All-pole phase-locked tracking filters

This paper describes the design and synthesis of second-, third-, and fourth-order all-pole, phase-locked tracking filters for those applications in which the signal-to-noise ratio is large. Higher order transfer functions are also realizable as a cascade of these basic structures. Using cataloged analog filter data allows the phase-locked loop to be designed so that its transfer function and associated responses duplicate tabulated filter responses. Phase-locked loop parameters for seven classical filter responses have been tabulated. Also included are discussions of acquisition, open-loop characteristics, phase margin, error signal, noise bandwidth, and loop-filter realizations. Finally, an example illustrates the introduced procedures.