| 摘要 |
PROBLEM TO BE SOLVED: To obtain a differential amplifier which is a system configuration that does not need an external reset signal by using an average value detection system and keeps the offset cancel amount of a differential input signal constant regardless of presence of the same code continuation and mark rate variation, and to provide an optical receiver. SOLUTION: In the differential amplifier provided with a differential amplifier circuit 17 for amplifying a differential type input signal, and an offset compensating part 16 for performing offset compensation of the input signal, the differential amplifier circuit 17 includes transistor pairs 1 and 2 for amplifying an input signal comprising a positive phase input signal VIP and a reverse phase input signal VIN, and load resistor pairs 3 and 4 connected to a pair of output ends respectively, and the offset compensating part 16 draws out a current corresponding to differential voltage of the average value of one of the positive phase input signal VIP or the reverse phase input signal VIN and an average value detection signal VaveN2 obtained by inverting the other average value with predetermined reference voltage Vref from a current made to flow to the load resistor pairs 3 and 4. COPYRIGHT: (C)2011,JPO&INPIT
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