332 



BELL SYSTEM TECHNICAL JOURNAL 



hn = 



«7r(l — COS 6/2) 



[ sin (n - 1)6/2 _ sin (w + 1)6/2 "] , . 

 L «- 1 »+ 1 J ^ ^ 



in which A is the amplitude of the pulse and b the pulse width as shown 

 in Fig. 1. 



0.02 — ^^ 



^ 0.006 

 u 0.005 

 J 0.004 

 •^ 0.003 



O 0.002 



20 40 60 80 100 120 140 160 ISC 



HARMONIC NUMBER (n) 



Fig. 1 — ^Harmonic content of a wave consisting of sinusoidal pulses 



< 0.02 



i 0.008 



I 0.006 

 uj 0.005 



O 0.002 



20 40 60 80 100 120 140 160 180 200 



HARMONIC NUMBER (n) 



Fig. 2 — Harmonic content of a wave consisting of rectangular pulses 



The form of this expression immediately suggests that for some harmonics 

 the terms 



sin (w - 1)6/2 _ sin (« + 1)6/2 

 « — 1 » + 1 



may become equal to zero causing these harmonics to vanish. That this 



