The Yamaha YMF262, also known as the OPL3 (OPL is an acronym for FM Operator Type-L), is an FM synthesis sound chip. It is an improved version of the Yamaha YM3812 (OPL2), adding the following features:
- twice as many channels (18 instead of 9)
- simple stereo (hard left, center or hard right)
- 4 channel sound output
- 4 new waveforms (alternating-sine, "camel"-sine, square and logarithmic sawtooth)
- 4 oscillator mode, pairing 2 channels together to create up to six 4 oscillator FM voices
- reduced latency for host-register access (the OPL2 had much longer I/O access delays)
The YMF262 was used in many sound cards, including the popular Sound Blaster Pro 2.0, Sound Blaster 16 ASP and AWE family.
Like its predecessor, the OPL3 outputs audio in digital-I/O form, requiring an external DAC chip like the YAC512. Competing sound chip vendors (such as ESS, OPTi, Crystal and others) designed their own OPL3-compatible audiochips, with varying degrees of faithfulness to the original OPL3. Yamaha's later PC audio controllers, including the YMF278 (OPL4), the single-chip Yamaha YMF718/719S, and the PCI YMF724/74x family, included the YMF262's FM synthesis block for backward compatibility with legacy software. See YMF7xx for more information.