  In this note we study the convergence of discrete to continuous non-linear
Fourier transforms. Relations between spectral problems and questions for
complex function theory provide a new approach for the study of scattering
problems and non-linear Fourier transform \cite{Scatter}. In particular,
non-linear Fourier transform can be viewed from the perspective of spectral
problems. Results in \cite{MP, PZ} can be viewed as results for non-linear
Fourier transform. These results are similar to some convergence problems for
discrete non-linear Fourier transform considered in \cite{T} and \cite{TT}.
