tukeywin {gsignal}

Tukey (tapered cosine) window

Description

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

Usage

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.

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.

Value

Tukey window, returned as a vector.

Author(s)

Laurent Mazet, [e-mail].
Conversion to R by Geert van Boxtel, [e-mail].

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)