| 摘要 |
<p>D-22,794 VARIOLOSSER FOR AN AUTOMATIC GAIN CONTROL CIRCUIT by Tom L. Blackburn A dc control current is developed in a first transistor circuit and the control current is responsive to a control voltage which is proportional to the output voltage of a fixed gain amplifier. A reference voltage is applied to a second transistor which provides the normal operating bias for said fixed gain amplifier, and, also, provides a variable impedance via the diode circuit of the base-emitter junction. This diode circuit is a part of a variolossor that also includes a resistor which is connected in the series path between the signal source and the fixed gain amplifier. The bias voltage of the second transistor does not change but the diode impedance varies as the control voltage varies so as to maintain the amplifier output constant.</p> |
