| 摘要 |
PURPOSE:To prevent momentary breaks of optical output to a transmission line by extending the pulse width of a request signal, which requests an optical transmitter to output light beams, to delay change from the turning-on state to the turning-off state and stopping the output of the current optical transmitter after output of light beams from a stand-by optical transmitter. CONSTITUTION:A switching control signal 9 is branched into two, and one is inputted to a pulse width extending circuit 5 and has the pulse width extended to delay the change from the (H) level to the (L) level of the request signal, which requests an optical transmitter 1 to output light beams, and is inputted to the optical transmitter 1. The other has the logic inverted by an inverting circuit 4 and is inputted to a pulse width extending circuit 6 and has the pulse width extended to delay the change from the (H) level to the (L) level of the request signal, which requests an optical transmitter 2 to output light beams, and is inputted to the optical transmitter 2. Thus, light beams output of the optical transmitter 1 and that of the optical transmitter 2 overlap. |
