Radio transmission system

This chapter deals with the various aspects of systems design that were considered to be the province of radio engineering. With the introduction of digital communications, several new themes have been introduced, such as signal coding and new modulation techniques. In addition, digital technology has caused significant changes to radio architecture due to factors such as shielding and power consumption. The explosion of commercial radiocommunications has also made possible the mass production of high-performance radio chip sets. Several books are available on specific aspects of digital radio such as continuous-phase modulation and forward-error coding, some of which are referred to later for further study. Our purpose is to give a general description of radio transmission systems, with more detail on specific areas relevant to spread spectrum communications. Direct-sequence spread spectrum systems will be given special attention.