A fully digital timing recovery scheme using two samples per symbol

In this paper, a new symbol timing recovery scheme is presented for digital receiver. The proposed algorithm belongs to the category of feedforward recovery and consists of two stages-phase estimation and interpolation. The phase estimation is to detect the clock phase of the sampled signal, which indicates the deviation of the reference sample from the point of maximum eye-opening. The interpolation which is implemented with an FIR filter is to reconstruct the transmitted symbols. Although many estimation algorithms have been developed in the literature, these methods usually need an input sampling rate of at least four samples per symbol. The proposed scheme requires only two samples/symbol, thus allowing the use of a very low sampling rate at the receiver. This feature is very important in the implementation of a digital receiver for high-rate transmission, since the hardware cost of the receiver depends heavily on the required processing speed