Christian Klippel wrote:
> Am Freitag, 17. November 2006 17:26 schrieb Steffen:
I read about it in Delton T. Horns Music Synthesizers: A Manual of
Design and Construction, if i recall correct, where the author
suggested to use a S/H in connection with such a converter to save
CPU power (when one wanted to keep a given CV for a period of time
(faster then the port)).
this is only usefull if you want to digitize a changing signal. you use the
s&h circuit (usually just a capacitor and a switch) to "freeze" the current
value, so it stays stable while you digitze it. to digitize a signal, you
basically need a dac, s&h and comparator. you load the s&h, set a value at
the dac, and compare the two voltages with the comparator. you change the dac
value so long until you have a match between the two voltages. then you
discharge the s&h, and go ahead with the next sample.
Not only useful for digitizing an analog sample into the digital world,
but also useful as a multiplexer. If you build a converter using one
single ADC, you could share it to say 8 channels by sending them one at
a time. Often (but not always) cheaper and easier than using 8 normal
ADC's. Multiplexing with S&H works even on a low pass filtered
PWM-signal if thats what someone (?) was planning on using...
mvh//Svante - with a homebuilt midi to 8-channel CV somewhere in some
drawer...
_______________________________________________
[email protected] mailing list
UNSUBSCRIBE and account-management ->
http://lists.puredata.info/listinfo/pd-list
