Symbol rate estimation of digital signals using wavelet transform without apriori knowledge

Automatic modulation identification of communication signals play an important role in electronic surveillance and electronic warfare systems. How to estimate symbol rate of digital signals without any apriori knowledge is a significant problem in the field of modulation identification. The wavelet transform (WT) can effectively extract the transient characteristics in a digital communication signal. In this paper, a method is discussed to estimate symbol rate of MPSK signals using wavelet transform without any apriori knowledge. If we choose a proper wavelet function, the WT magnitude of digital communication signals will peak at the time where phase changes occur. Consequently the separation of the peaks is an integral multiple of the symbol period. In addition, computer simulation results are given at last, which show good performance of the method even at low Carrier to Noise Ratio (CNR).