  This study investigates the phase retrieval problem for wide-band signals. We
solve the following problem: given f $\in$ L 2 (R) with Fourier transform in L
2 (R, e^{2c|x|} dx), we find all functions g $\in$ L 2 (R) with Fourier
transform in L 2 (R, e^{2c|x| dx}), such that |f (x)| = |g(x)| for all x $\in$
R. To do so, we first translate the problem to functions in the Hardy spaces on
the disc via a conformal bijection, and take advantage of the inner-outer
factorization. We also consider the same problem with additional constraints
involving some transforms of f and g, and determine if these constraints force
uniqueness of the solution.
