| 摘要 |
PURPOSE:To attain sure transmission of a voice signal with excellent privacy call without radio interference by retransmitting an optical signal when an optical axis deviation detecting means detects deviation of the optical axis at optical transmission in communicating mobile bodies with the optical signal. CONSTITUTION:In transmitting voice information from a car body CT1 to a car body CR1, a specific ID code IDR decided to the car body CR1 is set by the car body CT1 and the IDR is irradiated toward the car body CR1 through optical transmission. After the reception of the IDR, the CR1 superimposes the IDR on a focus beam O2 to irradiate the IDR of the CR1. The car body CT1 receives the focus beam O2, and when the code IDR is coincident with the irradiated code IDR before and the optical axes are coincident while the detected level is a prescribed value or over, the voice signal is converted to the transmission optical beam O1 and transmitted momentarily while being subject to time compression. When the CR1 receives the compressed voice signal, the time axis is expanded as it is. When the CT1 cannot receive the IDR, it is discriminated as the deviation of optical axes and the IDR is transmitted again. Since the information is transmitted by compressed voice, the correspondence is not disturbed even if temporary interruption of the optical axis deviation takes place because of ups/downs of a road. |
