The Noise Canceler (ノイズキャンセラー Noizu Kyanserā) is an upgrade for the Idea Engine made by Kokonoe Mercury that is installed on Ragna the Bloodedge. It cancels out the effect of Celica A. Mercury's ability to negate the Magic Element whenever she is around Ragna.
In BlazBlue: Chronophantasma, Kokonoe installed a machine upon Ragna to gather data surrounding him and Celica, however, the machine would seemingly only work if the duo were in close proximity. As a measure to ensure the two would stay close, Kokonoe tricked the two by claiming that the machine was in fact a Multi-Dimension Bomb that would detonate should they become separated; this ruse hindered the duo for the majority of BlazBlue: Chronophantasma.
Eventually, when enough data was gathered and analyzed, Kokonoe created the Noise Canceler so Ragna's Blue Grimoire and right eye would work while in the presence of Celica, meaning he can better fend himself when the two are close.