A filter window is multiplied before active gain squares the remaining budget. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Unity gain leaves the passive window budget unchanged
The passive window turns input budget 25 into 16. Gain 1 leaves final budget 16.
25⋅54⋅54⋅12=16
A fractional voltage gain still squares exactly
The same passive output 16 is scaled by gain 3/2. Squared gain sends the final budget to 36.
16⋅(23)2=36
Doubling voltage gain quadruples the budget
The passive window still gives 16. Gain 2 makes gain-squared 4 and final budget 64.