Overview

In home stereo, conventional wisdom suggests digital signal processing has taken over more and more of the audio signal-processing chain. But has it? If you lift the lid on some of the most dazzling audio equipment shown at the Consumer Electronics Show in Las Vegas this week, you will find a startling amount of analog circuitry.

Digital signal processing has proven its value in DVD playback, MPEG video decoding and decoding "5.1" audio channels from a 192-kbit/second Dolby Digital data stream. But beyond that, what does the DSP really do? Even where the sound chain is decidedly digital-as with pulse-width-modulated Class D amplifiers-the signal-processing expertise is decidedly analog. But it is with DVD players-especially the new-generation models with recording capability-that DSP returns with a vengeance.

In this week's In Focus section, experts take a look at the trade-offs between digital and analog audio system design.