Ryan what are you talking about? You're making no sense again. No diagram, no reference.If you're talking about common mode gain, yes it can be more than 1. But this is not used. We talk about Common Mode Rejection Ratio (CMRR)- the common mode gain divided by the differential gain. Since the amplifier is designed for differential gain, the common mode gain is always less than the differential gain, the CMRR is ALWAYS less than 1. It is usually expressed in dB. Here's an article:https://www.analog.com/media/ru/training-seminars/tutorials/MT-042.pdf
You said: ACM by definition is Vcm/Vout. NO!!Any amplification is VOUT / VIN. VIN here is VCM. So it's ACM = VOUT / VCM.Please take more care when posting, it's no wonder you are so easily confused....
