From the Synthtech website:
The MOTM-120 is based on an article in Electronotes, updated with improved and added features.
The MOTM-120 contains two four-stage sub-octave dividers, a digital multiplexer, and four digital ring modulators. It operates in one of two modes, SUB and CROSS.
In the SUB mode a single input is fed into the A IN jack. A four-bit binary counter is clocked with the input signal. This generates the lower four sub-octaves. These are then mixed by individual pots along with the input signal. A switch selects either the original source mixed in or a squared version of the input.
In the CROSS mode both A and B input signals are required. Each is divided into their respective sub-octaves and then each corresponding sub-octave is digitally ring modulated with the other. If A IN is audio, but B IN is from a LFO, you hear a 16-cycle pattern of the sub-octaves getting multiplexed in. As the B IN signal is raised into audio frequencies, the results are huge chordal timbres with lively beat frequencies.
The Tellun DB-120R daughterboard adds these features:
- Switchable AC/DC coupling for the outputs
- A +/- 5V pulse output for each sub-octave
- Weighted sum output STAIR for staircase wave generation
MOTM-120R panel photo by Scott Juskiw