Chapter2 Number systems and Codes资料文件与下载

Chapter2 Number systems and Codes

本章导读

二进制数字系统是计算机和数字电子学的基础。在本章中，介绍二进制数字系统以及它与其他数字系统的关系，给出了十进制、十六进制和八进制及其其他进制。数字编码如二进制编码的十进制(BCD)，格雷码， ASCII，奇偶校验方法。

In the decimal number system each of the ten digits, 0 through 9, represents a certain quantity. As you know, the ten symbols (digits) do not limit you to expressing only ten different quantities because you use the various digits in appropriate positions within a number to indicate the magnitude of the quantity. You can express quantities up through nine before running out of digits; if you wish to express a quantity greater than nine, you use two or more digits, and the position of each digit within the number tells you the magnitude it represents.

The binary number system is another way to represent quantities. It is less complicated than the decimal system because the binary system has only two digits. The decimal system with its ten digits is a base-ten system; the binary system with its two digits is a base-two system.The two binary digits (bits) are 1 and 0. The position of a 1 or 0 in a binary number indicates its weight, or value within the number, just as the position of a decimal digit determines the value of that digit. The weights in a binary number are based on powers of two.

To learn to count in the binary system, first look at how you count in the decimal system. You start at zero and count up to nine before you run out of digits. You then start another digit position (to the left) and continue counting 10 through 99. At this point you have exhausted all two-digit combinations, so a third digit position is needed to count from 100 through 999.

本章要点

2-1 Decimal Numbers

2-2 Binary Numbers

2-3 Decimal-to-Binary Conversion

2-4 Binary Arithmetic

2-5 Complements of Binary Numbers

2-6 Hexadecimal Numbers

2-7 Octal Numbers

2-8 Binary Coded Decimal (BCD)