| 摘要 |
PURPOSE:To reduce even-order harmonic components to reduce the overall harmonic distortion by using the whole of a signal transmission line for optical negative feedback. CONSTITUTION:The output signal of an amplifying circuit 1a is inputted to a light emitting diode 1b, and an obtained optical signal is inputted to a photo diode 3b through an optical fiber 2, and the output signal drives an electroacoustic transducer 5 through an amplifying circuit 3a and a power amplifying circuit 4. The output signal is inputted to a light emitting diode 6b after amplified by an amplifying circuit 6a. The optical signal is inputted to a photo diode 8b through an optical fiber 7, and the output signal is inputted to an analog signal direct light intensity modulating circuit 1 after having the level adjusted by an amplifying circuit 8a. Since a single negative feedback circuit exists between the input and the output of the amplifying circuit as the whole, even-order harmonic components due to the approximate square characteristic of light emitting diodes and those in the power amplifying circuit are reduced.
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