OPTICAL DIGITAL SIGNAL RECEIVING DEVICE

PROBLEM TO BE SOLVED: To receive plural signals whose transmitting rates are different by a single filter in an optical digital signal receiving device for operating signal reproduction by receiving an optical signal in an NRZ(non-return to zero) system or an RZ(return to zero) system at different transmitting rates, and converting it into an electric signal. SOLUTION: A pulse generating means 1 generates a pulse whose pulse width is the half value of a clock cycle in a signal at the highest rate transmitting rate to be received at the changing point of a converted electric signal. A filter 2 outputs the clock frequency components of a signal at the highest rate transmitting rate included in this generated pulse. A pulse converting means 3 converts a sine wave signal outputted from the filter 2 into a pulse signal. A clock cycle converting means 4 coverts the cycle of the pulse signal outputted from the pulse converting means 3 into the clock cycle of the signal to be reproduced. A signal reproducing means 5 reproduces the converted electric signal based on an output clock signal from the clock frequency converting means 4.