Summing node/S+H generator question

[tomg]

On 09-Jan-99, halfmast at clubmet.metrobbs.com wrote:

>As my first experiment with sample and hold, I sampled some white noise
>and applied the output to an attenuated CV input of my VCO.  A problem
>arose as I lessened the attenuation.  A peak detector connected to the
>summing amplifier of the VCO would register 2.5v (which is really only
>half of the s+h's theoretical swing--it gives +-5v unattenuated), the
>VCO's frequency would go up past an audible level, and then the peak
>detector reads 12.5v. The thing is, the oscillator can handle such a
>swing when my LFO is controlling it; so why can't I get the full
>swing from the S+H?  I should probably also add that it would never
>reach the high frequencies without becoming unstable, and that the S+H
>never has problems when its not connected to the VCO.  Any ideas?
>Thanks in advance for any input.

>Evan Keller
>halfmast at clubmet.metrobbs.com


This works very well. Super simple sample and hold w/clock.

1 dual op-amp
2 fets
1 npn

http://www.mindspring.com/~vco/misc/ssh.html

-tg

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