内蒙古科技大学电子信息专业英语翻译

Unit3

27-2In the binary system of representation the base is 2, and only two numerals 0 and 1 are required to represent a number. The numerals 0 and 1 have the same meaning as in the decimal system, but a different interpretation is placed on the position occupied by a digit. In the binary system the individual digits represent the coefficients of powers of two rather than ten as in the decimal system. For example, the decimal number 19 is written in the binary representation as

10011 since

10011=1×24+0×23+0×22+1×21+1×20=16+0+0+2+1=19

A short list of equivalent numbers in decimal and binary notation is given in Table 3.2.

二进制示数系统中的基数是二，且只有0和1两个数被用以示数。0和1在这里与在十进制中具有一样的意义，但每个数位表示的不一样。二进制系统中每个数字表示二的幂系数，而十进制中表示十的幂系数。例如，十进制数19在二进制中表示为10011因为

10011=1×24+0×23+0×22+1×21+1×20=16+0+0+2+1=19

二进制和十进制数相等数字见表3.2.

27-3A general method for converting from a decimal to a binary number is indicated in Table 3.3. The procedure is the following. Place the decimal number (in this illustration, 19) on the extreme right. Next divide by 2 and place the quotient (9) to the left and indicate the remainder (1) directly below it. Repeat this process (for the next column 9÷2 =4 and a remainder of 1) until a quotient of 0 is obtained. The array of 1’s and 0’s in the second row is the binary representation

of the origin decimal number. In this example, decimal 19=10011 binary.

十进制转换成二进制的一般方法如图3.3。过程如下：把十进制数（图中的19）放在最右端，接下来除以2，把商（9）放在左边并直接在其下方标明余数（1）。重复这个步骤（下一列为9÷2=4余1），直到商为0截止。第二行中的1和0就是原始十进制数的二进制表示。此例中，十进制19=二进制10011.

28-1A binary digit (a 1 or a 0) is called a bit. A group of bits that has the same significance is called a byte, word, or code. For example, to represent the 10 numerals (0, 1, 2, …, 9) and the 26 letters of the English alphabet would require 36 different combinations of 1’s and 0’s. Since 25<36<26, then a minimum of 6 bits per bite are required in order to accommodate all the alphanumeric characters. In this sense a bite is sometimes referred to as a character and a group

of one or more characters as a word.

一位二进制数（一个1或0)叫做比特。一组具有相同意义的比特叫做字节，词，或代码。例如，表示10个数字（0,1,2，...9）和26个英文字母要用到36种不同的1和0的组合。因为25<36<26，那么表示所有这些字母数字字符组最少需要6比特每字节。这种情况下一字节有时候被称为一个字符和一个或多个字符组成的字符串。

29-1The parameters of a physical device (for example, VCE·sat of a transistor) are not identical from sample to sample, and they also vary with temperature. Furthermore, ripple or voltage spikes may exist in the power supply or ground leads, and other sources of unwanted signals, called noise, may be present in the circuit. For these reasons the digital levels are not specified precisely, but as indicated by the shaded region in Figure 3.6, each state is defined by a voltage range about a designated level, such as 4±1 V and 0.2±0.2 V.

每个实体器件样本的参数(如晶体管的VCE·sat )是不完全相同的，它们还会随温度变化。而且，电源或地线可能存在电压脉动或电压峰值，其他干扰信号——噪声也可能出现在电路