Provided are an endoscopic system, a processor device, a light source device, and an operation method that reduce oxygen saturation artifacts that appear during magnified observation. The light source device (14) of the endoscopic system (10) is capable of emitting signal light in a light emission pattern A, which irradiates a signal light (LA1) with a center wavelength of λA1 and a signal light (LA2) with a center wavelength of λA2 respectively on the test object, and a light emission pattern (B), which irradiates a signal light (LB1) with a center wavelength of λB1 and a signal light (LB2) with a center wavelength of λB2 respectively on the test object. The respective center wavelengths λA1, λA2, λB1, and λB2 satisfy λA1 - λA2 > λB1 - λB2. An oxygen saturation-calculating part (83) is contained in an oxygen saturation image-generating section (76) and calculates the oxygen saturation for each pixel, which receives reflected light from the signal light (LA1) and reflected light from the signal light (LA2) when light emission pattern A is used and receives reflected light from the signal light (LB1) and reflected light from the signal light (LB2) when light emission pattern B is used, on the basis of the ratio of the respective image signals output from the same pixel. A control unit (67) switches the light emission pattern of the light source device (14) between light emission pattern A and light emission pattern B.La présente invention concerne un système endoscopique, un dispositif processeur, un dispositif source lumineuse et un procédé de fonctionnement qui réduisent des artéfacts de saturation en oxygène qui apparaissent pendant une observation agrandie. Le dispositif (14) source lumineuse du système (10) endoscopique est apte à émettre une lumière de signalisation dans un profil A démission de lumière, qui expose respectivement un objet testé à une lumière de signalisation (LA1) avec une longueur donde centrale de λA1 et à une lumière de signalisation (LA2) a
