Digital signal processing (DSP) is used in a wide range of applications
such as speech, telephone, mobile radio, video, radar and sonar. The
sample rate requirements of these applications range from 10 KHz to 100
MHz. Real time implementation of these systems requires design of
hardware which can process signal samples as these are received from the
source, as opposed to storing them in buffers and processing them in
batch mode. Efficient implementation of real- time hardware for DSP
applications requires study of families of architectures and
implementation styles out of which an appropriate architecture can be
selected for a specified application. To this end, the digit-serial
implementation style is proposed as an appropriate design methodology
for cases where bit-serial systems cannot meet the sample rate
requirements, and bit-parallel systems require excessive hardware. The
number of bits processed in a clock cycle is referred to as the
digit-size. The hardware complexity and the achievable sample rate
increase with increase in the digit-size. As special cases, a digit-
serial system is reduced to bit-serial or bit-parallel when the
digit-size is selected to equal one or the word-length, respectively. A
family of implementations can be obtained by changing the digit-size
parameter, thus permitting an optimal trade-off between throughput and
size. Because of their structured architecture, digit-serial designs
lend themselves to automatic compilation from algorithmic descriptions.
An implementation of this design methodology, the Parsifal silicon
compiler was developed at the General Electric Corporate Research and
Development laboratory.