20.15 电子信号
章节大纲
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Did you ever make a secret code by assigning each letter of the alphabet a unique symbol? The code shown above is believed to have been used by George Washington to send secret messages during the American Revolutionary War. A different type of code can be sent with electric current .
::您是否曾通过给字母字母中的每个字母指定一个独特的符号来制作过秘密代码? 上面显示的代码据信被乔治·华盛顿用于在美国革命战争期间发送秘密信息。 另一种代码可以用电流发送。Q: How do you think electric current can be used to encode messages?
::问题:你认为电流如何用于编码信息?A: The short answer is by changing the voltage in an electric circuit . Keep reading to learn more.
::A: 简短的答案是改变电路的电压。 继续阅读以学习更多 。Electronic Messages
::电子电文Electric devices, such as lights and household appliances, change electric current to other forms of . For example, an electric stove changes electric current to . Other common devices, such as mobile phones and computers, use electric current for another purpose: to encode information. A message encoded this way is called an electronic signal , and the use of electric current for this purpose is called electronics .
::电动设备,例如灯光和家用电器,将电流改变为其他形式的电流。例如,电炉将电流改变为电流。其他常用设备,例如移动电话和计算机,将电流用于另一个目的:编码信息。这种编码的信息称为电子信号,为此目的使用电流则称为电子。To encode a message with electric current, the voltage is changed rapidly, over and over again. Voltage is a difference in electric that is needed in order for electric current to flow. There are two different ways voltage can be changed, resulting in two different types of electronic signals, called analog signals and digital signals.
::为了用电流编码电文,电压会一次又一次地迅速改变。电压是电流流动所需要的电力差异。 电压可以改变两种不同的方式,导致两种不同的电子信号,即所谓的模拟信号和数字信号。Analog Signals
::模拟信号Analog signals consist of continuously changing voltage in an electric circuit. The Figure represents analog signals. These were the first electronic signals to be invented. They were used in early computers and other early . Analog signals are subject to distortion and noise, so they aren’t used as often anymore. They are used mainly in microphones and some mobile phones to encode sounds as electronic signals.
::模拟信号包括电路电压的不断变化。 图中代表了模拟信号。 这些是最早发明的电子信号。 这些信号被早期计算机和其他早期的计算机使用。 模拟信号受到扭曲和噪音的影响,因此不再经常使用。 它们主要用于麦克风和一些移动电话,将声音编码为电子信号。Digital Signals
::数字信号Today, most electronic signals are digital signals. Digital signals consist of rapid pulses of voltage that repeatedly switch the current off and on. The Figure represents digital signals. This type of signal encodes information as a string of 0’s (current off) and 1’s (current on). This is called a binary (“two-digit”) code. The majority of modern electronic devices, including computers and many mobile phones, encode data as digital signals. Compared with analog signals, digital signals are easier to transmit and more accurate.
::今天,大多数电子信号都是数字信号。数字信号由电压的快速脉冲组成,反复地将电流关闭和开关。图代表数字信号。这种信号将信息编码为0(当前关闭)和1(当前运行)的字符串。这被称为二进制(“两位数 ” ) 。 包括计算机和许多移动电话在内的大多数现代电子设备将数据编码为数字信号。与模拟信号相比,数字信号更容易传输,更准确。Watch this video to learn more about analogue and digital signals:
::观看这段影片以了解更多模拟和数字信号:Summary
::摘要-
A message encoded by changing the voltage of an electric current is called an electronic signal. The use of electric current for this purpose is known as electronics.
::通过改变电流电压编码的电文称为电子信号,为此目的使用电流称为电子。 -
Electronic signals may be analog or digital signals. Analog signals consist of continuously changing voltage in an electric circuit. Digital signals, which are the main type of signals used today, consist of rapid pulses of voltage that repeatedly switch the current off and on.
::模拟信号包括电路不断变化的电压,数字信号是今天使用的主要信号类型,由电压的快速脉冲组成,反复断开电流和开关。
Review
::回顾-
What is an electronic signal?
::什么是电子信号? -
Define electronics.
::界定电子产品。 -
Create a table comparing and contrasting analog and digital signals.
::创建一个比较和对比模拟和数字信号的表格。
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A message encoded by changing the voltage of an electric current is called an electronic signal. The use of electric current for this purpose is known as electronics.
