Digital signal processing techniques were first applied as no-realtime simulation of complex analog systems on a computer in order to experiment with choices of parameters and other design parameters. The development of faster computers changed the situation. DSP is now used as a replacement of analog systems in a large variety of applications. Integrated circuit technology has advanced to a state where complex digital systems can be implemented on a single chip. This led to the introduction of DSP in commercial products like home TV sets or CD-players. The purpose of this paper is to present a car radio audio system based upon a two DSP-chip-set, developed by ITT-INTERMETALL.
The first chip, called PPUC (Preprocessor Unit) is doing source switching. A/D and D/A conversion, stereo decoding. ARI decoding and analog volume control. The second is a masc progammed version of a general purpose signalprocessor. This IC realizes audio features like stereo matrix, deemphasis, tone control, ambience enhancement as well as non audio functions like PLL, noise reduction systems. ARI etc. Both chips can be controlled by any microcomputer by means of a slow serial bus.
First he architecture of the signal processor (UDPC) as well as the instruction set will be shown. Then the system configuration and the PPUC are presented. A final discussion gives an conclusion and an oulook to future digtial car radio activities