| 摘要 |
PURPOSE:To prevent a whisker from being generated in an output signal at the time of separating two signals at a photoreceiving side by transmitting the signal and a clock simultaneously. CONSTITUTION:A counter 11 counts the clock and frequency-divides it into 1/2. AND gates 12a and 12b, an inverter 14 and an OR gate 13 output input (1) and (2) by the output signal of the counter 11 by switching alternately. A light emitting element 21 emits light by receiving the supply of constant currents I0 and 2I0 from constant current sources 22 and 23, respectively by TRs 17 and 18, however, it outputs an optical signal with four values by being driven by a current with four values 0, I0, 2I0 and (I0+2I0) corresponding to the output signal of the OR gate 13, which is passed through the AND gate 12a and 12b, and the output signal of the counter 11. Since the optical signal is the one having almost equal adjacent intensifying level difference, and also, the clock is multiplexed on the signal, it is possible to easily generate the clock at a reception side, and to prevent the whisker from being generated in the output signal at the time of reproducing the signal. |
