Synthetic aperture radar (SAR) applications related to phase estimation, just as studies on subsidence, generation of digital elevation models or time series analyses of Earth surface changes, require an adequate phase unwrapping (PU) process. This process should imply at least a qualitative fringe analysis of certain small regions of the complete interferogram. Although, this qualitative analysis is usually omitted or cannot be followed due to its complexity, sometimes the form of the observed fringes allows it. In general, the form of the estimated phase depends on the properties or capabilities of the PU algorithm used, as well as its input parameters, and these points may be unknown for the user. For instance, in applications with Sentinel-1 images, we have an algorithm called SNAPHU, which is quite robust and effective. Nevertheless, sometimes, it produces inconsistent results according to the theoretical form of the fringes and the expected form of the phase. Consequently, the proposal to solve these failed results could involve implementing different PU routines, that can be more familiar or relatively easy-to-program, as the fast Fourier transform (FFT) based method. In this manuscript, we describe a simple way to do this analysis, considering a small subset of a SAR deformation interferogram, and three particular PU algorithms; SNAPHU, the FFT based method, and a proposal or extension of this last one, but based on the use of continuous Fourier transforms.