Electrocardiogram data
These data were measured during the normal sinus rhythm of a patient who occasionally experiences arrhythmia. There are 2048 observations measured in units of millivolts and collected at a rate of 180 samples per second. This time series is a good candidate for a multiresolution analysis because its components are on different scales. For example, the large scale (low frequency) fluctuations, known as baseline drift, are due to the patient respiration, while the prominent short scale (high frequency) intermittent fluctuations between 3 and 4 seconds are evidently due to patient movement. Heart rhythm determines most of the remaining features in the series. The large spikes occurring about 0.7 seconds apart the R waves of normal heart rhythm; the smaller, but sharp peak coming just prior to an R wave is known as a P wave; and the broader peak that comes after a R wave is a T wave.
data(ecg)
A vector of class ts containing 2048 observations.
Gust Bardy and Per Reinhall, University of Washington
Percival, D. B., and Walden, A.T. (2000) Wavelet Methods for Time Series Analysis, Cambridge University Press.
## Not run:
# figure 130 in Percival and Walden (2000)
if (requireNamespace("waveslim") == TRUE) {
data(ecg)
ecg.level <- haar2level(ecg)
ecg.haar <- orthobasis.haar(length(ecg))
ecg.mld <- mld(ecg, ecg.haar, ecg.level, plot = FALSE)
res <- cbind.data.frame(apply(ecg.mld[,1:5],1,sum), ecg.mld[,6:11])
par(mfrow = c(8,1))
par(mar = c(2, 5, 1.5, 0.6))
plot(as.ts(ecg), ylab = "ECG")
apply(res, 2, function(x) plot(as.ts(x), ylim = range(res),
ylab = ""))
par(mfrow = c(1,1))
}
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