Hi!

Could you explain me how to calculate the noise figure for the scheme using Diff-Amp calculator's results?

The source resistance is 50 OHm.

Hi!

Could you explain me how to calculate the noise figure for the scheme using Diff-Amp calculator's results?

The source resistance is 50 OHm.

Jino,

I want to optimize a system noise factor of a direct conversion receiver. The ADA4930 is used as low noise amplifier following a quadrature converter. To calculate the overall noise figure I need to know the amplifier stage. I tried to calculate as showed on the picture but I'm not sure it is correct because NF depends on a load resistance.

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Noise figure is usually not used with op amps. See:

http://www.analog.com/media/en/training-seminars/tutorials/MT-052.pdf

Harry

Hi,

Thank you for pointing that out. I have overlooked a certain formula and parameter. Anyway, it has been corrected in the attached file.

Regards.