let’s say I have a channel with 2 amplifier stages, each has an SNR of 25dB and 24dB. The initial SNR of the signal is 30dB. Can anyone clarify how to calculate the SNR after each amplifier and the uncertainty at the end if all SNR have +/- 1dB uncertainty? (Since it involves log, I wasn’t sure to use normal uncertainty equation for adding)
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Dear Chathu
Thanks for your question!
First step is to calculate the SNR after the first and second amplifiers and second step is to propogate the uncertainties.
SNR after_amp1 =30+25=55dB ±1dB
SNR after_amp2 =55+24=79dB ±1dB
To propagate uncertainties, you add the uncertainties in quadrature. The formula is:
The total uncertainty after the second amplifier:
Therefore, the SNR after the second amplifier, considering uncertainties, is 79 ± 1.41 dB
Hope it helps!
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