Rapid Increase, Slow Decrease
We've done this for a few customers. The basic application - monitor the peak value of a repetitive signal.
The first application was on an automated machine which formed nail heads. We never saw the machine, but our understanding is that it would "whack" heads on the nails in rapid succession. The user needed to know and control the impact force - not each and every individual impact, but the "normal" or "average" impact. In other words, he needed to know that the machine was properly set.
As the sketch shows, the output rises quickly to the peak value but decays slowly. (Actually, the unit we built had more filtering than is shown in the illustration.) The output of our module smoothed and held the value of the peak impact force.
We've built a few variations on this theme. One had an adjustable decay time (reference - our special feature #X0098) and one had a fixed 3-second time constant (X0214). Right now we're quoting a unit which adds a polarity-insensitive "absolute value" function - both positive and negative peaks will produce a positive output.
Links: Custom & Special Signal Conditioners
Our complete signal conditioner line