No vol data vwap like bands

study(title = "POC Dots", shorttitle="POC Dots", overlay=true)
resCustom = input(title="Timeframe", type=resolution, defval="15")
Length = input(4, minval=1)
xPrice = security(tickerid, resCustom, hlc3)
xvnoise = abs(xPrice - xPrice[1])
nfastend = 0.666
nslowend = 0.0645
nsignal = abs(xPrice - xPrice[Length])
nnoise = sum(xvnoise, Length)
nefratio = iff(nnoise != 0, nsignal / nnoise, 0)
nsmooth = pow(nefratio * (nfastend - nslowend) + nslowend, 2) 
nAMA = nz(nAMA[1]) + nsmooth * (xPrice - nz(nAMA[1]))
basis = nAMA

BB_length = input(24, minval=1,maxval=100)
BB_stdDev = input(2, minval=1, maxval=3)

dev = BB_stdDev * stdev(nAMA, BB_length)
upper = basis + dev
lower = basis - dev
plot(basis, color=red)
p1 = plot(upper, color=blue)
p2 = plot(lower, color=blue)
fill(p1,p2, blue)