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不太久以前,低噪声接收机还使用小型平面陶瓷三极管。凡是在三极管和半导体器件竞争的地方,栅控三极管都已为低噪声晶体管或场效应管所代替。最近,在VHF/UHF频率范围,晶体双极器件和场效应器件获得了较高水平的连续波功率输出,其效率可与三极管相比拟。雪崩二极管和体效应二极管,已在更高的微波频率上起到本振的作用,而速调管和磁控管仍将继续保持单管输出功率最高的地位。除去这些失势之外,平面陶瓷三极管在如下微波领域仍然占据一些“要塞”:
Not too long ago, low noise receivers also used small flat ceramic transistors. Where the triode and semiconductor devices in competition, gated transistors have been replaced by low-noise transistors or FETs. Recently, crystal bipolar devices and field effect devices have achieved higher levels of continuous-wave power output in the VHF / UHF frequency range, comparable in efficiency to triodes. Avalanche diodes and bulk effect diodes have been used as local oscillators at higher microwave frequencies, while klystrons and magnetrons will continue to have the highest single-tube output power. In addition to these losses, the planar ceramic transistor still occupies some “fortresses” in the following microwave areas: