Noise Figure Calculator

Cascaded Amplifiers Noise Figure

Number of Amplifiers:

Formula: $$ F_{\text{total}} = F_1 + \frac{F_2 - 1}{G_1} + \frac{F_3 - 1}{G_1 G_2} + \cdots + \frac{F_n - 1}{G_1 G_2 \cdots G_{n-1}} $$
$$ NF_{\text{total}} \, (\text{dB}) = 10 \log_{10}(F_{\text{total}}) $$
Where $ F_i $ is the noise factor (linear) and $ G_i $ is the gain (linear) for each stage.

Noise Factor and Noise Figure

Enter one value to calculate the other.

Formula: $$ NF \, (\text{dB}) = 10 \log_{10}(F) $$
$$ F = 10^{NF / 10} $$

SNR (Absolute/Linear)

Enter two values to calculate the third.

SNR at Input (linear):

SNR at Output (linear):

Noise Figure (dB):

Formula: $$ NF \, (\text{dB}) = 10 \log_{10} \left( \frac{\text{SNR}_{\text{in}}}{\text{SNR}_{\text{out}}} \right) $$
$$ \text{SNR}_{\text{out}} = \frac{\text{SNR}_{\text{in}}}{10^{NF / 10}} $$
$$ \text{SNR}_{\text{in}} = \text{SNR}_{\text{out}} \times 10^{NF / 10} $$

SNR (dB)

Enter two values to calculate the third.

SNR at Input (dB):

SNR at Output (dB):

Noise Figure (dB):

Formula: $$ NF \, (\text{dB}) = \text{SNR}_{\text{in}} \, (\text{dB}) - \text{SNR}_{\text{out}} \, (\text{dB}) $$
$$ \text{SNR}_{\text{out}} \, (\text{dB}) = \text{SNR}_{\text{in}} \, (\text{dB}) - NF \, (\text{dB}) $$
$$ \text{SNR}_{\text{in}} \, (\text{dB}) = \text{SNR}_{\text{out}} \, (\text{dB}) + NF \, (\text{dB}) $$