Dupicate LFO Signal and Invert, keeping MAXs and MINs

Question

Im working on a Dual LFO with "Depth" and Rate controls. I already got the "root" LFO signal working and if I do this, I can generate the LFO swinging from 0v to 9v... and with Less Depth from, say, 8v to 9v:

Now I need the same signal but with the direction inverted (when the first one goes up, the second one goes down) BUT having the same Maxs and Mins.

If I do this (img below), with Depth at minimum I get, say, 8v to 9v in the first one, but 0v to 1v in the second one...

and I want the same 8v to 9v, but with the orientation being the inverse, like this:

Things I already know how to do:

• Invert a signal
• Add DC Offset to signal (but the offset always changes depending on the Depth)
• Remove DC Offset to signal
• Substract two signals
• Sum two signals

I need to figure this out!! There has to be a simple way!

UPDATE::

I came up with this math: 9v - 2 * Signal(without offset, centered on 0)

Based on that I made this simplification for testing the concept where I generate the two signals: LFO1 goes from 7 to 9 AUX_SIM goes from -1 to 1 (just LFO1 without the offset)

And it works:

SO, then I generate the AUX_SIM from LFO1 removing the offset and is ok:

BUT when I put it all together, The LFO1 without the offset is not centered on Cero and everything shifts, because life is HARD :D

I thought I was close this time... Any ideas??

Answer 1

This may do what you want but, I would run it through a simulator first if I were you: -

You should also make sure that you have power rails on your op-amp that are in excess of 9 volts and preferably 12 volts (for most bog-standard op-amps). I mention this because you didn't say what power rails the op-amp receives.