| 摘要 |
PURPOSE:To obtain an information transmission means giving information inherent to a community in a limited range by providing a traffic signal lamp with a modulator circuit and a signal lamp drive circuit, modulating outputted light from a signal lamp with the aid of input data and transmitting information to vehicles through space optical communications. CONSTITUTION:The modulator circuit 2 makes a sound signal inputted to a signal input terminal 1 into a modulation signal, which enters the signal lamp drive circuit 3, drives a traffic signal lamp 4 and is converted into an optical signal. It is transmitted to a light receiving part 6 fitted on the upper part of a vehicle 4, converted into an electrical signal by a light receiving element 7 and amplified by an amplifier 8. Then a demodulator circuit 9 demodulates said signal to attain its original sound signal. A sound amplifier circuit 10 amplifies said sound signal, and drives a speaker 11, whereby a driver can hear information outputted by sound. If a modulation frequency is higher to some extent, the driver never considers said frequency as flicker, and therefore there is no trouble in terms of traffic safety. |
