| 摘要 |
PURPOSE:To compensate the change in the frequency characteristic depending on an AGC voltage VACG by providing the 2nd constant current source having a current change rate in the correlation with the gain control ratio of the 1st constant current source connected to a base of an AGC transistor (TR). CONSTITUTION:The base of the AGC TR 21 is connected to a power supply VCC via a resistor R1 and connected to the collector of the 1st constant current TR 29 via a resistor R2 grounded via a capacitor 44. The emitter of the 1st constant current TR 29 is grounded via a resistor R3 and the base is connected to a control terminal 24 to which the AGC voltage VAGC is fed together with the base of the 2nd constant current TR 35. Further, the emitter of the 2nd constant current TR 35 is grounded via the resistor R3 and the collector is connected to the emitter of the AGC TR 21 grounded via a capacitor 38 via a high frequency choke coil 37.
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