FXM

From Synthesizer Wiki

Roland has a special little "dirtmaker" thing introduced with the early JV Series like the JD990 and the JV1080 series and still in the Fantom Series, the FXM, it is in fact a limited Crossmodulation and the official name (the acronym) is for Frequency Cross Modulation. Hat has 2 Parameters. Colour and Depth. Not really Hi-Resolution, but allows some typical "metallic" artefacts, but not as fine as one previous (seamless) Xmod variants. Btw. the Xmod is modulated by a square wave Osc. and can not be changed much exept the rough settings colour & depth.