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Infrared and radio transmission
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Transcript of Infrared and radio transmission
Infrared &
Radio Transmission
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
• Uses infrared light-emitting diodes
• Receiver uses a silicon photodiode to convert the infrared radiation to an electric current
• Responds only to the rapidly pulsing signal created by the transmitter, and filters out slowly changing infrared radiation from ambient light
Propagation
Uses
• Short Range Communication
• Indoor use
Advantages
• Simple Circuit• Cheap• Low Power Consumption• No Licenses Needed• Higher Security• Simple Shielding• Portable
Disadvantages
• Works ONLY on Line-of-Sight (LOS) Mode
• Short Range
• Blocked by common materials: people, walls, etc
• Low bandwidth
• Speed is comparatively slow
Examples
• Remote Control
• Mobile Phones
Radio Transmission
• Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light
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
Uses
• Audio• Telephony• Video• Navigation• Radar• Data (Digital Radio)• Radio control
Advantages
• Simple Circuit
• Cheap
• No Licenses Needed
• High Speed/Bandwidth
• Covers Large Areas (Penetrates through walls)
Disadvantages
• Limited number of free frequency bands
• Shielding is difficult
• Interference with other electrical devices
• Greater Power Consumption
• Limited Spectrum of Frequency
Examples
• FM Channels
• Walkie Talkies