tri 2 saw modualtion

[Don Tillman]

   Date: Mon, 27 Oct 1997 15:33:48 -0500 (EST)
   From: Eli Brandt <eli at gs160.sp.cs.cmu.edu>

   Don Tillman wrote:
   > A Bessel function describes the amount of each harmonic.
   > 
   > (This is a guess from the harmonic spectra of a PWM square wave -- I
   > haven't done the actual math.  The same mechanism applies though.)

   A triangle-saw sweep is the integral of a square-pulse sweep (if all
   of your pulse waves have the DC properly stripped out), so the nulls
   are in the same place and all.  But the spectrum is tilted 6dB/oct.

Yes, that seems right.

   Do you know how to analyze a PWM sweep? 

It's not easy.

You can find an analysis in most communications electronics textbooks,
in the chapter on FM modulation, because it's the same process you
need to analyze the sprectra of FM.  The book I learned from is
_Introduction to Communication Systems_ by Ferrel Stremler.

  -- Don