Design And Implementation Of Miniature HF Channel Simulator

HF wave channel is a time-varying with complex characteristics,including multipath effect,Doppler effect.At the same time,it also contains a variety of noises form natural conditions and human operations.The field measurement of HF wave communication equipment is high in cost and long in period,it is difficult to guarantee the same text conditions.However,the efficient HF wave channel simulator can configure the channel scene,facilitate the repeated evaluation of the effectiveness of equipment functions under the same channel environment,and accelerate the launch of the communication system.At present,the function of HF wave channel simulator produced in China is relatively single,mainly for a single frequency band of radio.In the process of multi-frequency and multi-station channel simulation cannot meet the requirement.In foreign countries,the production of HF wave channel simulators is huge consumption and take up a large space.The main channel simulator is mainly aimed at the ground mobile communication,such as ROHED&SCHWARZ and SPIRENT and so on.The hardware design scheme of channel simulator and the realization method of key steps are given,and miniaturized HF wave channel simulator is designed,in this thesis.This channel simulator can support broadband and high dynamic signal input,and can realize HF wave channel simulation in normal state,at the same time,channel simulation of customized parameter input can also be realized.Users can configure required channel parameters for channel simulation and communication test under the requirements of actual channel simulation.Firstly,characteristics of the HF wave propagation and structure of the ionosphere are introduced in the thesis.The characteristics of HF wave propagation are analyzed from the aspects of multipath time delay,Doppler shifts,Doppler spread,and large-scale fading.Secondly,Watterson channel model and ITS channel model are introduced.Based on ITS channel model,calculation methods of relevant parameters of the model are derived.The key parts of the thesis,such as multipath time delay,Doppler shift,Doppler spread and large-scale fading,are also presented.Finally,the design scheme of the hardware and software of the HF wave channel simulator and the workflow are presented.The implementation principle and method of the key technologies are emphatically described.At the end of this thesis,the channel simulator is tested,and the result meet the requirements of the design.Compared with domestic research status and product indicators,the design has obtained the following indicators: the path delay range of 0-20 ms are accurate to 0.2?s;Doppler shift up to 1000 Hz and doppler spread up to 500Hz;achieve 0-30 MHz RF input;achieve 20-20 cm miniaturized hardware design.There are 56 figures,19 tables and 65 references in this thesis...