Low-Pass Reduces Fast Signals - Electronic Circuits VII: Frequency Response and Filters Step by Step

A first-order low-pass transmits less above cutoff. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

The signal is above the cutoff

With cutoff 3 hertz, the index is 2.

x={6\over 3}=2

The low-pass squared ratio drops to one fifth

Budget 20 transmits only 4 through this low-pass stage.

|H|^2={1\over 5}