dsp architecture
Sophisticated signal processing functions can be realized using digital techniques – numerous important signal processing techniques are difficult or impossible to implement using analog (continuous time) methods. Their reprogrammability is a strong advantage over conventional analog systems. Furthermore digital systems are inherently more reliable, more compact, and less sensitive to environmental conditions and component aging than analog systems. The digital approach allows the possibility of time-sharing (or multiplexing) a given DSP microprocessor among a number of different signal processing functions.
http://lsiwww.epfl.ch/LSI2001/teaching/webcourse/ch12/DSParch.htm