《电子技术数字基础 Digital Fundamentals》双语PPT-第01章 Digital Concepts

1、11 Introductory Digital Concepts2Contentsw Digital and Analog Quantitiesw Binary Digits, Logic Levels and Digital Waveformsw Basic Logic Operations (be discussed together with chapter 3)31-1-1 Digital and Analog Quantities（数字量和模拟量）w Electronic circuits can be divided into two broad categories, digit

2、al and analog.w We are discussing digital electronics(数字电子学） in this term and we will discuss analog electronics （模拟电子学）next term.41-1-1 Digital and Analog Quantities An analog quantity (模拟量模拟量)is one having continuous (连续的连续的) values.51-1-1 Digital and Analog QuantitiesA digital quantity (数字量数字量) i

3、s one having a discrete (离散的离散的 )(discontinuous) set of values.High Level（高电平）（高电平）Low Level（低电平）（低电平）61-1-1 Digital and Analog Quantities Many quantities are analog in nature; that is, they are continuous quantities. Physical quantities such as temperature (温度温度), pressure (压力压力), time (时间时间), velo

4、city(速度速度), and sound (声音声音) are examples of analog quantities.71-1-2 Analog SystemsAn analog electronic system: - a public address systemAmplifier81-1-3 Digital SystemsNow most of modern electronic devices and systems are digital system. 91-1-3 Digital Systems101-1-4 Analog and Digital SystemsThe C

5、D player111-1-5 ADC and DACw Music in digital form is stored on the compact disk.w DAC: digital-to-analog converterw Analog signal is got.w Another procedure: ADC analog-to-digital converter.121-1-6 The Digital Advantagew Can be processed and transmitted more efficiently and reliably .w Easy to be s

6、tored, and can be stored more compactly and so on.w Cant be affected by noise (unwanted voltage fluctuations).131-2 Binary Digits, Logic Levels, and Digital Waveforms w Digital electronics : 2 possible states.w 2 states: (1) 2 different voltage levels: HIGH and LOW. (2) switch: open and close. (3) l

7、amp: turned on and off. (4) 2 opposite states.141-2-1 Binary Digitsw The two-state number system is called binary(二进制）二进制）, and its two digits are 0 and 1.w Positive logic (common) (正逻正逻辑）辑）: HIGH=1 and LOW=0.w Negative logic (负逻辑）负逻辑） (less common): HIGH=0 and LOW=1Logic 0Logic 1False TrueOffOnLowH

8、ighNoYesOpen switchClosed switch151-2-2 Logic Levels ()w The voltages used to represent a 1 and a 0 are called logic levels.w The figure illustrates the general range of LOWs and HIGHs for a digital circuit.w TTL: HIGH 2-5V and LOW 0-0.8V.Logic level for typical CMOS logic circuits161-2-3 Digital Waveforms (数字波形）w The pulse: rising (leading) edge (上升沿）上升沿）and falling (trailing) edge (下降沿）下降沿）.w Pulse width : (脉宽）脉宽） the duration of