Comment: A note on determination of oscillation startup condition

Abstract

The comment is related to the recently published papers given in [Singh, V. (2006). Analog Integrated Circuits and Signal Processing, 48, 251-255;Singh, V. (2007). Analog Integrated Circuits and Signal Processing, 50, 127-132.] which depict the failure of Barkhausen oscillation building up criterion. Many counterexamples have been given in order to substantiate such viewpoint. We would like to review these reported circuit examples and present the treatment of Barkhausen oscillation criterion.

Identification of a class of two CFOA-based sinusoidal RC oscillators

“…It appears, therefore, that the conditions of oscillation startup stated as e 0 = 0, and obtained using the Barkhausen criterion, are not sufficient to startup and maintain oscillation. In fact the validity of the Barkhausen criterion in determining the startup condition of oscillation has been recently challenged [13][14][15][16][17] and its failure to determine the startup and building of oscillation has been reported. Thus, it is essential to revisit Eq.…”

“…On the other hand, the condition of startup and the frequency of oscillation of the circuits proposed in [1][2][3][4][5][6][7][8][9][10][11] are obtained by applying the Barkhausen criterion. Recently the use of this criterion for determination of the startup condition of oscillation has been challenged [13][14][15][16][17] and its failure has been reported. In fact in [10,11] the author noted that the startup of oscillation is achieved only when the values of the passive components deviate from the condition imposed by this criterion.…”

Discussion on the general oscillation startup condition and the Barkhausen criterion

“…This situation is also explained in [3]. The relation of the Barkhausen criterion and the general oscillation condition can be explained by the feedback network theory.…”

“…Recently, several articles have been written showing the Barkhausen criterion as the determination of oscillation startup condition for a harmonic oscillator [1][2][3]. In those articles, some examples and the application of the Barkhausen criterion are reviewed.…”

Discussion on Barkhausen and Nyquist stability criteria

“…Given an oscillator circuit, one needs to determine the condition of oscillation and the frequency of oscillation therein. This paper specifically refers to the Barkhausen criterion for the determination of oscillations, which is described in most textbooks [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and which has been the subjet of recent discussions [20][21][22][23]. In [20,21], some examples in which the Barkhausen criterion fails to produce the correct condition for startup of oscillations have been reported.…”