The Heisenberg compensator is a component of the transporter system.
It works around the problems caused by the Heisenberg uncertainty principle (hence the name), allowing the transporter sensors to compensate for the inability to determine the position and momentum of the target particles to the same degree of accuracy. This ensures the matter stream remains coherent during transport, and no data is lost. (TNG: "Realm of Fear")
While trying to devise a way to transport holographic matter off the holodeck without it disintegrating instantly, the idea was put forth that decoupling the Heisenberg compensators might let the matter reform normally, although the suggestion was used as a stalling tactic against Professor James Moriarty, and the idea had never actually been tried before.
- When asked by Time Magazine in 1994, "How do the Heisenberg compensators work?" Mike Okuda replied, "They work just fine, thank you." [Benjamin Chee]