| 摘要 |
PURPOSE:To expand a dynamic range by eliminating the deterioration in a duty ratio at the most leading part of a burst signal. CONSTITUTION:An optical burst signal is received and an optical current iP is obtaimd by a photodetector 1. The optical current iP is inputted to a voltage current conversion section 2 to be a signal (a), and by passing through an AC coupling capacitor 3, a signal (b) is obtained, The signal (b) is inputted to a peak holding circuit 4, from which a signal (c) is obtained and it is inputted to a voltage dividing circuit 5 provided with a peaking capacitor, from which a signal (d) is obtained. Then the signals (b), (d) are inputted to a differetial amplifier section 7, from which a signal (e) is obtained. It is inputted to a comparator 8, from which a digital sigital signal is obtained. |
