The attempt to reconstruct high resolution spectrum using the interferogram of the Fabry-Perot interferometer has been achieved theoretically by solving an integral equation. But ordinarily, the solution of the equation is unstable. It is necessary to keep the antinoise ability at a level of 10-4 At present, it is very difficult to manufacture such a device, which attains this level. It is demonstrated by using computer simulation experiments that solving of the equation will become rather stable under certain conditions and the antinoise ability can be enhanced to 10-2. This result makes it possible to develop a satisfactory device.