函數(shù)信號(hào)發(fā)生器設(shè)計(jì)外文資料及翻譯-其他專業(yè)-文庫吧資料
2025-01-27 07:44本頁面
【正文】 uch a contingency there is the possibility of simultaneous oscillations at several frequencies or an oscillation at a single one of the allowed frequencies. The condition given above determines the frequency, provided that the circuit will oscillate ta all. Another condition which must clearly be met is that the magnitude of iX and 39。fX = iX is equivalent to 1??AF , 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 work 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 condition 39。fX = iX means that the instantaneous values of 39。 An amplifier with transfer gain A and feedback work F not yet connected to form a closed loop. Suppose it should happen that matters are adjusted in such a way that the signal 39。 1 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 work, and an input mixing circuit not yet connected to form a closed loop. The amplifier provides an output signal oX as a consequence of the signal iX applied directly to the amplifier input terminal. The output of the feedback work is iOf AFXFXX ?? and the output lf the mixing circuit (which is now simply an inverter) is iff AFXXX ????39。 Form the loop gain is Loop gain= FAXXXX i fif ????39。fX is identically equal to the externally applied input signal iX . 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 oX as before. Note, of course, that the statement 39。fX and iX are exactly equal at all times. The 2 c
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