简要-进制辅助.pptVIP

* * * 数字的革命 The Digital Revolution Please discontinue use of cell phone and turn off ringer The Digital Revolution Digital Camera Digital Video (DVD) Digital PCS Cell Phone Digital Convergence The Digital Divide DIGITAL TV DIGITAL DIGITAL THEATERS DIGITAL RADIO DIGITAL DIGITAL DIGITAL DIGITAL DIGITAL DIGITAL What’s all this fuss about digital?! 二进制位(比特) bit 计算机中用1和0表示、存储、操纵数据。 在电子设备中，位（bit）是最小的数据单元 位在电子设备中不是真正的“1”和”0”,而是设备的两个状态。 位可以是电容中电压的改变和未改变的两个状态。 位可以是磁盘表面磁性颗粒磁场的改变和未改变的两个状态。 位可以是光盘表面是否有烧蚀的微小坑点的两种状态。 …… The bit How can a bit (an on-off switch) represent useful data and information? Information can be assigned to the two states of the bit: On = Off = The bit 1 and 0 are typically used to describe the state of a bit, but you could use anything; black/white, true/false, male/female, etc. 00 = 01 = 10 = 11 = How many units of information could be represented with 2 bits? The bit 000 = 001 = 010 = 011 = How many units of information could be stored using 3 bits? 100 = 101 = 110 = 111 = The bit 增加比特（位）数，可以更加细腻地利用数字化来描绘信息。 The bit # of Bits Units of Info 1 2 2 4 3 8 4 ? 4 bits 能够表示多少个信息单元? The bit # of Bits Units of Info 1 2 2 4 3 8 4 16 5 32 6 64 7 128 8 256 General Rule: 2bits = units of info 8 bits = a Byte The Bit Bytes can represent any collection of items using a “look-up table” approach ASCII is used to represent characters 位和字节 bit Bytes Some of the ASCII characters ASCII Code Char Character Name [ Left Bracket \ Backward Slash ] Right Bracket ^ Caret _ Underscore ` Back Quote a Lower-case A b Lower-case B c Lower-case C d Lower-case D e Lower-case E f Lower-case F g Lower-case G h Lower-case H The binary number system uses only two values, 0 and 1, and is used by computers and digital devices to represent and process data. bit Bytes Decimal 十进制 Binary 二进制 239bit Bytes 点击运行Binary Counter 2