| 摘要 |
1,065,415. Transistor amplifier circuits. RADIO CORPORATION OF AMERICA. April 6, 1964 [April 19, 1963], No. 14107/64. Heading H3T. Cross modulation with interfering signals in a gain controlled insulated gate field effect transistor amplifier is reduced by connecting the drain of the transistor to the source electrode of a further similar transistor, for example to form the cascode amplifier shown, and by applying the automatic gain control signal to the input transistor in such a polarity as to increase the current flow as the signal amplitude increases. The field effect transistors of the radio receiver shown have their substrates 88, 90 earthed and a further gain control signal is applied to the gate 82 of the second transistor in such a sense as to tend to reduce the current as the signal increases. This second signal may be delayed with respect to the first. In Fig. 5 (not shown) the second transistor 90 is not gain controlled, its gate 82 being connected through a resistor to the common connection 84 between the transistors. |
