数字设计——原理与实践 Welcome to the word of digital design.Perhaps you're a com-puter science student who knows all about computer software and programming,but you're still trying out how all that fancy hardware enineering student who already knowa some-thing about analog electronics and circuit design,but you wouldn't know a bit if it bit you.No matter.Starting from a fairly basic level,this book will show to design digital circuits and subsystems.

1.1 About Digital Design

Some people call it “logic design.” That’s OK, but ultimately the goal of

design is to build systems. To that end, we’ll cover a whole lot more in this

text than just logic equations and theorems.

This book claims to be about principles and practices. Most of the principles

that we present will continue to be important years from now;