SNR Calculation-System

[steppermotor]

I'm trying to do a SNR calculation

INPUT-->LNA--->LPF

For example: If the input is 14 db, and the lna has a gain of 20db, and NF=3db, and the LPF filter has a insertion loss of 3dB

If I wanted to find out the SNR after the LPF. Is it right to do the follow:

14 + 20 -3 = 31 db? or do I need to take the NF of the LNA into account. I'm not sure if there is a standard formula I should be following.

 

[Abhishekabs]

Read what is SNR first.
You are in wrong path.

your calculation is just system loss calculation.

Read some good receiver book or check wikipedia for SNR & NF of receiver.

 

[steppermotor]

I would say Input SNR-NFAmpl-InsertionLossLPF upon further research, but why isn't the gain affecting the calculation.

Read what is SNR first.
You are in wrong path.

your calculation is just system loss calculation.

Read some good receiver book or check wikipedia for SNR & NF of receiver.