VCDO - asking again + new idea

[Mikko Helin]

jbv:

[nice description of a digital waveshaper deleted]
>
>Yes, I know it's not the cheapest solution for a VCDO, but my estimation
>is that it should come for
>less than $30.00. The other interesting thing is that a regular VCO can
>be used.
>
There will still be the same problems in tuning, you'll need a very
good VCO. I think the most significant advantages of a VCDO are
the tuning stability followed by the ability to create some unique
waveforms. 

I have some ideas how to make a VCDO of a 16-24 bit ADC (serial)
+ EEPROMS + SCENIX SX-28 PIC compatible processor + 24 bit DAC for 
under $50.

Crystal's site (www.crystal.com) has information how to connect
their ADC's to PIC, you just "interleave" this code with a code
that reads linear-to-exponential conversion table in EEPROM,
increments the phase accumulation register(s) by the conversion result,
reads the waveformat in another EEPROM or calculates it on the fly,
and outputs the serial data in I2S format to a HIFI DAC. I call
the code "interleaved" as you work bit by bit and clock signal
by clock signal controlling everything in tightly timed
loop (at max 100MHz speed, see www.scenix.com). That thing would
be a real killer for VCO's ...

-Mikko

>