Abstract – In this work we consider the problem of locating a known periodically embedded synchronization pattern in random data, which is subject to flat fading and additive white Gaussian noise. We derive the maximum likelihood rule and its high-SNR approximation for the case of noncoherent demodulation and show experimental results for the slow-fading Rayleigh channel. It is shown that the well-known correlation rule performs substantially worse than maximum-likelihood rule derived here.