Looking over some synth stuff lately, decided to look at phase distortion synthesis (again). I've already known about this for a while, but I figured I was on a wiki tangent and revisiting stuff I've already read can still be fun/interesting/etc. I was looking over the resonance filter Casio did in the digital domain. Then it dawned on me, if the carrier waveform was square, you wouldn't necessarily need to apply the volume modulation/short cycle envelope to remove the nasty restart point of the waveform. Using a NES mapper that supports external interrupts, and doing a 2 scanline INT (7.68khz) - you could apply a 16bit phase accumulator in software and have it reset (sync) a square waveform pointer for the corresponding channel. Applying a low frequency envelope, you can control sync modulator frequency giving you a sweep - brightness control.
Has anyone done something like this for the NES or such sound hardware? I understand the resource/overhead might be a bit high for NES, but I'm just interested to see (hear) what it would sound like.
Edit: Oh, SID has hard sync. One channel's overflow (or MSB) causes sync on a corresponding channel's waveform output. Anyone have a link to this specific sound?
Has anyone done something like this for the NES or such sound hardware? I understand the resource/overhead might be a bit high for NES, but I'm just interested to see (hear) what it would sound like.
Edit: Oh, SID has hard sync. One channel's overflow (or MSB) causes sync on a corresponding channel's waveform output. Anyone have a link to this specific sound?