不同类型的无线通信媒体
我们生活在一个世界里，无论他们距离多远，我们都可以在几秒钟内与朋友建立联系。但这在早期是不可能的。我们都听说过并读到过早期的沟通非常困难，因为发送一封信需要很多天，有时甚至几个月。今天不是一个例子，我们有不同类型的媒体可以非常快速地传递我们的信息。在本文中，我们将了解传输介质和无线通信之后。现在，什么是传输介质？基本上，它将信号或消息从一台计算机传输到另一台计算机。传输介质又分为两种：有线或引导式传输介质（例如：双绞线、以太网电缆、同轴电缆、光纤）和其他无线或非引导式传输介质（例如：红外线、无线电链路、微波链路） ，卫星链接，蓝牙，WIFI）。
在这篇文章中，我们更关注的是无线通信。那么，让我们开始了解无线通信。
无线通信
无线通信也称为无引导媒体或无界传输媒体。在这种模式下，电磁信号的传输不需要物理介质。在无线通信中，我们可以通过空气、水或真空即红外线、无线电波、微波来传递我们的信息。因此，我们不必担心传输消息的电缆或任何材料，因为我们可以在没有介质的情况下发送消息。
无线通信有优点也有缺点，如果我们谈论安全性，它的安全性较低。
特征
- 传输不需要物理介质。
- 它可以通过空气、水或真空传输信号。
- 它可以旅行很远的距离，但也不太安全。
让我们讨论它的一些类型：-
红外线的
红外线用于电视遥控器、手机、个人电脑等短距离通信。在科学中，红外线是人眼不可见的光谱的一部分。红外线的局限性在于不能穿透任何障碍物，只能用于近距离。此外，红外用于夜视摄像机，因为它具有热特性。红外线频率范围 300GHz – 400THz
用途：
正如我们已经讨论过的，它们用于电视遥控器、鼠标等 PC 设备和键盘。
优缺点：
如果我们谈论红外线的优点部分，那么我们可以说红外线是安全的无线通信介质之一，因为它用于短距离。此外，与其他无线介质不同，红外线相当便宜，这也是它在许多电子设备中使用的一些原因。
现在，让我们谈谈红外波的劣势部分，因此它们只能用于短距离通信。此外，它们不能穿透任何障碍物，如墙壁或任何建筑物。
无线电波
所以我们已经看到了红外波的局限性，所以这里有另一种无线通信，它没有像红外这样的局限性。我们在这里讨论无线电波。可以传播很远的距离并且可以穿透任何墙壁（全向，这些波可以向各个方向移动）。这些很容易生成并且可以穿透建筑物。无线电波的要求是天线，一个可以发送信息的发送天线，另一个是接收天线。无线电波的频率范围：3KHz – 1GHz。此外，频率为 300KHz-30MHz 的无线电波可以长距离传播。此外，它们容易受到干扰，这意味着它们可以穿透任何墙壁。
用途：
无线电波用于 AM 和 FM 收音机以及无绳电话。此外，一些私人和政府组织保留某些无线电频率用于直接通信。
优缺点：
无线电波具有一些优点，例如可以在各个方向长距离传播，可以穿越任何障碍物，并且由于它们是无线通信介质，因此无需挖掘和铺设电线。但是，是的，无线电波也有一些缺点，例如无线电波在恶劣的天气条件下无效，而且它们的安全性较低，因为它们可以传播很远的距离。
微波炉
微波是一种视线传输，这意味着发送和接收的天线都应该正确对齐。此外，信号覆盖的距离与天线的高度成正比。微波的频率范围在 1GHz – 300GHz 之间。基本上，我们在手机通讯和电视分配中使用了微波。
与无线电波不同，它们是单向的，因为它们只能在一个方向上移动，因此它用于点对点通信或单播通信，如雷达和卫星。
用途：
微波用于手机通讯和电视分配。
优缺点：
如果我们谈论微波的优点，那么我们说它是一种非常快速的通信方式，可以同时承载 25000 个语音通道。此外，它是一种无线通信介质，因此无需挖掘和铺设电线。
现在微波炉的缺点是第一笔费用，它们的安装和维护都非常昂贵。这变成了一种非常昂贵的通信方式。此外，微波在恶劣的天气条件下也不是很有效。
红外线、无线电波、微波的比较
| S.no | Infrared | Radio Waves | Microwaves |
|---|---|---|---|
| 1 | Infrared is used for short-range communication like TV remotes, mobile phones, personal computers, etc. In science, the Infrared is part of a spectrum that is not visible to the human eye | Radio waves are the type of wireless communication that can travel large distances as well as can penetrate any wall | Microwaves are a line of sight transmission, meaning both the antennas sending and receiving should be properly aligned. |
| 2 | The frequency range of infrared rays 300GHz – 400THz | The frequency range of radio waves:3KHz – 1GHz. | Microwaves have a frequency Range between 1GHz – 300GHz. |
| 3 | The limitation of infrared rays is that they cannot penetrate any obstacles and can only use for short-range. Also, Infrared is used in night vision cameras as it has thermal properties. The frequency range of infrared rays 300GHz – 400THz | It can travel large distances as well as can penetrate any wall ( Omni-directional, | They are unidirectional, as they can move in only one direction, and therefore it is used in point-to-point communication or unicast communication such as radar and satellite. |
| 4 | Infrared is one of the secure wireless communication mediums as it is used for short-range. Also, unlike other wireless mediums, infrared is quite inexpensive, and this is some reason it is used in many electronic devices. | If we talk about the advantages of microwaves then we say that it is a very fast way of communication, that can carry 25000 voice channels at the same time. Also, it is a wireless communication medium so there is no need of digging and spreading wires. | Advantages of microwaves then we say that it is a very fast way of communication, that can carry 25000 voice channels at the same time. Also, it is a wireless communication medium so there is no need of digging and spreading wires. |
| 5 | Infrared waves are used in TV remotes, mobile phones, personal computers | Radio waves are used in AM and FM radios, and cordless phones. | Microwaves are used in mobile phones communication and television distribution. |
示例问题
问题1：写一个关于微波的简短笔记。
解决方案
Microwaves are a line of sight transmission, meaning both the antennas sending and receiving should be properly aligned. Also, the distance covered by the signal is directly proportional to the height of the antenna. Microwaves have a frequency Range between 1GHz – 300GHz. Basically, we used Microwaves in mobile phones communication and television distribution.
Unlike radio waves, they are unidirectional, as they can move in only one direction, and therefore it is used in point-to-point communication or unicast communication such as radar and satellite.
问题2：无线通信是什么意思。举个例子。
解决方案
It is also referred to as Unguided Media or Unbounded transmission media. No physical medium is required for the transmission of electromagnetic signals. In wireless communication we can transfer our message through the air, water or vacuum i.e. Infrared, Radio wave, Microwave wave. So, we don’t worry about the cables or any material to transfer messages, as we can send out a message without and medium.
问题3：红外线的频率范围是无线电波、微波。
解决方案
The frequency range of Infrared, Radio and Microwaves are 300GHz – 400THz,3000Hz – 1GHz, 3000Hz – 1GHz respectively.
问题4：写出无线电波的一些优点和缺点。
解决方案：
Radio waves have some advantages like they can travel long distances in all directions and can pass through any obstacles, and since they are wireless communication mediums so there is no need of digging and spreading wires. But, yes radio waves have some disadvantages too like radio waves are not effective in bad weather conditions, and they are less secure as they can travel large distances.
问题5：写出无线通信的一些特性。
解决方案
Following are the features of wireless communication:-
- No physical medium is required for transmission.
- It can carry signals through air, water, or vacuum.
- It can travel large distances but it is also less secure.
问题 6：写出红外波的局限性。
解决方案：
Infrared can only be used in short-range communication. Also, they cannot penetrate any obstacles like walls or any building.