Phase-Locked Loop using a comb filter with fractional delay

Abstract

A Phase Locked Loop is a feedback system combining a Voltage Controlled Oscillator and a Phase Comparator These are connected so that the oscillator maintains a constant phase angle relative to a reference signal. Phase locked loops can be used, for example to generate stable output frequency signals from a fixed frequency signal. A Comb Filter is a kind of Notch Filter (Non Recursive Filter) that is normally used to remove the harmonic terms from a particular signal. In this Design, a PLL is implemented using a Comb Filter because the main frequencies that are considered noise in the PLL loop are the harmonics of the fundamental frequency. There are 2 objectives of this project report, 1. Implementing Comb Filter Using Fractional Delay 2. Comparision of Frame Based and Typical Discrete Sample Based Implementation of a Comb Filter