Why (AM) is used for video while (FM) is used for voice in t

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anwer_sbh

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Why (AM) is used for video while (FM) is used for voice in the TV broadcasting?
 

Re: Why (AM) is used for video while (FM) is used for voice

Without going into too much baffling technical details, FM occupies much more RF spectrum than AM, and if you realize that video signal has the bandwidth of ≈0-6MHz, whereas audio has "only" 0-20kHz, the conclusion is just that: to save precious RF spectrum analog video uses AM modulation and analog audio FM modulation ..
This is, however, not the story in satellite and fiber optic video transmission ..

If you would like to calculate bandwidths of AM and FM goto:
**broken link removed**

Regards,
IanP
 

Re: Why (AM) is used for video while (FM) is used for voice

In PAL and NTSC audio is FM and video AM. But in SECAM video is FM and audio is AM. The reason for video AM in PAL and NTSC is less bandwidth.
SECAM uses FM for video by scaning only odd or even lines - so less bandwidth results and other benefit is the receiver is much simpler.
 

Re: Why (AM) is used for video while (FM) is used for voice

Above statement about FM SECAM is not true. Video transmission in SECAM is also AM. The difference between PAL and SECAM crominance signal (colour component of video baseband signal) is that at PAL a type of AM is used and FM in SECAM.
For further reduction of channel frequency bandwidth is acheived by so called Vestigial Side Band technique where lower side band is reduced to up to 1MHz (nominal is 5MHz). Channel bandwidth is only 6MHz for B/G system.
 

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