For Up Signal : Cross(Mov(CLOSE, 3, E),Mov(CLOSE, 15, E))
-- E Stands for Exponential Moving Average. If you want to use Simple Averages than replace E by S.
For Down Signal : Cross(Mov(CLOSE, 15, E),Mov(CLOSE, 3, E))
and In Filter Column Write : Cross(Mov(CLOSE, 3, E),Mov(CLOSE, 15, E)) OR Cross(Mov(CLOSE, 15, E),Mov(CLOSE, 3, E))