[sdiy] using CCD's as BBD's in audio circuits revisited

[Tom Arnold]

On Tue, Mar 28, 2006 at 07:09:33PM -0500, anthony wrote:
> So really could I just set the circuit up like the datasheet shows and then 
> add in the low-pass filters and the clock that I want to use (CD4047) along 
> with the LFO (whatever I feel like - I have several on protoboard)?

A quick glance shows that that unit is probably too new to use.  Its
photodiode based with a shift register on each side, so you sample the
levels into the shift register and then shift them out.

The ones I played with were much older ( 80's ) and didnt gate the data out
of the photocells, but actually read them out live.  When you hit the enable
pin the levels in the CCD no longer dropped[1] and then you shifted the data
out.  To read the next line you opened the shutter[2]  again to expose it, then
close and shift out the data.  How I made noise was to stick an LED on one
end and never close the shutter and then constantly shifted data out
ignoring the appropriate sense lines.

I stopped playing when I saw the Chinese BBD clones show up.

[1] By no longer dropped, I mean no longer dropped except as much as a
normal BBD cell would be expected to drop, which is a lot.

[2] Not a mechanical shutter, no idea how it worked.

-- 
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 - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org 
 - SynthGeek        -
 - BBD Fanatic      -  "...is it a virus, a drug, or a religion?" 
 - echo evho wjxo   -    Juanita Shrugs. "What's the difference?" 
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