The calculated X-ray energy contents, spectra and pulse lengths for a range of simple target designs that include deuterium-tritium fuel surrounded by mercury are given. The calculations start with a compressed pellet core at the time of ignition and the evolution of the burning pellet is followed by using a plasma hydrodynamic-thermonuclear burn-radiative transfer computer code. It is shown that the pellet released radiation energy contents, spectra and pulse lengths depend upon pellet mass, density and material structure, and total yield.