I've been kicking this around for a few days. I know I'm overlooking something simple it has been a long time since I've had to do this. I'm trying to sketch the output in the time domain of a 1 kHz square wave passing through a communication channel whose bandwidth is 0 to 10 kHz. I'm trying to apply: f(t) = Ao/2 + A1 cos ωt + A2 cos 2ωt + B2 sin 2ωt + ... I'm just looking for direction here I believe I'm on the wrong track as I can't wrap my head around the equation without a known voltage.