| 摘要 |
PURPOSE:To allow an optical reception section to easily extract a timing clock without use of a surface acoustic wave resonator by applying an integral number of multiple of multiplication or frequency division to a clock signal, adding a clock signal component to a digital information signal at a transmission section and sending the result. CONSTITUTION:An optical transmission section 1 is provided with a multiplier circuit 3 multiplying a 1st clock signal fo synchronized with a digital information signal with a multiple of (n), an adder circuit 4 adding a clock signal 2fo and the digital information signal and a semiconductor laser 5 converting its output into an optical signal. An optical reception section 2 is provided with an optical detector 7 converting an optical signal from the optical transmission section 1 into an electric signal, a separating circuit 9 separating the electric signal into digital information signal and a clock signal 2fo, and a frequency divider circuit 10 frequency-dividing the obtained clock signal 2fo by 1/n and reproducing the 1st clock signal fo and uses the clock signal fo to make an identification circuit 13 identify the digital information signal. Thus, no waveform distortion exists in the information signal, the deterioration in the reception sensitivity is avoided and the clock signal is recovered without a surface acoustic wave resonator. |
