函數(shù)信號(hào)發(fā)生器設(shè)計(jì)外文資料及翻譯(已修改)
2025-01-28 10:36 本頁(yè)面
【正文】 函數(shù)信號(hào)發(fā)生器設(shè)計(jì)外文資料及翻譯英文資料原文WAVEFORM GENERATORS Basic Priciple of Sinusoidal Oscillators Many different circuit configurations deliver an essentially sinusoidal output waveform even without inputsignal excitation. The basic principles governing all these oscillators are investigated. In addition to determining the conditions required for oscillation to take place, the frequency and amplitude stability are also studied. show an amplifier, a feedback network, and an input mixing circuit not yet connected to form a closed loop. The amplifier provides an output signal as a consequence of the signal applied directly to the amplifier input terminal. The output of the feedback network is and the output lf the mixing circuit (which is now simply an inverter) is Form the loop gain is Loop gain= An amplifier with transfer gain A and feedback network F not yet connected to form a closed loop.Suppose it should happen that matters are adjusted in such a way that the signalis identically equal to the externally applied input signal. Since the amplifier has no means of distinguishing the source of the input signal applied to it, it would appear that, if the external source were removed and if terminal 2 were connected to terminal 1, the amplifier would continue to provide the same output signal as before. Note, of course, that the statement =means that the instantaneous values of andare exactly equal at all times. The condition=is equivalent to, or the loop gain must equal unity. The Barkhausen Criterion We assume in this discussion of oscillators that the entire circuit operates linearly and that the amplifier or feedback network or both contain reactive elements. Under such circumstances, the only periodic waveform which will preserve, its form is the sinusoid. For a sinusoidal waveform the conditionis equivalent to the condition that the amplitude, phase, and frequency ofandbe identical. Since the phase shift introduced in a signal in being transmitted through a reactive network is invariably a function of the frequency, we have th
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