Why would varying the pulse width without changing the characteristics of
the pulse transitions (rise/fall) affect the harmonic content of the pulse?
No bandwidth and no harmonics at all are produced by the constant DC level
of the pulse before and after each transition.

Wouldn't the harmonic structure and bandwidth needed to produce/reproduce a
pulse be related only to the rise and fall times of that pulse, and the
transition shapes (sin^2, etc), and be independent of the width (time)
between the transitions?

RF

Visit http://rfry.org for FM broadcast RF system papers.