tukeywin function

Tukey (tapered cosine) window

Return the filter coefficients of a Tukey window (also known as the cosine-tapered window) of length n.

tukeywin(n, r = 1/2)

Arguments

• n: Window length, specified as a positive integer.

• r: Cosine fraction, specified as a real scalar. The Tukey window is a rectangular window with the first and last r / 2 percent of the samples equal to parts of a cosine. For example, setting r = 0.5

  (default) produces a Tukey window where 1/2 of the entire window length consists of segments of a phase-shifted cosine with period 2r = 1. If you specify r <= 0, an n-point rectangular window is returned. If you specify r >= 1, an n-point von Hann window is returned.

Returns

Tukey window, returned as a vector.

Details

The Tukey window, also known as the tapered cosine window, can be regarded as a cosine lobe that is convolved with a rectangular window. r defines the ratio between the constant section and and the cosine section. It has to be between 0 and 1. The function returns a Hann window for r equal to 1 and a rectangular window for r equal to 0.

Examples

n <- 128
t0 <- tukeywin(n, 0)        # Equivalent to a rectangular window
t25 <- tukeywin(n, 0.25)
t5 <- tukeywin(n)           # default r = 0.5
t75 <- tukeywin(n, 0.75)
t1 <- tukeywin(n, 1)         # Equivalent to a Hann window
plot(t0, type = "l", xlab = "Samples", ylab =" Amplitude", ylim=c(0,1.2))
lines(t25, col = 2)
lines(t5, col = 3)
lines(t75, col = 4)
lines(t1, col = 5)

Author(s)

Laurent Mazet, mazet@crm.mot.com .

Conversion to R by Geert van Boxtel, G.J.M.vanBoxtel@gmail.com .