Noise Figure Cascade

Problem

Return the total noise factor of a receive chain using the Friis formula, all in linear units:

F = F1 + (F2 - 1) / G1 + (F3 - 1) / (G1 * G2) + ...

factors[i] are the linear noise factors of the stages and gains[i] the linear gain of stage i (so gains[i - 1] precedes factors[i]).

Hint

Later stages matter less because earlier gain suppresses their contribution.

case 1

in: [[2,3],[10]]

expected: 2.2

case 2

in: [[1.5,2],[4]]

expected: 1.75

case 3

in: [[2,3,4],[10,5]]

expected: 2.2600000000000002

case 4

in: [[1,5],[2]]

expected: 3

Starter codePython

def noise_figure_cascade(factors, gains):
    # Your code here
    pass

4 test cases · run your code against them in the editor