| 摘要 |
PURPOSE:To prevent the generation of the hawling of a handset that uses a vibra- tion pickup type ear microphone available for a talk with a single ear, by providing a correcting device that cancels the output voltage of a receiver. CONSTITUTION:Correcting device 5 has vibration pickup 6 with nearly the same frequency characteristics that sound vibrating pickup 2 of vibration pickup type ear microphone 1 has. Then, both pickups 2 and 6 are arranged at acoustically-equal intervals to receiver 4 via waveguides 7 and also connected to each other so that both outputs will cancel. Therefore, a voltage developed by ear microphone 1 never reaches transmitter 9, and consequently the generation of hawling can be prevented. As a result, the volume of the receiver can be increased and even under noisy conditions, clear sound reception can be attained. |
