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BELL SYSTEM TECHNICAL JOURNAL 



pressure and also with the distance from the sound source. The 

 solution also gives the magnitudes of the waves of sum and difference 

 frequencies generated when two tones are simultaneously impressed 



2.0 

 1.9 



1.8 

 1.7 

 1.6 

 1.5 

 1.4 

 1.3 

 1.2 

 1.1 

 1.0 

 0.9 

 0.8 

 0.7 

 0.6 

 0.5 

 0.4 

 0.3 

 0.2 

 0.1 



A106 



<'' i.n 



400 600 800 1000 1200 



V=^= SPECIFIC VOLUME IN CM^ PER GRAM 



Fig. la — Adiabatic curve for air. 



on the air; these magnitudes also increase with distance from the 

 source and with the product of the fundamental pressures and, re- 

 spectively, with the sum and difference frequencies. 



