| 摘要 |
<P>PROBLEM TO BE SOLVED: To enhance durability of a quantity of light variable means in an optical space communication device. <P>SOLUTION: At S1, a diaphragm for adjusting the quantity of light is set not to limit the quantity of light. At S2, reception light passed through the diaphragm for adjusting the quantity of light is converted through a light-receiving element into a voltage signal V1. At S3, reception light is converted through a light-receiving element into a voltage signal V2. At S4, a voltage signal V3 is obtained by limiting only the component of high-frequency zone, and a voltage signal V4 is obtained by reversing the phase at S5. At S6, a voltage signal V5 is obtained by adding the signals V1 and V4. At S7, a decision is made whether the signal V5 is above a specified lower limit or not, and the control goes to S8 if the signal V5 is above the lower limit. Otherwise, it goes to S9. At S9, the quantity for limiting the quantity of received light passing through the diaphragm for adjusting the quantity of light is reduced. At S8, a decision is made whether the signal V5 is below a specified upper limit or not, and the control goes to S10 if the signal V5 is below the upper limit. Otherwise, it goes to S11. At S10, the quantity for limiting the quantity of received light passing through the diaphragm for adjusting the quantity of light is not changed, and the quantity of light passing through the diaphragm for adjusting the quantity of light is increased at S11. <P>COPYRIGHT: (C)2009,JPO&INPIT |
