Time delay estimation (TDE) techniques have many diverse signal processing applications: for instance, in such fields as radar, sonar, seismology, geophysics, and ultrasonics for identifying and localizing radiating sources. In this case study, we evaluate the performance of two algorithms developed by Markus Nentwig to find delay and scaling factor between two cyclic signals. The first algorithm uses linear least-squares fitting to estimate the delay. The second algorthm is iterative and relies on FFT-based cross-correlation. A MATLAB® implementation of both approaches can be found in Algorithm 1 and Algorithm 2, respectively. As the author pointed out, the algorithms are not suited for real-time applications since the whole signal needs to be known in advance. However, they can be very useful …