Wireless technology

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

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 More Wavelength

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 - 300 GHz Microwaves 300 MHz - 300 GHz Infrared waves 300 GHz – 405 THz Back

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

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

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

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 – 2.585 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?

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

Electromagnetic spectrum Back