Wavetables....another idea....

[Martin Czech]

> Hi folks, 
> 
> Is there such a thing as a sigma-delta D-to-A? It strikes me that it would be 
> easy to program up an SRAM with a simple step-switch, on-switch interface (take 
> a while but you could also use EPROM's....it's an easy idea, and you could 
> automate the loading if it was VC, ie LFO to provide step frequency, if swich 
> I/P sees more than 5V it's a <1>, if it  doesn't then it's a <0>, then use the 
> same sort of VCO driver that any other hybrid osc is going to need...
> 
> JAT
> 
> chrisc

The second formant book shows a sigma/delta converter for a delay.
With sigma delta you can only process ac, some kind of "reset" logic
has to be applied in order to get proper absolute voltage levels.

m.c.