Intel 2920 Design Handbook page 8

CHAPTER 1
INTRODUCTION AND TERMINOLOGY
1.0 INTRODUCTION AND
TERMINOLOGY
This handbook provides the background review and
design examples that will help the reader to understand
analog signal processing applications using INTEL's
digital signal processing system, the 2920. The 2920 uses
digital sampled data techniques to implement con-
tinuous analog functions. In another words, analog
signal processing can now be performed with digital
signal processing techniques using the 2920.
Before looking at digital signal processing, it is useful to
clarify the distinctions between signal processing and
digital processing. Signal processing deals with con-
tinuous analog waveforms, whereas digital processing
operates on data that are represented in a digital form.
Digital signill processing would then be the operation on
digital representation of continuous signals.
Digital signal processing, in the most general sense,
means creating, altering, or detecting continuous
signals, using digital rather than analog or electro-
mechanical implementations. Furthermore, signal pro-
cessing can be distinguished from data processing in
that the former implies that real-time processing is
needed. Data processing, however, implies the
manipulation of data (which mayor may not represent
an action occurring presently) in a batch or off-line
manner, where the need for the result is not a function
of real-time.
Most digital microprocessors are designed for data pro-
cessing, not for high-speed complex signal processing.
The industry-standard 8080/8085 microprocessor sys-
tem can operate as a signal processor at frequencies to
only a few hundred hertz, and will require mUltiple
chips with a separate analog/digital conversion system
and I/O circuitry.
By contrast, general signal processing frequencies are in
the kilohertz range (thousands of cycles per second).
Many signals, such as speech, heartbeat, and seismic
waveforms are complex, and in many cases, multiple
signals must be processed in parallel. Because of dif-
ferent requirements for signal processing, a general pur-
pose microprocessor is not well suited for signal pro-
cessing applications. A different processor architecture
is required to implement signal processing algorithms.
1-1
1.1 The 2920 Signal Processor
The 2920 Signal Processor is a single chip microcom-
puter designed especially to process real-time analog
signals. The 2920 has on-board program memory,
scratchpad memory, D/ A circuitry, A/D circuitry,
digital processor, and I/O circuitry. It is more than a
single device, but is a complete digital sampled data
system. The architecture and instruction set was
developed to perform precise, high speed signal process-
ing. The processor executes its programs at typically
13,000 times a second when used with a 10 MHz clock
and full program memory. Each execution
(1
pass of the
2920 program memory) can process up to four input
signals and up to eight analog output signals. The pro-
cessing speed allows signals with bandwidths to 5
kilohertz to be processed; shorter programs permit
higher bandwidth. Its capabilities in signal processing
are diverse and powerful, and include an extremely
broad range of applications.
Some of the signal processing functions the 2920 can
implement are shown in Table 1-1. It is important to
note that these are fundamental building block func-
tions which corresponds to functional blocks in an
application block diagram. These are some of the
building blocks that can be linked together to implement
complex applications. Table 1-2 shows some of the
possible application areas for the 2920 Signal Processor.
The 2920 Signal Processor can implement any of the
listed functions under program control. Many functions
can be realized on the same chip. Interleaving multiple
inputs or outputs allows for several independent circuits
or a single highly complex one to be implemented. Even
higher complexity can be achieved by cascading 2920s.
If increased speeds are desirable, several 2920s can be
used in serial or parallel to achieve this. In most cases,
complete signal processing applications are imple-
mented on a single device.
The 2920 Signal Processor is only part of the solution.
Since a large part of the cost in producing a product is
the development time needed to design, test, and inte-
grate the new circuit into the final product, the 2920
support package has been developed. It provides the
software and hardware necessary to take a design from
concept to implementation on the 2920 Signal Pro-
cessor. This system combines a standard INTEL Intellec
Series II microcomputer development system with the
signal processing support package (SPS-20) to provide a
powerful set of hardware and software support tools.
This is described in Chapter 9.