| 摘要 |
PURPOSE:To add analog signals of many differential amplifiers by connecting differential amplifiers supplied with input signals and those applied with reference voltages mutually by common load resistances. CONSTITUTION:Couples of transistor (TR) 4 and 5, 6 and 7, and 8 and 9 are provided in such a way that the TRs 4, 6 and 8 on a signal input side and TRs 5, 7 and 9 on a reference power source side are connected to common loads 36 and 37 respectively. Therefore, voltages based upon input signals 1-3 to the TRs on the signal input side are added together to cause a voltage drop across the load resistance 36. Similarly, currents based upon reference voltages 13-15 are added together to cause an added voltage drop across the load resistance 37. On the other hand, resistances 22, 25, 28, and 29 and an operational amplifier 30 constitute an adding and subtracting circuit which inputs (1)s as an addition and a subtraction input and a difference in signal voltage between the load resistances 36 and 37 is found, so that a signal removed from a DC component appears at an output terminal OUT. |
