Acoustic transmitter with membrane with adjustment screw forming one side of enclosure

摘要

The transmitter has a membrane (1) which forms part of the boundary (2) of the enclosure in which the transmitter is located. On one side it can be excited to oscillate by acoustic waves in the enclosure medium. A cover plate (3) has a duct, which does not assume the temperature of the enclosure medium (4), projecting at 90 deg. to the membrane surface. The resonant frequency of the membrane fR is at least the size of the exciting frequency fS. Between membrane and cover plate is a gap of some tenths of a mm. Only the edge region of the membrane or the enclosure boundary outside the membrane and the cover plate are in sealed contact. The duct with a cross section QK, smaller than the membrane surface QM, leads to an acoustic receiver. A screw (6) projects into the duct and is fixed at 90 deg. to the membrane surface with a gap of some tenths of a mm. between bolt and inner wall of the duct.