Dsp, Capitulo 1

CHAPTER

1

The Breadth and Depth of DSP

Digital Signal Processing is one of the most powerful technologies that will shape science and
engineering in the twenty-first century. Revolutionary changes have already been made in a b road
range of fields: communications, medical imaging, radar & sonar, high fidelity music
reproduction, and oil prospecting, to name just a few. Each of theseareas has developed a deep
DSP technology, with its own algorithms, mathematics, and specialized techniques. This
combination of breath and depth makes it impossible for any one individual to master all of the
DSP technology that has been developed. DSP education involves two tasks: learning general
concepts that apply to the field as a whole, and learning specialized techniques for yourparticular
area of interest. This chapter starts our journey into the world of Digital Signal Processing by
describing the dramatic effect that DSP has made in several diverse fields. The revolution has
begun.

The Roots of DSP
Digital Signal Processing is distinguished from other areas in computer science
by the unique type of data it uses: signals. In most cases, these signals
originate assensory data from the real world: seismic vibrations, visual images,
sound waves, etc. DSP is the mathematics, the algorithms, and the techniques
used to manipulate these signals after they have been converted into a digital
form. This includes a wide variety of goals, such as: enhancement of visual
images, recognition and generation of speech, compression of data for storage
and transmission,etc. Suppose we attach an analog-to-digital converter to a
computer and use it to acquire a chunk of real world data. DSP answers the
question: What next?
The roots of DSP are in the 1960s and 1970s when digital computers first
became available. Computers were expensive during this era, and DSP was
limited to only a few critical applications. Pioneering efforts were made in four
key areas:radar & sonar, where national security was at risk; oil exploration,
where large amounts of money could be made; space exploration, where the

1

2

The Scientist and Engineer's Guide to Digital Signal Processing

d ata are irreplaceable; and m edical imaging , where lives could be saved.
The personal computer revolution of the 1980s and 1990s caused DSP to
explode with new applications.Rather than being motivated by military and
government needs, DSP was suddenly driven by the commercial marketplace.
Anyone who thought they could make money in the rapidly expanding field was
suddenly a DSP vender. DSP reached the public in such products as: mobile
telephones, compact disc players, and electronic voice mail. Figure 1-1
illustrates a few of these varied applications.
Thistechnological revolution occurred from the top-down. In the early
1980s, DSP was taught as a graduate level course in electrical engineering.
A decade later, DSP had become a standard part of the u ndergraduate
curriculum. Today, DSP is a b asic skill needed by scientists and engineers

Space

Medical

-Diagnostic imaging (CT, MRI,
ultrasound, and others)
-Electrocardiogram analysis-Medical image storage/retrieval

Commercial

-Image and sound compression
for multimedia presentation
-Movie special effects
-Video conference calling

Telephone

-Voice and data compression
-Echo reduction
-Signal multiplexing
-Filtering

Military

-Radar
-Sonar
-Ordnance guidance
-Secure communication

Industrial

-Oil and mineral prospecting
-Process monitoring & control-Nondestructive testing
-CAD and design tools

Scientific

DSP

-Space photograph enhancement
-Data compression
-Intelligent sensory analysis by
remote space probes

-Earthquake recording & analysis
-Data acquisition
-Spectral analysis
-Simulation and modeling

FIGURE 1-1
DSP has revolutionized many areas in science and engineering. A
few of these diverse applications are...