An oscillator can be viewed as a positive feedback system, with a forward gain stage A and a feedback network beta. If the forward gain stage has a gain of 10 with a phase shift of Phi, specify the S parameters for the feedback stage beta to ensure oscillation. Assume that the amplifier output is connected to the feedback port 1 and the feedback port 2 is connected to the amplifier input. Express the S parameters as a matrix. Assume the feedback element is ideal. Solution gain = A/(1+AB) for the oscillator no oscillation, magnitude(AB) =1 angle A1 + angle B1 = 180.