  We study the ionization of atomic hydrogen in the direction of polarization
due to a linearly polarized XUV pulse in the presence a strong field IR. We
describe the photoelectron spectra as an interference problem in the time
domain. Electron trajectories steming from different optical laser cycles give
rise to intercycle interference energy peaks known as sidebands. These
sidebands are modulated by a grosser structure coming from the intracycle
interference of the two electron trajectories born during the same optical
cycle. We make use of a simple semiclassical model which offers the possibility
to establish a connection between emission times and the photoelectron kinetic
energy. We compare the semiclassical predictions with the continuum-distorted
wave strong field approximation and the ab initio solution of the time
dependent Schr\"odinger equation. We analyze such interference pattern as a
function of the time delay between the IR and XUV pulse and also as a function
of the laser intensity.
