| 摘要 |
<p>A detector for an automatic gain control amplifier circuit comprising a full wave rectifier circuit (122), a differential circuit (123), a smoothing circuit (127), a variable resistor and a control voltage source (113). The full wave rectifier circuit (122) includes, first, second and third transistors having a common bias voltage applied to the bases thereof. An input signal (V1,V2) is applied to the base of the first transistor (101) and a complementary signal to the base of the third transistor (103). A first current source (111) is connected in common to the emitters of the three transistors. In the differential circuit (123) there are fourth (105) and fifth (106) transistors having bases between which a control voltage from the control voltage source (113) and variable resistor (150) is applied. A current from a second current source (112) is supplied to the fourth and fifth transistors. A first load is connected in common to collectors of the first and fourth transistors and a second load is connected in common to the collectors of the second, third and fifth transistors. First and second outputs are derived from respective first and second loads. <IMAGE></p> |
