AN OPTICAL HARMONIC ANALYZER 415 



with the optical analyzer. Each is compared with an analysis of the 

 identical wave form made on a Henrici type analyzer at the State 

 University of lowa.^ The first sound is a portion of the er in 

 father. There is a very prominent fourth harmonic, indicating a 

 strong resonance in the voice at 530 cycles. Other smaller peaks 

 occur at 1400, 2650 and 3500 cycles. The second sound is a portion 

 of the diphthong ou in out. It shows two peaks of about equal 

 magnitude, with a suggestion of a third smaller one. The general 

 features of the analyses by the two methods are seen to be in good 

 agreement. A series of such analyses throughout the course of a 

 spoken sound furnishes a fairly complete description of the changes in 

 resonance, amplitude, and fundamental frequency which are taking 

 place. Because of its high speed of operation and convenient applica- 

 tion to records of speech on film, the present form of the optical 

 analyzer is especially adapted to such a study of the characteristics 

 of connected speech. 



9 "The Henrici Harmonic Analyzer," D. C. Miller, Jour. Franklin Inst., vol. 185, 

 pp. 285-322 (1916). 



