Is there any expert who knows how the SNR result in the RF Budget Analyzer is calculated? Why is it inconsistent with the value I calculated?

The way I calculated is:SNR=0-lg(KTB)=0-10lg(1.38*10^-23*290*100*10^6)=123.9772

There is a difference of 30 dB from the simulation result. Which part is wrong?

Answer 1

[David Goodmanson]

Hi ZW,

It's good to work out things independently as you are doing. The available power is 0 dBm, i.e. 1 milliwatt = -30 dB watts. So now you have

-30 -10*log10(1.38*10^-23*290*100*10^6)

which basically matches the result.

(Using more decimal places for the Boltzmann constant, k = 1.38065e-23, matches the result to all four decimal places).

[志刚]

It was really an enlightenment to me. Moreover, you carefully pointed out the issue of the accuracy of the value of the Boltzmann constant. Thank you DG so much!

[志刚]

Hi，DG@David Goodmanson：

Do you know the reasons for the following two questions? As shown in the figure，

First, why the SNR remains unchanged after cascading?

Second, the OIP3 value after cascading is also different from the result I calculated.

The calculation methods I used for the cascaded SNR and the cascaded OIP3 are as follows.