1. Wireless technology

2. Wireless technology Electromagnetic waves
Transmission of radio-waves and microwaves
Transmission of infrared waves
Radio wave-based networking

3. Electromagnetic waves
Transmit data across the atmosphere.
Are categorized according to frequency ranges.
Frequency ranges are based on repeating patterns of a waveform.
One complete waveform is called a cycle.
Frequency is the number of times a cycle occurs in one second.
Include:
Radio waves
Microwaves
Infrared waves
Crest
One cycle
Trough
Electromagnetic spectrum
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Wavelength

4. Wavelength
The length of a wave is the distance between two crests or two troughs.
The frequency of a wave is the number of times a cycle occurs in one second.
The Greek letter, lambda (λ) is used to indicate wavelength.
Wave frequencies
Wave
Frequency
Radio waves
3 Hz GHz
Microwaves
300 MHz GHz
Infrared waves
300 GHz – 405 THz
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5. Transmission of radio- and microwaves
Works on the principle of producing a carrier wave.
A carrier wave is a set frequency that is used to carry data.
A carrier wave is mixed with the data signal. This process is called modulation.
A carrier wave must be at a higher frequency than the digital data signal.
The frequency range occupied by a modulated carrier wave is called the bandwidth.
A carrier wave with a width of 200 kHz has a bandwidth of 200 kHz.
The bandwidth of the carrier wave is referred to as a channel.
Carrier wave
Signal wave
Frequency modulated wave
Amplitude modulated wave

6. Transmission of radio- and microwaves
Modulation takes place during radio broadcasting. A transmitter generates the carrier wave and modulates information into the carrier wave.
A receiver receives the modulated wave and demodulates it.

7. Transmission of infrared waves
Infrared waves lies in between visible light spectrum and microwaves. It has wavelength of 700 nm to 1 mm and frequency ranges from 300 GHz to 430 THz.
Infrared waves is transmitted as a series of digital light pulses.
Infrared waves are used for very short range communication purposes such as television and it’s remote.
Infrared travels in a straight line so they are directional by nature.

8. Radio wave-based networking
There are three basic types of radio wave-based networking.
Wi-Fi:
Wi-Fi means wireless fidelity.
Wi-Fi operates on a higher frequency (2.4 GHz – 5 GHz) than cell phones.
Uses radio-waves to transmit information to and from the Internet or computer.
An access points act as a central transmitter and receiver of wireless radio signals.
Most computers and other devices contain built-in access points.
USB type wireless access point

9. Radio wave-based networking
Information from the access point is send to a wireless router.
The router converts it to radio-waves and beams it to a computer.
The computer interprets the radio-waves with the help of hardware (Access point) and software.
Wireless router
Mobile wireless router

10. Radio wave-based networking
Bluetooth:
The name ’Bluetooth’ reflects the Scandinavian origins of the technology. It is named after a 10th century Danish viking, King Harald Blåtand (translating as 'Bluetooth' in English).
Bluetooth is a short range wireless system designed for limited distances.
The frequency ranges from 2.4 GHz – GHz.
A Bluetooth network is referred to as a piconet or Personal Area Network (PAN).
A piconet
Two piconets linked
Bluetooth and toys
Bluetooth in medicine
How does Bluetooth work?

11. Radio wave-based networking
Cellular technology:
A cellular network or mobile network is a wireless network distributed over land areas called cells, each served by at least one fixed-location transceiver, known as a cell site or base station.
Radio-waves connect to designated areas referred to as cells.
A remote device (e.g. Mobile phone) connects to a radio transceiver within a cell.
Cell
Transceiver (base station)
How does a cell phone work

12. Electromagnetic spectrum
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