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Draw and explain electromagnetic spectrum for communication.
written 10.1 years ago by gravatar for teamques10 teamques10 ★ 70k •   modified 10.1 years ago

This question appears in Mumbai University > Mobile communication and computing subject

Marks: 5 M

Year: Dec 15, May 15
mobile communication
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written 10.1 years ago by gravatar for teamques10 teamques10 ★ 70k

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  • The transmission over the air (i.e. radio transmission) can take place using many different frequency bands. Each band has its own advantage as well as disadvantage.

  • The above diagram shows the frequency spectrum used that can be used for data transmission. It starts from 30 Hz and goes upto 300 THz.

  • Along with the frequencies are show the wavelength of the signals calculated by the formula: λ=c/f where c=speed of light in vacuum i.e. 3.8*108 m/s.

Band Range Details/Application
Very low frequency From 3 KHz onwards They are long waves, having large wavelength
Low frequency (LF) 30 KHz to 300 KHz Used by submarines due to their water-penetrating ability and can also follow earth’s surface.
Medium frequency (MF) 300 KHz to 3 MHz Used for radio broadcast using AM/SW/FM modulation techniques.,Also used for aircraft navigation
High frequency (HF) 3 MHz to 30 MHz Used for radio broadcast using AM/SW/FM modulation techniques.,Also used for aircraft navigation
Very,High Frequency (VHF) 30 MHz to 300 MHz TV broadcast range begins here:,Used for TV broadcast, Land mobile.
Ultra-High Frequency (UHF) 300MHz to 3 GHz WLANs, Analog-based mobile phones, cordless telephones, 3G cellular systems etc.
Super High Frequency (SHF) 3 GHz to 30 GHz Directed microwave links, radar, satellite
Extremely High,Frequency (EHF) 30 GHZ to 300 GHz Very close to the infrared region; also used for satellite, radar.
Infra-red 3 THz to 30 THz Used for directed links e.g. to connect different buildings via laser links.
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