358 BELL SYSTEM TECHNICAL JOURNAL 



sponding to the characteristic region of high pitch are much less 

 intense than those of low pitch. For the other vowels the Intensities 

 of both regions are about alike. 



Oscillograms of the Unvoiced Continuants 



Now let us examine more closely the wave forms for the fricative 

 sounds, s, sh, f, th. They are shown in Fig. 11. These show only 



5H 



^M 



TH 



Wir .V... 1 S. M . i- r ™ £i — 



F 



I I I I I I 



.5 1 



s 



.5 1 



Fig. 11 — Oscillograms of fricative consonants. 



part of the oscillogram produced when each of these sounds was 

 continued for about one second. It is seen that these sounds contain 

 components having high pitches mostly above +1. It is seen that 

 they do not have the wave form repeated as uniformly as was the case 

 with the vowel sounds. They seem to be composed of a series of 

 explosions. For example, the oscillogram for "sh" looks very much 

 like one obtained from the sound of a sky rocket. 



The f and th sounds are magnified six times in amplitude compared 

 to the sh and s sounds. Although much fainter they still show this 

 explosive character. There are 40, 45, 37 and 55 waves per each .01 

 second interval, respectively, for these four sounds corresponding to 

 4000, 4500, 3700, 5500 cycles per second. 



