# Noise Figure budget analysis for power combiner & divider

1. ## Noise Figure budget analysis for power combiner & divider

Hi all

How to calculate the cascaded NF if there are power splitters & combiners in the path.

What should be the NF value for one power splitter & combiner component?  Reply With Quote

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2. ## Re: Noise Figure budget analysis for power combiner & divider

for every passive device the NF equals its own attenuation, so splitters have 3dB, and at combiners are not guaranteed the input signals are the same, thus they should have 0dB in that case I guess.

1 members found this post helpful.  Reply With Quote

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3. ## Re: Noise Figure budget analysis for power combiner & divider

NF=Insertion Loss  Reply With Quote

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4. ## Re: Noise Figure budget analysis for power combiner & divider

Then there won't be any improvement in NF after combining multiple signal(same frequency & amplitude) through one power combiner, am I right?  Reply With Quote

5. ## Re: Noise Figure budget analysis for power combiner & divider

If you combine two identical signal, perfectly in phase they amplitude will double while the noise (uncorrelated) will sum in power. Theoretically you can gain 3 dB NF. In practice you will have a lower gain since the two waveform will not be perfectly identical in phase and amplitude and also the combiner will have imperfections and losses.  Reply With Quote

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