2. Infrared Transmission Infrared (IR) light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light Employed in short-range communication among computer peripherals and personal digital assistants and electronic devices
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4. Receiver uses a silicon photodiode to convert the infrared radiation to an electric current
5. Responds only to the rapidly pulsing signal created by the transmitter, and filters out slowly changing infrared radiation from ambient lightPropagation
7. Advantages Simple Circuit Cheap Low Power Consumption No Licenses Needed Higher Security Simple Shielding Portable
8. Disadvantages Works ONLY on Line-of-Sight (LOS) Mode Short Range Blocked by common materials: people, walls, etc Low bandwidth Speed is comparatively slow
10. Radio Transmission Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light
11. Propagation Radio waves travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space Information is carried by systematically changing (modulating) some property of the radiated waves, such as amplitude, frequency, phase, or pulse width
13. Advantages Simple Circuit Cheap No Licenses Needed High Speed/Bandwidth Covers Large Areas (Penetrates through walls)
14. Disadvantages Limited number of free frequency bands Shielding is difficult Interference with other electrical devices Greater Power Consumption Limited Spectrum of Frequency