| 摘要 |
PURPOSE:To suppress the deterioration of S/N that is caused by distribution of optical signals by using a time-division optical distributor which samples the input optical signals every prescribed period and distributes these sampled optical signals and an optical receiver which detects the distributed optical signals. CONSTITUTION:The pulse voltage V given from a pulse generator PG is impressed directly to an optical switch SW1 of the 1st stage and also to optical switches SW2 and SW3 of the 2nd stage via a pi/2 delay line DL respectively. Thus an analog optical input signal Ii is distributed to four time-division signals I1'-I4' and supplied to optical receivers RCV1-RCV4. The RCV1-RCV4 is provided with a photodetector D, an amplifier A, LPF1 and 2, an S/H circuit which selects properly the sampling optical signals and gives interpolation to a part where no optical signal exists by an electric signal, and a timing circuit C. A switch is carried out between the sampling state and the holding state when the PAM signal shows its peak value. Therefore output signals I1''-I4'' having output levels close to the signal Ii is obtained by controlling the pulse width and the phase of the circuit C. Then an analog signal I0 having a high S/N is demodulated by the LPF2. |
