Posted by Green Xenon [Radium] on 09/23/07 21:29

Hi:

One major reason the luminance signals of television are broadcasted on
an AM-carrier instead of FM is because FM requires large amounts of
bandwidth. Is there a way to use FM video without hogging so much bandwidth?

Quotes from
http://groups.google.com/group/sci.electronics.basics/msg/0c013cf5371da8dc?hl=en&
:

>Multiple-level quadrature modulation,
>"constellation modulation",
>is most common for packing
>lots of bits per Hz of bandwidth.
>The more you pack,
>the better the s/n ratio has to be.

>http://en.wikipedia.org/wiki/Quadrature_amplitude_modulation

>http://en.wikipedia.org/wiki/Constellation_diagram

Does this mean that Quadrature Modulation and Constellation Modulation
can -- at least in theory -- be applied to FM video so that excessive
bandwidth is not needed? If so, then what would be the minimum
radio-frequency required to transmit the video signal?


Thanks,

Radium

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