[sdiy] Idea - Triangle wave DCO core

[Scott Nordlund]

> Couldn't we use a leaky integrator? The DC drift problem is likely to occur over longer periods (seconds) and the lowest frequency is going to be in the tenths of seconds, say. So highpass the integrator to lose any DC. Or is that nonsense? I've only ever done it in the digital domain.
> 
> The idea was to do the vast majority of the work in the software and have almost no hardware. If I start adding comparators and switches and such like, it loses its charm and I might as well build a sensible VCO circuit.
> 
> Tom

Is the offset even a problem? Won't it just drift to the rail, then clip a tiny bit each cycle (equal to the drift over one period) and be stable from then on? I'd think the only requirement would be to design it so that the triangle wave spans the full range of what the integrator can put out.