Digital Signal Processing Reference
In-Depth Information
CHAPTER 1
Introduction to Signal Integrity
1.1
What Is Signal Integrity?
Signal integrity is the analysis, design, and validation of the interconnect necessary
for successful transmission of digital signals.
To do this, signal integrity (SI) engineering borrows ideas and practices from
many branches of electrical engineering. To those not having a background in ana-
log or radio frequency electronics, this diversity can make SI seem mysterious,
sometimes inconsistent, and occasionally difficult to understand. Logic designers
accustomed to working with binary logic can find the apparently imprecise, analog
nature of SI particularly frustrating.
Although knowledge in RF and analog electronics is helpful, modern SI CAD
allows nearly anyone to create SI simulations and make predictions about circuit
operation. However, as Henry Petroski points out [1], in general CAD software
vendors do not always advertise or may not fully understand the limitations of
their products. When expertly used, CAD is powerful, but its misuse can have dire
consequences.
The SI engineer and technical manager working with pulse data transmission
can avoid pitfalls like this by understanding the fundamental ideas described in this
topic.
1.2 The Importance of Signal Integrity: The First Transatlantic
Telegraph Cable
Managers and engineers not having a fundamental understanding of the technical
principles governing a project are more likely to make serious technical mistakes,
especially when pushing the state of the art. Perhaps the first time this became ap-
parent with regards to a significant high-speed signaling project occurred on August
16, 1858. That was when Great Britain's Queen Victoria sent a welcoming message
to U.S. President Buchanan over the first successfully laid transatlantic telegraph
cable [2-4]. This 3,800-km (about 2,400-mile) length of submarine cable connected
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