WIRELESS TRANSMISSION

     Wireless transmission is a form of unguided media. Wireless communication involves no physical link established between two or more devices, communicating wireless. Wireless signals are spread over in the air and are received and interpreted by appropriate antennas. When an antenna is attached to electrical circuit of a computer or wireless device, it converts the digital data into wireless signals and spread all over within its frequency range. The receptor on the other end receives these signals and converts them back to digital data. Click here

Radio Transmission

     Radio frequency is easier to generate and because of its large wavelength, it can penetrate through walls and structures. Radio waves can have wavelength from 1 mm - 100,000 km and have frequency range from 3 Hz (Extremely Low Frequency) to 300 GHz (Extremely High Frequency). Radio frequencies are sub divided into six bands. Radio waves at lower frequencies can travel through walls whereas higher RF can travel in straight line and bounce back. The power of low frequency waves decreases sharply as they cover long distance. High frequency radio waves have more power. Lower frequencies such as VLF, LF, MF, bands can travel on the ground up to 1000 kilometers, over the earth's surface.

Microwave Transmission

     Electromagnetic waves above 100 MHz tend to travel in a straight line and signals over them can be sent by beaming those waves towards one particular station. Microwaves travels in straight lines, so both the sender and the receiver must be aligned to be strictly in line of sight. Microwaves can have wavelength range from 1 mm - 1 m and frequency ranging from 300 MHz to 300 GHz.

Infrared Transmission

     Infrared wave 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 wave is used for very short range communication purpose such as television and its remote. Infrared wave is used for very short range communication purposes such as television and its remote. Infrared travels in a straight line hence it is directional by nature. Infrared waves can not cross wall, because of high frequency range.

Light Transmission

    Highest electromagnetic spectrum which can be used for data transmission is light or optical signaling. This is achieved by means of LASER. The light travels in straight line, because of frequency, uses by light. Hence the sender and receiver must be in the line of sight. LASER transmission is unidirectional, so at both ends of communication the LASER and the photo-detector needs to be installed. LASER beam is generally 1 mm wide hence it is a work of precision to align two far receptors each pointing to LASER source.

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