A Method for the Production of Longitudinal Sound Vibrations in a Rod

In connection with some work being done in the testing of acoustic wave filters in solid media, a method has been developed for the production of longitudinal sound vibrations in a rod. Electrical oscillations are generated in a vacuum tube oscillator, pass through two stages of power amplification, and are used as the input to a special oscillator attached to the end of the rod. This oscillator is similar in principle and construction to the Fessenden oscillator used in submarine sound signaling. Vibrations which have a fair purity of tone, and which have a considerable intensity over a wide range of frequencies are obtained in the rod