Suppose I have a digital signal, or at least a signal that is gnd referenced. Like a NTSC video signal for instance like this:
Then I have a single supply opamp, and I want to amplify this by 2x say. I think that if I just input this to a simple opamp circuit with 2x gain that my signal will clip because it will be amplified around my virtual GND.
So then instead I have to add a DC offset probably equal to my virtual gnd voltage so I can amplify without clipping? I think I understand that to be true but maybe my understanding is wrong.
Then my last question is after I've done this and amplified the signal the output is going to be centered around my virtual gnd voltage. So how do I get my signal back to DC (assuming my receiver is not AC coupled and he expects levels referenced to 0V DC). I can't just subtract the DC offset, since my signal amplitude will vary I don't know the right amount to subtract.
I've read a little bit about DC restoration circuits, but I'm not sure if I'm on the right path or not.