As the most simple examples of wavelets and scaling functions which are expressed in terms of their Fourier transforms, we construct and study the generalized Shannon wavelets (G-Shannon wavelets) and the generalized Shannon scaling functions (G-Shannon scaling functions) whose Fourier transforms are given by characteristic functions. One of the features of the G-Shannon wavelets is that they may or may not be associated with MRA. We characterize those G-Shannon wavelets which can be associated with MRA and give a criterion to determine whether a wavelet from a class of G-Shannon wavelets of Ha et al. can be associated with MRA or not. Another feature of the G-Shannon wavelets is the convergence of a G-Shannon wavelet expansion influenced by the slow decay of the G-Shannon wavelets. We study the pointwise convergence and the Gibbs phenomenon on the G-Shannon wavelet expansions. In contrast to the regular wavelet expansion, there is a continuous function whose G-Shannon wavelet expansion diverges. We also see that the G-Shannon wavelet is a sampling function and has the corresponding sampling theorem. By the smoothing procedure of Meyer, the generalized Meyer wavelet is constructed from the G-Shannon wavelet which has a fast decay and satisfies an oversampling theorem.