how do i invert a control voltage?

[ClockworkRobot]

Hi, i have a theremin module that's giving me a CV signal like this:
/
need it to go like this:
\
turn it upside down, see? make the high low and the low high
Can anyone with some synth experience tell me what you'd call such a process and if anyone has could point me to a circuit I could build? That's be brilliant?
Thanks.

[ClockworkRobot]

http://www.doepfer.de/DIY/a100_diy.htm
Inverting amplifier.

That'd do the trick, yeh?

[Raaku]

The Moogerfooger cp-251 would also do the trick. It has a mixer circuit that has a negative output in addition to the normal. You'll get the signal upside down when you plug just the theremins cv into the mixer, you don't have to mix the signal with anything although it's a mixer

The cp-251 has also other cool features: noise generator, LFO etc.

[ClockworkRobot]

oh I forgot the cp251 has that on it.. yeh that works a treat. I think I still want to build one in from scratch but that does the business for now.