I've heard this term used to describe a ring modulator that has a function that keeps the carrier signal the same note as the guitar's. I been wondering if there is a ring mod pedal out there that works similar to a pitch shiftier where the carrier signal can "harmonize" with the guitar.

For example, play an A note and lets say the carrier is B. Then play an A# and the carrier will be a C. Basically sounding the same as a normal ring mod but being more predictable.