An R.F. data link

Abstract

As an electrical engineering student who would be ultimately working in the telecommunications field, I felt the urgent need to acquaint myself with transmission and reception techniques and problems. Since all modern and future-envisaged systems work on data transfer, I thought it best to deal with computer digital data transmission/reception. The area which interested me most was the low powered HF radio links and of the various methods that are used for the transmission of digital data over such a channel. In my project, I tackled the above considerations mainly from the communications design aspects and my aim was to design, construct and test an effective digital transmission/reception system. Small range wireless communications between computers is currently being studied in great depth by companies like Motorola, Agilis and O'Neill who are introducing wireless LANs in the market using a carrier frequency of 18 GHz transmitting 9.6k bit/s of information to 32 users with a power rating of 20mW over a range of 35m. Obviously, the aim of my project was not to reach such level but to get acquainted with basic CCITT and other set regulations and standards as regards ~F data transmission. Although radio-based communications between computers within an office or small building will not challenge conventional wired networks, they can be potential problem solvers where easy handling of data is required. The recent introduction of a diary-sized personal computer, further aids in implementing such a system. [...]