# Biasing AC signal - which circuit is the best?

I've seen a similar question asked earlier here: How do I bias an AC signal for sampling?

However, I have a 3 different circuits and I am not sure which one works best!

I have: +-2V AC signal of varying frequency (5hz to 10kHz). It is biased around 0V.

Objective: Shunt this signal from 0V to 3V, so the output is 1 to 5V signal (the same +-2V just biased around 3V) like demonstrated here:

Solution 1: Single Non-inverting Unity gain Op-Amps Here I cheated a little bit by increasing the AC signal from +-2v to +-4V, because the summing amp in this case forms a voltage divider

Simulation: Transient and AC

Solution 2: Two Inverting Unity gain Op-Amp in series By adding 2 inverting op amp in series, we can add to signals without "cheating" and scaling the input signals.

Simulation: Transient and AC

Solution 3: Three Non-Inverting Unity gain Op-Amps Why? Well, the AC signal source has some impedance, so to avoid any discrepancies on the summing op amp input, I thought it would be logical to put both the AC and DC components through unity gain buffers first...

Simulation: Transient and AC

All three circuits work and the output signal is in fact 1 to 5V in all three cases. Which solution is the best?