The Design And Implementation Of Multi-audio Shortwave Channel Simulator

With the emergence of wireless communication system nowadays, shortwave communication is always a main technology in interstate long-distance communication. At the later stage of the development of shortwave communication systems, the test procedure always faces the obstacles of the problems caused by the time-variation and unpredictability of shortwave channels, which dramatically delays development procedure. However, if the test of the system were done in the laboratory conditions with the help of the simulated shortwave channel, the research and development period of the system should be decreased largely.This thesis investigates the characteristics of multi-audio shortwave channel and related topics, designs a solution for simulating the multi-audio shortwave channel. Especially, considering the scheduling of multiple audio inputs, this thesis provides an IPC (Industrial Personal Computer) design with multiple sound cards. In order to reduce the complexity in following system test, and shorten the development life cycle, this work provides detailed implementation, and validates the feasibility.In this project, we propose the design of IPC with multiple sound cards, as well as three conditions that affect the multi-audio scheduling strategy. Then we design and implement the multi-sound-card IPC that can recognize multiple sound cards and schedule them efficiently.This thesis investigates several widely used shortwave channel models respectively, such as Watterson, Hoffmeyer, Parallel sub-band model, etc. We implement the shortwave simulator based on Watterson model, and achieve the goal of simulating the shortwave channel with multiple audio inputs.At last, we conduct detailed tests for the multi-sound-card IPC and shortwave channel simulator. A mount of test data validates various system modules. And we also test the system integrity, verifying the validity in system level.