| 摘要 |
PURPOSE:To prevent any error from being caused in a digital main signal by devising the transmitter such that a peak of an output of a level stabilizing amplifier is suppressed and a modulator of a light emitting element drive circuit 1 is not over-modulated. CONSTITUTION:An analog sub signal is controlled and stabilized to a prescribed level by a level stabilizing amplifier 31 of a modulation stable circuit 3 and the result is fed to the light emitting element drive circuit 1. An input discrimination circuit 33 discriminates the presence of an input, a gain controller 32 uses the discrimination signal to control an output level of the level stabilizing amplifier 31 thereby suppressing a peak caused the moment when an input of the analog, sub signal changes from the absence into the presence. |
