NOISE PREVENTING TYPE TRANSMITTER

摘要

PURPOSE:To obtain a proper and sure noise preventing function by piercing small holes leading the sound pressure at a low frequency band due to surrounding noise into a diaphragm rear chamber in addition to damping holes to the rear face of a piezoelectric ceramic type transmitter so as to introduce the noise sound pressure at the low frequency band where the talking voice is easily unclear especially from the front face and rear face of the diaphragm thereby cancelling it. CONSTITUTION:The sound pressure at a low frequency band being problem to ensure especially the taking quality in the sound pressure caused by surrounding noise from various sound sources at a remote position parted from the transmitter 1 is led into an enclosure 10 from a mouthpiece 10a provided to the transmitter-receiver enclosure 10 and vent holes 21 for introducing sound pressure as shown in broken lines and acts onto the front face and the rear face of a diaphragm 3 via front bent holes 5a of the front cover 5 and small holes 20 as differential vent holes. In this case, the sound pressure acting onto both sides of the diaphragm 3 has no different phase because the distance between the sound source and the diaphragm 3 is remote and has almost no difference, the sound pressure has similar levels, then both the sound pressure are cancelled together at both sides of the diaphragm 3.