UI That Accepts Parameters and Generates Plots
Identify the Axes
Since there are two axes in this UI, you must specify which one you want to target
when plotting data. Use the handles structure to access the target axes in your
code. All fields in the handles structure are named according to each object’s Tag
property value. In this case, handles.frequency_axes returns the top axes, and the
handles.time_axes returns the bottom axes.