Formulas:
MiddleLine[i]=(MiddleLine[i-1]*(BandBars-1)+Close[i])/BandBars,
TopLine[i]=MiddleLine[i]+SmoothRange[i],
BottomLine[i]=MiddleLine[i]-SmoothRange[i], where
SmoothRange[i]=(SmoothRange[i-1]*(BandBars-1)+High[i]-Low[i])/BandBars.
MiddleLine[0]=Close[0],
SmoothRange[0]=High[0]-Low[0].
Download:
The indicator was revised and updated