Single point contact acoustic transmitter

The invention is an acoustic transmitter (301, 401) that imparts vibratory stresses onto a signal propagation medium such as oil well tubing when actuated by an electric driver. In one embodiment, the acoustic transmitter (301, 401) utilizes a mechanical driver that includes piezoelectric elements (304) to generate the vibratory stresses. The acoustic transmitter (301, 401) is mechanically attached at only one point to the signal propagation medium. This single point attachment eliminates loading on the acoustic transmitter (301, 401) from compressive and tensile forces carried by the signal propagation medium. A mass (406) backing the mechanical driver may be used to extend the frequency range over which the acoustic transmitter (301, 401) is operable. In addition, the resonance response of the acoustic transmitter (301, 401) may be minimized by the use of a viscous dampener (409).; The viscous dampener (409) is configured to "couple" with the mechanical driver when the acoustic transmitter is operating and to "uncouple" with the mechanical driver at other times.