Question: How to plot the envelope of a time-domain response?

In my Maple program, the voltage output of the system is computed as a time-domain response under different time intervals. The response curve has already been successfully obtained and plotted.

However, I would like to further extract and plot the envelope of this response. I initially attempted to determine the envelope by identifying the extrema of the signal, i.e., by solving the condition that the time derivative of the response equals zero. Unfortunately, this approach consistently leads to error messages, and I am not sure whether the issue is related to symbolic differentiation, numerical noise, or the implementation itself.

Could anyone please advise on:

1. The correct way to extract an envelope curve from a time-domain signal in Maple?

2. Whether there are alternative or more robust methods (e.g., based on numerical post-processing, signal processing techniques, or built-in Maple tools) to obtain the envelope, especially for numerically computed responses?

Any suggestions or example commands would be greatly appreciated.

Thank you in advance for your help.
numsolve-1229.mw