The Research Of Airborne Assembling And Communication System

In airborne operations,airborne are scattered after landing , and they are not familiar with the terrain. For the rapid build-up, they must use of high-performance direction-finding equipment and high anti-interference ability, high degree of confidentiality of communications equipment. The main task of this project is developed an airborne assembling and communication system, it operate at 50-150MHz.This system will be mainly used in complex terrain environment, for the characteristics this paper designed the system structure. This paper compared the characteristics of several direction-finding system, discussed the principle and implementation process of amplitude direction-finding technology. The paper had analysis and design of various parts of direction-finding units circuit. The first part was direction-finding receiver, including annular antenna, low-noise amplifier and FM receiver front-end. Low noise amplifier was the first-class active circuit in RF system, it had an important impact on system performance. The design features and performance indicators of low-noise amplifier ware introduced, on this basis we design the circuits. The superheterodyne structure was used in FM receiver. RF signals ware reduced to audio signal in second mixer. This paper introduced the implementation of the receiving demodulation circuit. The high stability local oscillator in mixer was generated in phase-locked frequency synthesizer, the loop filter, voltage-controlled oscillator circuit modules ware designed after explaining the principle of phase-locked loop.The second part was transmitter module, including the FM transmitter and power amplifier. First, the principle of single-point FM digital phase-locked transmitter ware introduced. Phase-locked FM circuit ware designed on the bias of phase-locked frequency synthesizer circuit. The paper also had analysis of some key indicators of the power amplifier, designed power amplifier circuit. Finally this paper debugged the amplifier in order to achieve optimal effect.The system has been successfully developed, and the test results fully met the requirements of technical indicators, it can achieve accurate direction finding and reliable communication, it can be widely used in airborne assembling and other civilian areas.