Have you ever wondered how data is transferred over the air? The reason why its possible to download your favorite song on WiFi or send your loved ones a Whatsapp message yet they so far away? Well this is what we are going to discuss today. Its not so complicated after you understand the basic concepts that make this possible.
Before i can explain how data is transferred over the air you need to know what communication is. Communication can be defined as the imparting or exchanging of information by speaking, writing, or using some other medium. Imagine that 2 people A & B are standing on opposite sides of the road “A” is holding a torch and the other one “B” is waiting for a signal. Lets say they agree that if the torch is flashed twice it mean that person “B” can cross the road if not he/she should just stand there. There has been no physical contact but they have successfully communicated because “B” understands the message being sent.
In this scenario they used light to carry the information. Communication on radio works in a similar way and the carrier of the information are electromagnetic waves.
How data is transferred over the air
The important characteristics of a wave we need to know for now are the Amplitude, Phase, Period & its reciprocal Frequency. Radio is the transmission of signals by the modulation of electromagnetic waves.
- Amplitude is the maximum displacement of points on a wave, which you can think of as the degree or intensity of change.
Phase is a particular point in time on the cycle of a waveform, measured as an angle in degrees. A complete cycle is 360°.
- Period (denoted by ‘T’ ) is the time needed for one complete cycle of vibration to pass in a given point.
- Frequency is the inverse of the period (1/T).
Modulation enables the transfer of information on an electrical signal to a receiving device. The receiver then demodulates the signal to extract the information. Modulation has three different types and It’s achieved by altering the periodic waveform or the carrier. The types are Amplitude, Frequency and Phase modulation
If you change the amplitude as a function of the information you want to send, you’ve got Amplitude Modulation(AM). If you change the frequency to be a bit faster/slower according to what you want to send, you’ve got Frequency Modulation(FM). There are also other methods like Phase Modulation that are a bit more complicated. And some things use a combination of modulation techniques together, such as AM and PM.
Wrapping it up
As long as the sender and receiver both understand the code, you can transmit information. I do hope this will help you appreciate the Physics behind this concept. Now that you know how data is transferred over the air, do like our Facebook Page and follow me on Linked-in.