ring mod using op amps

[smccusker]

Is it possible to design a ring mod type effect using summation and differential op amp circuits?

something like that?

just conceptually i mean, not whether this actual circuit will work.

[Peter Snowberg]

Ring modulators output the sum and difference in frequencies between the program and carrier signals. The frequency part is the curcial part of the description.

[Tim Escobedo]

http://www.elecdesign.com/Articles/Print.cfm?ArticleID=11935

ISTR someone on SDIY had some success with this idea.

[R.G.]

You could just use the opamp +1/-1 polarity flipper.

[Paul Perry (Frostwave)]

I wouldn't call that circuit a 'ring modulator'.
True, most any highly non-linear circuit will produce some sum & difference frequencies from signals fed into it. But if you want to avoid the annoying continuous bleedthrough of the carrier signal, then you are going to have to go witha traditional approach.. such as a balanced transformer & diodes, or some kind of accurate multiplier like an AD633.
Things are a lot simpler in the RF world where it's easy to use a sharp tuned coil filter to pull out the frequency you want.
OK, using the carrier to flip the other signal works to generate harmonics.... but I think you will get tired of it real fast!

[GFR]

http://www.elecdesign.com/Articles/Print.cfm?ArticleID=11935

ISTR someone on SDIY had some success with this idea.

With that bunch of opamps and diodes you could well do a true multiplier, like exp(log(x)+log(y)).

You can get the same effect of the link if you:

You could just use the opamp +1/-1 polarity flipper.

That's a single opamp and a single diode.

[brett]

Hi
A balanced modulator, that flips between a normal and inverted signal, is aurally very close to a ring modulator even if it is technically different.  Bleed-through can be made quite small, and gating is non-existant.  A TLC555 timer driving some cmos switches works fine.

This approach is used in the $5 "robot voice" electronics kits.
cheers