A pitch modulating circuit using a s/h waveform lfo. Generates a variety of sounds from subtle pitch variation to total poop digital breakdown.
Period: This knob controls the period of the s/h wave form. (Essentially the speed or rate of the LFO).
Mix: This allows you to blend the clean sound going into the pedal with the effected sound coming out of the pedal. One extreme => just clean, the other extreme => just effected signal.
Volume: A master output level control.
Mean: The end result of this knob is not simply explained and its result is highly interactive with the skew knob. It will affect several things sonically. At min the effect will be subtle and the sound quality will be quite high. As the knob is rotated the probability of glitchy sounds will increase, however their will be some headroom where quite normal sounding tones will be produced.
Skew: This knob is interactive with the mean knob. It will in effect control the variation of pitches that is produced. However this range is also somewhat controlled by mean. An example: Mean somewhere in teh middle and skew quite low will result in just small pitch variations. With skew increased the pitch variation between the output tones will be more varied.
The best way to get a feel for what these knobs do is to watch the sample videos...
sample with clean guitar here