| 摘要 |
PROBLEM TO BE SOLVED: To make the operation of the receiver stable with high accuracy by providing plural peak detection sections with different operating dynamic ranges and different gains to a peak detection circuit and operating any of the plural peak detection sections depending on an input level of an input optical signal. SOLUTION: An AMP 4 compares a voltage around a peak hold capacitor CP with a reference voltage VREF and feeds back its output corresponding to the quantity of the difference to an operational amplifier OP1. Then the PP1 continues outputting a positive logic Q when a data input is logical 1 till the data input and the value fed back from the AMP4 are coincident. While the positive logic Q is being outputted, the capacitor CP is charged, in which a peak value corresponding to the data input is stored. When a reset signal is given to a BUFF, a transistor(TR) 3 is conductive by an output of an AMP 3 and the charges in the capacitor CP are discharged. Thus, the peak hold value is reset and a wide dynamic range processing is implemented. |
