SFDR (Spurious-Free Dynamic Range)

I checked some document and books.

Some wrote SFDR = 2/3 (IIP3 - Noise Floor)

Some wrote SFDR = 2/# (IIP3 - Noise Floor) - SNR(min)

where Noise Floor = -174dBm/Hz + 10log(B) + NF

Could you please advise which one is correct ?
Or the're defined in different cases ?

Thanks a lot.

from the microwave point the first one is right and for the decoder ,the second one is right, because the decoder want to decode the message, it must to consider the SNR

Hello,

Yes, the first one is correct....
Spurious-free dynamic range (SFDR) is two-thirds the difference between the 2-tone, third-order intercept point (IP3) and the minimum discernible signal (MDS).
SFDR = [(2/3)(IIP3 ? MDS)]


---manju---

Both are correct , the second one is more general form as if the minimum SNR=0dB (i.e. the noise equal to the signal) then u get the first form but if u need to have the minimum detectable signal larger than the noise by a certain factor (SNR_min) then use the second
regards,
Safwat