How to subtract one signal from another, using an oscilloscope?

[GengisKhan]

I have two chaotic oscillators, which I am trying to synchronize. There is an oscilloscope, whose channels are linked to each oscillator. I need to subtract B-oscillator's signal, from A-oscillator's signal, using the oscilloscope, so that I can find the how much is the error between them. A-B would work just fine, but there's only A+B. Is there any way to do this, without having to add extra circuit parts? If not, what should I add, to subtract one signal from another?

Edit: I am using the classic Multisim 13.0 oscilloscope.

[aa232004 · Accepted solution]

hello.

you can invert signal B -

the standard 2 ch scope has inversion for channel B - there are 4 small buttons on the bottom of chB instead of only 3 for chA.

best regards

Michael

[GengisKhan]

Thanks a lot!