| 摘要 |
<p>PURPOSE:To monitor transmitting states of channels and to simultaneously realize control of a transmitting modulation index, etc., by feeding back a control signal oscillating frequency interval responsive to an error between the central frequency of a beat signal to be obtained by a photodetector and a predetermined frequency to a corresponding light source of a plurality of light sources to be controlled. CONSTITUTION:An output of a heterodyne receiver 50 is a beat signal of the output of a light source l and the output of a transmitting light source 40. The part of the signal is input to an IF frequency discriminator 60 formed of a delay detector, an error signal between a set IF central frequency and the central frequency of the input beam signal is output, and fed back to a corresponding light source l of a light source group 20 by 1X16 first switching circuit 80. When the stabilization is finished, its information is input to a controller 44, the oscillation frequency of the source 40 is altered to next frequency, and a light source 2 is similarly stabilized. This is repeated to stabilize the sources of the group 20 from the corresponding transmitted peak of a Fabry- Perot resonator 41 to a position deviated by a set IF frequency.</p> |
