Frequency response modifying appts. for telephone piezoelectric transducer - alters cross=sections of acoustic resonators and apertures for resonance in band between 1.9 and 3 kHz

摘要

A cover (7) is clamped by the metallic housing (2) in the space in front of the transducer plate (3) which comprises a support (4) and a piezoelectric disc (5) having electrodes on both sides. Two concentric contact surfaces (21,22) sepd. by an annular space are formed on the cover for secure fitting into, e.g. a telephone handset. The inner surface (22) is divided into three arcs by gaps serving as coupling apertures for the resonators formed between the surfaces and bounded by radial bars joining them together. ADVANTAGE - Frequency response and attenuating effect of resonators can be influenced within narrow limits.