Fig. 2From: Overlapping PPM for band-limited visible light communication and dimmingTwo-level modulation and dimming schemes to obtain about 60 % dimming [1]. (1) OOK: considered as reference at 50 % dimming, (2) OOK + CT using Manchester line coding, (3) VPPM: pulse width of conventional 2-PPM is reduced from 1/2 to 3/8, (4) MPPM: 56 possible codewords, and (5) OPPM: 6 possible codewordsBack to article page