[R] Cross Spectrum Analysis

2008-04-29 Thread Maura E Monville
I am reading some documentation about Cross Spectrum Analysis as a technique to compare spectra. My understanding is that it estimates the correlation strength between quasi-periodic structures embedded in two signals. I believe it may be useful for my signals analysis. I was referred to the R

Re: [R] Cross Spectrum Analysis

2008-04-30 Thread stephen sefick
$names [1] "freq" "spec" "coh" "phase" "kernel""df" [7] "bandwidth" "n.used""orig.n""series""snames""method" [13] "taper" "pad" "detrend" "demean" $freq and $spec are used to plot the power spectrum. freq is the x-axis and spec is the y-axis.

Re: [R] Cross Spectrum Analysis

2008-05-03 Thread Maura E Monville
In the case of muitivariate, from the documentation it looks like I can compare more than two signals at a time. Each column of the input matix seem to accommodate a signal. The problem is that my signals do NOT have the same number of samples (length). They were all collected at 30Hz so the sampli

Re: [R] Cross Spectrum Analysis

2008-05-04 Thread stephen sefick
is this a problem? are there error messages? if so could you provide them. Try as.matrix(yourdata). One thing you could do is create a moving average that reduces the signals to the lowest common denominator. Could you provide reproducable code with maybe a toy data set so anybody could have a

Re: [R] Cross Spectrum Analysis

2008-05-04 Thread Maura E Monville
R function "spectrum" expects a time series as input. I have attached a compressed archive with two detrended and denoised signals (txt format) whose spectra I would like to compare. I start out trying to generate a multivariate time series. Please, notice the different signals length. Moreover, R