Voice synthesis on ISR

I've just fixed a bug in the PSG version and padded the rom to 16KB because openmsx does not like 5KB roms
PSG audio should be improved a bit. Try it again if possible

PS
the size is 15 bytes per frames under SCC and 9 bytes per frame on PSG

Here we have a sample of ISR Speech: Sky Jaguar

For sure it can be improved but the first step is the hardest.
Many thanks to you ARTRAG for your great coding skills and your enthousiasme.

@JohnHassink Yeah!

And a new demo with a fixed bug: Sky Jaguar 2

ARTRAG, 2 PGS working here.
With a PC tool it will be easiest to find the optimal band pass for the waves.

I've updated the rom adding in the data a double separate encoding for volumes, one linear for SCC, one logarithmic for PSG.
In the initial release I was converting SCC volumes to PSG volumes "on fly", but this was reducing the accuracy for lower levels in the PSG replayer.
Anyway, the PSG sound improves only slightly, because the levels of the encoded tones are almost always in the high range of the amplitude scale. I'm willing to test a 8 tone vocoder using both PSG and SCC at the same time. It should give a data rate of 24 bytes per frame (1,2-1,4Kb/s) and start to became comparable to telephone quality.
WIP... ;)