Trigger and gate + SH
It produces trigger and gate signals whenever a "timing" signal input crosses a user-defined threshold. At the same time, the trigger pulse fires a high-performance sample-and-hold circuit that samples a second "main" signal input.
http://elby-designs.com/contents/en-us/p392.html
Available as an assembled Module and as a DIY project.
This Module is currently available.
$91