| 摘要 |
<p>PURPOSE:To prevent a wrong switching action with the vibration signal passed through the tissue of bones of the wearer himself of a vibration pickup type ear microphone, by securing the signal that gives a switching control to a transmitter/ receiver that performs a transmission and recording by means of the said ear microphone. CONSTITUTION:In the transmission system A, the aural signal sent from the vibration pickup type microphone 1 is transmitted or recorded through the transmission main circuit 2 after amplified by the amplifier 3. On the other hand, in the reception system B, the transmission signal sent from outside is received at the reception main circuit 7 and then amplified through the amplifier 8 to be converted into the sound wave by the air conduction type speaker 10. For the microphone 1, the vibration generated through the impact of teeth between the upper and lower jaws and when the microphone wearer closes his jaws has a higher level than the bone transmission signal of the voice in the frequency band less than 200Hz. This vibration signal is detected by the filter 5, and then the automatic switch controller 6 is actuated to turn on the transmission/ reception switch circuit 9. Thus the circuit 2 is opened. The transmission can be controlled and stopped by generating a sound of vibration with clenching the teeth of the microphone wearer.</p> |
