Abstracts of Technical Articles by Bell System Authors (01 January 1947)

Depends upon the frequency, the intensity and the overtone structure of the sound wave transmitting the tone. Similar relations are also given which show how the loudness and the quality depend upon these same three physical characteristics of the sound wave. These relationships were demonstrated by using the new Tone Synthesizer. 

By means of this instrument one is able to imitate the quality, pitch and intensity of any musical tone and also to produce many combinations which are not now used in music. The Sound Spectrograph.6 W . KOENIG, H . K . DUNN, AND L . Y . LACY. The sound spectrograph is a wave analyzer which produces a permanent visual record showing the distribution of energy in both frequency and time. This paper describes the operation of this device, and shows the mechanical arrangements and the electrical circuits in a particular model. Some of the problems encountered in this type of analysis are discussed, particularly those arising from the necessity for handling and portraying a wide range of component levels in a complex wave such as speech. 

Spectrograms are shown for a wide variety of sounds, including voice sounds, animal and bird sounds, music, frequency modulations, and miscellaneous familiar sounds. Geometrical Characterizations of Some Families of Dynamical Trajectories.6 L . A . MACCOLL. A broad problem in differential geometry is that of characterizing, by a set of geometrical properties, the family of curves which is defined by a given system of differential equations, of a more or less special form.