Decrease sample rate
Downsample a signal by an integer factor.
decimate(x, q, n = ifelse(ftype == "iir", 8, 30), ftype = "iir")
x |
input data, specified as a numeric vector or matrix. In case of a vector it represents a single signal; in case of a matrix each column is a signal. |
q |
decimation factor, specified as a positive integer. |
n |
Order of the filter used prior to the downsampling, specified as a
positive integer. Default: 8 if |
ftype |
filter type; either |
downsampled signal, returned as a vector or matrix.
Paul Kienzle, pkienzle@users.sf.net.
Conversion to R by Geert van Boxtel, G.J.M.vanBoxtel@gmail.com.
t <- seq(0, 2, 0.01) x <- chirp(t, 2, .5, 10, 'quadratic') + sin(2 * pi * t * 0.4) w <- 1:121 plot(t[w] * 1000, x[w], type = "h", col = "green") points(t[w] * 1000, x[w], col = "green") y = decimate(x, 4) lines(t[seq(1, 121, 4)] * 1000, y[1:31], type = "h", col = "red") points(t[seq(1, 121, 4)] * 1000, y[1:31], col = "red")
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