[sdiy] How droopy is too droopy in a S & H?

[cheater cheater]

For pitch CV from DAC I suggest a very long averaging circuit, say 100 samples.
This means you get 18-bit quality from a 12-bit DAC. Generally add ~6
bits for every 64 samples (depending on how good your integrator etc
are).
Use two DACs and, when a new note is pressed, load up the 100 samples
from the unused DAC. If you start output from the averaging circuit
before it gets the right amount of samples, you'll get gross
inaccuracies (e.g. 1 sample at the right CV averaged with 99 samples
that have the wrong CV = very bad). Once the new note is 'loaded',
switch over and do the glide thingie.

Cheers
D.

On Tue, Jan 27, 2009 at 4:45 AM, Veronica Merryfield
<veronica.merryfield at shaw.ca> wrote:
> I'd probably build in the log conversion stage into the micro as well.
>
> If there was a pic or similar with two 12 bit DACs and a comparator, one
> could implement it with few external components.
>
> On 26-Jan-09, at 4:14 PM, John Luciani wrote:
>
>> On Mon, Jan 26, 2009 at 5:29 PM, mark verbos <mverbos at earthlink.net>
>> wrote:
>>>
>>> I can only imagine that working for me if 8 bits is enough for pitch.  ,
>>> since that's the biggest parallel converter I know of.
>>>
>>> It's probably not, Is it?
>>
>> I would go with 11 or 12 bits for pitch.
>>
>> Analog Devices has a number of 12 bit A/Ds and D/As that have 12 data
>> lines.
>> With some glue logic (or a simple uC or FPGA) you could do duals or quads.
>> Checkout TI and Maxim as well.
>>
>> (* jcl *)
>>
>> --
>>
>> You can't create open hardware with closed EDA tools.
>>
>> http://www.luciani.org
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