where did the doctor get his mobile emitter
The Doctor (Star Trek: Voyager) The Doctor later acquired a mobile holographic emitter from the 29th century.[4] Although he had previously been confined to Sickbay or the Holodeck, the mobile emitter allowed The Doctor to move about freely, making him ideal for missions where the environment would be harmful or otherwise fatal to the crew. In one notable incident, when an away team was trapped on a radioactive planet, The Doctor was able to infiltrate the people and almost single-handedly rescue the team because, as he pointed out, being a hologram renders him immune to the radiation, stating that "being a hologram does have its advantages."