ONE FORMULA, ONE ANSWER
Cascaded Noise Figure Calculator
Combine the power gain and noise figure of an ordered list of stages using the Friis cascade relation. Choose input units and calculate one value within the stated conditions.
Inputs
Calculations run in this browser. Scientific notation such as 1.2e-3 is supported. Do not group thousands.
Result
Overall cascaded noise figure NF
Enter values and select Calculate.
F_total = F₁ + Σᵢ₌₂ⁿ (Fᵢ−1)/(G₁…Gᵢ₋₁); NF = 10 log₁₀F_total
Assumptions
Add stages in order from input to output. Both power gain and noise figure are entered in dB; 0 dB gain means unity and negative gain means attenuation. Required: a common frequency and 290 K noise reference, matched interstage connections and uncorrelated added noise. Noise figures are nonnegative. Excluded: impedance mismatch, reverse coupling, oscillation, compression and differing mixer sideband conventions.
Displayed values are floating-point approximations. Design safety factors and unprovided error contributions are not calculated.
Formula references and credits
NaNa Lab created the code, descriptions, icons and preview images. Text, figures and code from the linked references have not been reproduced.
Physical constants: NIST / CODATA 2022. The values of μ₀ and ε₀ are measured recommendations, not exact defining constants. Values and precision notes are in the source record.
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