Yes, in our case -- and in the general case, PPG can be assumed to stand for Photoplethysmogram. Also I'm not aware of any examples where "Photoplethysmogram" w

Yes, in our case -- and in the general case, PPG can be assumed to stand for Photoplethysmogram. Also I'm not aware of any examples where "Photoplethysmogram" was used as a "Penile (PHOTO)-plethysmography", generally what I've read on "Penile plethysmography" are more direct measurements of the penis itself, not optical measurements of blood flow elsewhere on the body. Because of that, I don't think it's reasonable to call Apples "touch sensing and haptic feedback technology the 'Faptic Engine' " at this time! but it is a funny pun! We merely entertained the idea that it might be possible to use machine learning to infer erection status from a ppg sensor somewhere else.