[sdiy] Rectifier for logic level pulse?

[John Mahoney]

At 07:22 PM 9/28/2009, Tim Parkhurst wrote:
>Hello Y'all,
>
>... Essentially, what I need is a circuit that produces a
>short positive-going pulse when the input goes low to high (that's the
>easy part) AND another positive-going pulse when the input goes from
>high back to low (the not so easy part). ...

<brainstorming>
Split the signal and run one side through a normal detector. Invert 
and offset the other side; now run that through the same kind of 
detector, because what was a falling edge is now a rising edge. 
Combine the 2 outputs. Done. The negative side will want to send a 
pulse on startup, I guess, so you may need to handle that.
</brainstorming>

John