The Application of Programmable DSPs in Mobile Communications

14

The Role of Programmable DSPs in Digital Radio

Trudy Stetzler and Gavin Ferris

14.1 Introduction

Existing AM and FM broadcasting have remained relatively unchanged since the 1960s when FM stereo transmission was introduced. Meanwhile, audio recording techniques have undergone tremendous change from traditional analog to high quality digital recording with the introduction of compact disc, and most recently MP3 compressed audio recording to permit music be transmitted via the Internet. Traditional analog broadcasts were originally designed for stationary receivers and suffer from degradation of the received signal when used in a mobile environment with weak signal strength and multipath. The listener typically experiences these deficiencies as pops and dropouts caused by selective fading, distortion of a weak signal caused by a strong interferer or multipath reflections, or bursts of noise caused by electrical interference.

The impact of digital technology on broadcast radio will be as significant as it was for cellular phones. Digital broadcasting offers the opportunity for the broadcaster to deliver a much higher quality signal to home, portable, and automotive receivers. The key features for a Digital Audio Broadcast (DAB) service are to provide near CD quality sound, high immunity to multipath and Doppler effects, spectrum efficiency, and low cost receivers. A digital transmission system also enables a new range of data services to complement the audio programming since it ...