of some strengthacted on the human body, people will be uncomfortable and even loss resistance. Infrasonicweapons which are made using this principle are non-lethal weapons. Infrasonic weaponswhich are due to some unique advantages are paid high attention by the army and police ofdifferent countries.We research a key technologie of a small portable field controlled infrasonic non-lethalweapons in this paper. In order to achieve the purpose of orientation, the non-lethal weaponsare based on a series of sub-sonic which are mutual interference. To solve the non-lethaleffects of controllable site specific needs, we need to study coherent signal source ofinfrasonic frequency band. DDS (Direct Digital Frequency Synthesis: direct digital frequencysynthesis) technology which is a leap source technology is a fully digital frequency synthesistechnology. DDS technology can achieve coherent multipath controllable real-time electricsignalsource which is needed by the weapon in a better way.We have analyzed the working principle of the controllable infrasonic non-lethal weaponswhich are being explored. The weapon is based on that signal source stimulates piezoelectricinfrasonic phased array produces mutual interference waves. Then we summarize its variousspecial requirements for signal source. On the basis of analyzing the comparison of therelevant technology, we developed an advanced, practical technical solution. Finaly, we choseFPGA equipped with some appropriate external circuit to achieve DDS system. On this basis,we conduct a Verilog program development, design, then we producted an infrasonic sourceof coherent frequency band signals. The signal source is a three-way infrasonic frequencysignal source with adjustable phase difference to each other. The signal source is easily to expand to more channels in technically. The signal source is amplitude controlled and phasecontrollable. And the signal source is a small size, low power consumption. We designe amulti-channel filter, then we study the characteristic of the frequency spectrum of the signalsource’s output. We have conducted a comprehensive and in-depth analysis of error, whichlaid a foundation for further improving accuracy. Finally, the study results this paper, isverified by simulation and experiment test. The research is successful, but we still found someproblems, and look forward to improve in the future.