mist-devel / fpgagen

SEGA Genesis/Megadrive core, running on the MIST
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Updated to JT12 with PCM interpolation #52

Closed jotego closed 5 years ago

jotego commented 5 years ago

Updated to JT12 v0.65

-PCM sounds are now re-sampled internally at 55/2 kHz with a second order CIC filter for interpolation.

Upon inspection, it looks games tend to do sloppy PCM managing, not keeping a constant rate. I have not seen any software that is able to write PCM samples at full speed (55kHz), although the chip it self would support it. Reports say that at best you get 55/2 kHz as maximum rate. So I have added a fixed interpolation filter to double the PCM sample rate and align it properly with the output FM data rate.

PCM samples sound now better than before. Better than a real YM2612.