4. How does wireless work?

 

4. How does wireless work?



12.12.2018
Topic Progress:

How does wireless work – Transcript:

Wireless History

Wireless communication has developed at a high rate. Wireless however is not a new invention.

  • In 1864, Maxwell proved the existence of electromagnetic waves
  • In 1887, Hertz sent and received wireless waves
  • In 1895, Marconi sent radio signals over more than a mile.
  • In 1920, there was a first commercial radio broadcast
  • In 1930, BBC began television experiments.
  • In 1974, FCC allocates 40 MHz for cellular telephony
  • In 1982, European GSM was established.

This is where we can say that modern wireless communication began.

Where is Wireless

Where can we find wireless now? It is used mostly for broadcasting or communication in

  • Radio,
  • Television,
  • Satellites,
  • Wi-Fi,
  • Mobile networks: 3G, 4G or 5G,

Wireless can be used not only to transmit the data. For example, radars are based on waves.

Where does wireless start

Where does exactly wireless start? First, we need a device, called transmitter, which has an antenna.

Inside transmitter, there is an oscillator, that is connected to the antenna.

Oscillator creates signal that propagates through the wires to the antenna.

Antenna is a conductor, so signal propagates further towards the end of antenna.

  • Signal generated by the oscillator is generated continuously and antenna radiates that signal into the air as an electromagnetic wave. Signal in the antenna is an electric current, while propagated signal is wave.

Spectrum Fragmentation

Depending on how fast signal is changing, antenna radiates signal of different frequencies. These frequencies can be used for different purposes like:

  • Radionavigation
  • Maritime mobile
  • Radiolocation
  • Broadcasting (FM radio)
  • Mobile communication
  • ISM band, where everyone can transmit
  • Satellite
  • Space research

Radio System Altogether

In order to communicate using wireless we need more than just transmitter with an antenna.

Signal radiated by the antenna goes into the channel which transports the information and finally reaches the receiver. In order to capture the data, a receiving antenna is required, which intercepts the radio waves and converts them back to the current.


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