| 摘要 |
PURPOSE:To suppress the thermal distortion due to a voltage change in the base-emitter voltage separating the signal line into a high frequency signal line and a low frequency signal line provided with a feedback circuit comprising an operational amplifier between the base and emitter of a transistor(TR) of common emitter connection. CONSTITUTION:A differential input signal given to input terminals 1, 11 is impressed to common emitter TR pairs 15, 16 via Zener diode pairs 3, 12 for level shift. Since the amplifier stage is connected between emitters via a capacitor 14, the DC component is cut off and only the differential signal component of a high frequency is amplified and sent through common base TR pairs 17, 18 of cascode constitution and a differential output of high frequency is obtained at output terminal pairs 19, 20. The low frequency component is fed to a noninverting input of operational amplifier pairs 2, 10, recovered at the emitters of the TR pairs 5, 9 and a differential signal is amplified via an emitter coupled resistor 6.
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