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Formulas use in Satcom

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Ex Member
Ex Member

Apr 8th, 2012 at 4:06pm  
Dear Mr.Eric

Can you provide me all the formulas use in satcom like bandwidth calculation, center frequency , symbol rate , occupied bandwidth for SCPC and as well as in DVB-S2 , It will be nice if you help me in this , my email id is leoboy89@gmail.com

Best Regards,
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Eric Johnston
Senior Member

Posts: 2109
Reply #1 - Apr 8th, 2012 at 7:18pm  
As a baseline I suggest:
The occupied bandwidth = 1.19 to 1.2 x symbol rate.
The allocated bandwidth = 1.35 to 1.4 x symbol rate.

Allocated bandwidth is the amount of bandwidth you need to rent from the satellite transponder.  The satellite owner will decide, based on information about your carrier (symbol rate, power spectral density, filtering, frequency stability) so that you do not suffer unacceptable interference into your carrier from others or for you to cause unacceptable interference to others.  

If you have multiple adjacent carriers then, with agreement of the NOC, you can decide for yourself the spacing between your carriers.  If you move the carriers closer, your adjacent channel interference increases.

The shape of a DVB carrier is shown here:
Best regards, Eric.
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