Ring mod

gentleclockdivider · July 2023

I am having a discussion with Urs about ringmod in zebra .

In zebra when multiplying 2 bipolar signals the result is a waveform with only energy above the zerocrossing line .

When multiplying two bip. signals in reaktor , it's a healthy ac waveform both +1,-1 ( screenshot 2 )

Urs said that the ringmod in zebra is a textbook example and just uses multiplication and oversampling -downsampling , how come the result in zebra has an offset ?

Examples show two sine wave multiplied

colB · July 2023

There is a bug in zebra or something else is post or preprocessing the signal or Urs is just wrong. I've built a few 'textbook' models of proper diode ring mods and also more modern 4 quadrant mutipliers, and also used various hardware ring mods. They all produce symmetrical bipolar output.

colB · July 2023

The best breakdown of how a true ring mod works is here:

(Fwiw, Analog devices is a major electronics component manufacturer)

https://wiki.analog.com/university/courses/electronics/electronics_lab_diode_ring_modulator

...but just go to Wikipedia for some more evidence.

colB · July 2023

You will get a positive only signal if both inputs are identical. In that case you are squaring the input, so obviously all the output will be positive. That's not what the pic looks like though...