| 摘要 |
<p>1,061,301. Amplifiers with negative feedback. SIEMENS & HALSKE A.G. Jan. 7, 1966 [Jan. 8, 1965], No. 748/66. Heading H3W. In a high-frequency amplifier amplifying signals having a frequency f, in which a negative feedback circuit is connected between output and input, distortion is reduced by connecting across the input a parallel tuned circuit Lg, Cg resonant at a frequency f 0 such that it presents an inductive reactance at the signal frequency f. The amplifier operates into a load 2 such as an aerial and the feedback network as shown comprises a capacity potentiometer 3, 4 and series resistor R 2 . It is stated in the Specification that (1) particularly favourable results are obtained if the condition is satisfied, and (2) the impedance Ri of the signal source U 0 and the total effective parallel resistance Rg of the tuned circuit should be in a ratio greater than that 1: 100. In covering a wide tuning range, the value of the inductance Lg may be altered stepwise so as to maintain the distortion at a minimum over the range. The arrangement is stated to be particularly suitable for use in single sideband short wave transmitters.</p> |
