A study on linear single-loop feedback systems using geometric vectors

An analysis method based on vector triangle and vector locus is introduced in this paper. By using vector triangles, a set of quantities generally used in feedback theory can be intuitively visualized, which is impossible by using other theories. The vector locus records the evolvement of the vector triangle versus frequency in polar coordinates, and combines the magnitude and phase plot together in one track. Examples are given to show that the proposed method gives intuitive insights while still retains a general method to characterize feedback systems.