| 摘要 |
PURPOSE:To suppress noises by eliminating mode filter effect by diffusing the light-emission spectrum of a laster diode by the higher-harmonic components of a pilot signal or the rectangular wave output of a carrier oscillator for audio modulation. CONSTITUTION:A video input signal is amplified by a video amplifier 7 and also applied to a laser diode driving circuit 2 together with a modulation output, obtained by modulating the rectangular wave signal of a carrier oscillator 8 for audio modulation by an audio signal or pilot signal, to turn on a laser diode 3, performing conversion to a light output 6. Part of the light output is converted by a pin photodiode 4 into an electric signal, which is fed back to the driving circuit 2 through a light-emission-output stabilizing circuit 5. The light emission spectrum of the laser diode 3 is diffused by higher-hamonic waves of the rectangular wave of the oscillator 8, so mode noises are suppressed. |
