Wavetables....another idea....

[Magnus Danielson]

>>>>> "CC" == Chris Crosskey <chrisc at zetnet.co.uk> writes:

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

Well, there is such things as sigma-delta D-to-As.

However, the amount of information that a sigma-delta spits out is
higher than the amount of information that is kept in the sample PCM
endcoding. Thus, it is better to store the samples in 16bit or
whatever than to store them in their sigma-delta encoded form.
Also noteworthy is that sigma-delta's kind of depend on the filters
being used, so varying the sample-speed much may not be so great.

Nice try thougth.

Cheers,
Magnus