Data Transmission | 数据传输

📚 Data Transmission | 数据传输

Data transmission is the transfer of information from one place to another. It is the foundation of mobile phone calls, internet browsing, television broadcasting, remote controls, and scientific data logging. In IGCSE Science, we study how signals are generated, sent through cables or electromagnetic waves, and recovered at the receiver.

数据传输是指将信息从一个地方传递到另一个地方。它是移动电话通话、互联网浏览、电视广播、遥控器和科学数据记录的基础。在 IGCSE 科学课程中，我们学习信号是如何产生、通过电缆或电磁波发送，并在接收端被还原的。

1. What Is Data Transmission? | 什么是数据传输？

Data transmission means sending encoded information from a transmitter to a receiver. The information can be voice, text, images, sensor readings, or video. A basic system has three stages: input/encoding, transmission through a medium, and output/decoding.

数据传输意味着将编码后的信息从发送端传递到接收端。信息可以是声音、文字、图像、传感器读数或视频。一个基本系统包括三个阶段：输入/编码、通过介质传输以及输出/解码。

Examples in everyday life include a smartphone sending a photo over Wi-Fi, a television receiving broadcast signals, and a heart-rate monitor sending pulses to a display. In each case, the original information is converted into a signal that can travel physically.

日常生活中的例子包括智能手机通过 Wi-Fi 发送照片、电视接收广播信号，以及心率监测器将脉搏信号发送到显示器。在每种情况下，原始信息都会被转换成能够物理传播的信号。

A transmitter encodes the information into a suitable signal. The medium carries the signal from one location to another. The receiver then decodes the signal to recover the original message.

发射端将信息编码为合适的信号。介质将信号从一个位置传送到另一个位置。然后接收端对信号进行解码，以恢复原始信息。

2. Analogue and Digital Signals | 模拟信号与数字信号

An analogue signal varies continuously in amplitude or frequency. Sound waves from a microphone, the voltage from a thermocouple, and the changing brightness of a scene are naturally analogue. A graph of an analogue voltage against time is a smooth curve.

模拟信号的振幅或频率是连续变化的。来自麦克风的声音波、热电偶的电压以及场景亮度的变化天然都是模拟量。模拟电压随时间变化的图像是一条平滑曲线。

A digital signal has only a small number of discrete levels, usually two levels called high and low. These two levels represent binary digits 1 and 0. Digital signals change in steps rather than smoothly.

数字信号只有少数几个离散电平，通常是两个电平，称为高电平和

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