| 摘要 |
1,178,039. Negative feedback amplifying Circuits. SIEMENS A.G. 26 July, 1967 [27 July, 1966], No. 34206/67. Heading H3T. An amplifier is provided with a first negative feedback path comprising a two-terminal network # s in series with both the input and output circuits of the amplifier, and a second negative feedback path comprising a T-network # 1 , # 2 , # p connected in parallel with both input and output circuits of the amplifier. It is shown in the Specification that if the series arms # 1 , # 2 of the T-network are resistive and the shunt arm # p reactive, while the two terminal network # s comprises resistance and reactance in parallel, then by retaining relationships between these resistances and reactances which are laid down, either (1) with an arbitrary real output load impedance Za the input impedance W E of the amplifier can be made real; or alternatively (2) with an arbitrary real source impedance R g the output impedance W A of the amplifier can be made real. An amplifier stage of the first type may be followed by one of the second type by the interpostion of a buffer stage which may comprise a grounded-emitter transistor stage with negative feedback (Fig. 3, not shown). |
