| 摘要 |
PURPOSE:To discriminate signal lights definitely from noise lights and to remove extraneous noise lights without fail, by subjecting the signal lights to burst modulation by using a high frequency and a low frequency. CONSTITUTION:A frequency from an oscillating circuit OSC is divided by a frequency division circuit FD1. A frequency obtained from the frequency division circuit FD1 is further divided by a frequency division circuit FD2. The output of the frequency division circuit FD1 and that of the frequency division circuit FD2 are inputted in a modulation circuit MC and synthesized through burst modulation. The output of the modulation circuit MC is inputted in a driving circuit DRV and thereby a light-emitting element LED is driven. A signal light SL is obtained from the light-emitting element LED. |
