Convert C/I3 to IP3 - RF Cafe Forums

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SatelliteRF

Post subject: Convert C/I3 to IP3

Posted: Tue Aug 25, 2009 5:27 am

Lieutenant

Joined: Tue Aug 25, 2009 5:20 am
Posts: 1

Have got some date but do not have the formula to convert C/I3 to IP3. I have the LNA gain(dB), input power level (dBm) and C/I3 (dBc). Could some one help me with the conversion? Thanks.

Mr. Tesla

Post subject: Re: Convert C/I3 to IP3

Posted: Wed Aug 26, 2009 12:35 pm

Lieutenant

Joined: Mon Aug 10, 2009 1:22 pm
Posts: 3
Location: Australia

I have never heard of a C/I3 equivalent of IP3, but there is a ratio of the carrier power to 3rd-order intermod product power.

http://www.maurymw.com/support/pdfs/5C-043.pdf

The IM3 power is governed by the standard equation:

P(IM3) = 3*P(input tones) - 2*IP3

That works for input or output reference.

So, knowing your carrier level, and the IM3 tone levels, simply subtract dB levels to get the ratio.

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