x <- rnorm(50)
y <- rnorm(50)
all.equal(convolve(x, y, conj = FALSE), rev(convolve(rev(y),x)))
n <- length(x <- -20:24)
y <- (x-10)^2/1000 + rnorm(x)/8
Han <- function(y) # Hanning
  convlv+        convolve(y, c(1,2,1)/4, type = "filter")