Publisher Summary Radio technology provides a means to send information without wires and offers the flexibility that is becoming increasingly important in today's highly mobile world. The performance of radio sets is being improved all the time and new facilities are being introduced. The introduction of wideband frequency modulation (FM) represented a major improvement. Stereo facilities are now taken for granted and other enhancements such as Radio Data System (RDS) are available in many countries today. Beyond this, digital radio or digital audio broadcasting has started. This brings true CD quality to radio broadcasts as well as allowing data to be broadcast at the same time. Cellular telecommunications is another technology that has been made possible by the development of radio. The first generation systems used analogue technology. The second generation systems use digital technology, and now the third generation (3G) systems offers high data rate capabilities that enables them to provide far more facilities and flexibility.