  Circular strings pulsating in $AdS_3 \times S^3 \times T^4$ with mixed R-R
and NS-NS three-form fluxes can be described by an integrable deformation of
the one-dimensional Neumann-Rosochatius mechanical model. In this article we
find a general class of pulsating solutions to this integrable system that can
be expressed in terms of elliptic functions. In the limit of strings moving in
$AdS_{3}$ with pure NS-NS three-form flux, where the action reduces to the
$SL(2,\mathbb{R})$ WZW model, we find agreement with the analysis of the
classical solutions of the system performed using spectral flow by Maldacena
and Ooguri. We use our elliptic solutions in $AdS_{3}$ to extend the dispersion
relation beyond the limit of pure NS-NS flux.
