Wireless technology. Electromagnetic waves Transmission of radio-waves and microwaves Transmission...
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Transcript of Wireless technology. Electromagnetic waves Transmission of radio-waves and microwaves Transmission...
Wireless technology
Wireless technology
Electromagnetic waves
Transmission of radio-waves and microwaves
Transmission of infrared waves
Radio wave-based networking
Electromagnetic waves
• 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
Trough
One cycle
Electromagnetic spectrum WavelengthMore
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.
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Wave Frequency
Radio waves 3 Hz - 300 GHz
Microwaves 300 MHz - 300 GHz
Infrared waves 300 GHz – 405 THz
Wave frequencies
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
Carrier wave
Signal wave
Amplitude modulated wave
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.
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.
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
• 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.
Radio wave-based networking
Wireless router Mobile wireless router
• 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 – 2.585 GHz.
• A Bluetooth network is referred to as a piconet or Personal Area Network (PAN).
Radio wave-based networking
A piconet Two piconets linked
How does Bluetooth work?Bluetooth in medicineBluetooth and toys
• 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.
Radio wave-based networking
Transceiver (base station)Cell
How does a cell phone work
Electromagnetic spectrum
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