This paper presents a new realization of adaptive notch filter based on a cascade of adaptive IIR notch filters using complex coefficient first-order notch filters. The input is multiple real linear chirp signals embedded in a white Gaussian noise. Closed-form expression for frequency tracking mean square error (MSE) is given. Optimum step size parameter and notch bandwidth coefficient that minimize the tracking MSE are also derived. Computer simulation results are presented to validate the analysis.