| 摘要 |
The transmission curve of an AM modulator for high-power broadcasting stations, which operates as an audio-frequency push-pull amplifier for high power with two amplifier tubes, is linearised. The characteristic curve of each tube (VI) is divided into a plurality of ranges, and approximated in each partial range by a straight line section, the gradient of the individual sections corresponding to the average slope for each tube (VI) in the appropriate partial range. A DC amplifier (A1), the gain of which is inversely proportional to the approximated tube characteristic curve in the corresponding partial sections, is then connected in series upstream of the tube (VI). In this way, the whole transmission curve is linearised to a large extent by the amplifier (A1) plus the tube (VI), and the zero signal current is reduced to virtually zero. <IMAGE>
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