| 摘要 |
790,932. Transistor oscillator circuits; keying carrier frequencies. GENERAL ELECTRIC CO. July 27, 1955 [July 27, 1954], No. 21724/55. Classes 40 (5) and 40 (6). An oscillator comprises a number of base input transistor stages connected in cascade, a fixed inductance connected between the input electrode and common electrode of the first transistor, a variable positive feedback path from a later stage to the input of the first stage and variable resistances connected between at least some of the transistor electrodes and their supply leads, the arrangement being such that by varying the resistances and the feedback the frequency and waveform of the oscillations may be varied. Fig. 1 shows three common emitter stages connected in cascade with a variable feedback resistor 29 connected to an inductance 16 in the input circuit of the first transistor. With slight feedback the output oscillations can be of sinusoidal form but by varying the resistances and feedback the waveform may be squared as a result of limiting in the transistors. Further adjustment can produce a sawtooth output wave while still further adjustment can produce interrupted oscillatory waves such as are shown in Figs. 3 and 6. To produce these the property of a transistor that it produces a non-phase-reversed signal at its output when the input potential exceeds the collector potential is used.
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