From Yamaha Wiki
The Yamaha YMF262, also known as the OPL3 (OPL is an Acronym for FM Operator Type-L), is an Frequency modulation synthesis Sound chip. It is an improved version of the Yamaha YM3812 (OPL2). It adds the following features:
- twice as many channels (18 instead of 9)
- simple stereo (hard left, center or hard right)
- 4 new waveforms (alternating-sine, "camel"-sine, square and logarithmic saw)
- 4 oscillator mode (combines 2 channels together, for maximum 6 channels)
- less time spent Busy-wait for a response from the chip, improved Latency (engineering) and system performance (the OPL2 required fairly long delays)
This chip is used for the Sound Blaster, Sound Blaster and MSX OPL3 Cartridge. The functions of the YMF262 is included in its successor, the Yamaha YMF278 (OPL4).