Design and prototype a phase-lock loop circuit board

This project entails design, simulation, layout, prototyping and debugging a custom linear circuit for converting a noisy low-level audio signal into a pure sine output, with the same amplitude. In other words a circuit that tracks both amplitude and frequency of a signal. The idea I have in mind is something like a phase-lock loop circuit. But I am receptive to an embedded/DSP solution, if it is low-cost. There is an existing prototype PCB, using low-pass filtering. But the noise band overlaps the signal band - like the hiss noise on a magnetic tape (cassette.) Freelancer must be proficient with Altium, or capable of translating Altium to Eagle.