Displaying 20 results from an estimated 2000 matches similar to: "spectral analysis"
2007 Jun 06
3
Spectral analysis
Hi all,
I am dealing with paleoceanographic data and I have a C14 time serie and one other variable. I would like to perform a spectral analysis (fft or wavelet) and plot it. Unfortunately I don't know the exact script to do this. Does anybody could send me an example to perform my spectral analysis ?
I Thank you
David
Changez de tĂȘte et de tenue tous les jours si vous le voulez !
2008 Dec 03
2
Spectral Analysis of Time Series in R
Dear R Community,
I am currently student at the Vienna University of Technology writing my
Diploma thesis on causality in time series and doing some analyses of
time series in R. I have the following questions:
(1) Is there a function in R to estimate the PARTIAL spectral coherence
of a multivariate time series? If yes, how does this work? Is there an
test in R if the partial spectral
2006 Jan 31
1
How do I "normalise" a power spectral density
I have done a fair bit of spectral analysis, and hadn't finished collecting my thoughts for a reply, so hadn't replied yet.
What exactly do you mean by normalize?
I have not used the functons periodogram or spectrum, however from the description for periodogram it appears that it returns the spectral density, which is already normalized by frequency, so you don't have to worry about
2002 Oct 22
3
Spectral phase information in residue vectors
I found this sentence in the Ogg format specs:
http://www.xiph.org/ogg/vorbis/doc/vorbis-spec-res.html
"A residue vector may represent spectral lines, spectral magnitude, spectral phase or hybrids as mixed by channel coupling."
But where does the spectral phase information come from ?
AFAIK MDCT doesn't provide any phase information.
And in OGG-encoding, MDCT is taking place a few
2007 Jan 08
2
Simple spectral analysis
Hello world,
I am actually trying to transfer a lecture from Statistica to
R and I ran into problems with spectral analysis, I think I
just don't get it 8-(
(The posting from "FFT, frequs, magnitudes, phases" from 2005
did not enlighten me)
As a starter for the students I have a 10year data set of air
temperature with daily values and I try to
get a periodogram where the annual
2011 Jul 11
1
Spectral Coherence
Greetings,
I would like to estimate a spectral coherence between
two timeseries. The stats : spectrum() returns a coh matrix
which estimates coherence (squared).
A basic test which from which i expect near-zero coherence:
x = rnorm(500)
y = rnorm(500)
xts = ts(x, frequency = 10)
yts = ts(y, frequency = 10)
gxy = spectrum( cbind( xts, yts ) )
plot( gxy $ freq, gxy $
2012 Oct 23
1
find similarity between two spectral profile
Hi,
I'm Pina and I'm a student in geology. I'm working with spectral profile of
sand and I have to find the similarity between one spectral profile selected
by hyperspectral image anche one that I created to mix different percentage
of 4 mineral component. I have to find the best mix of percentage of this 4
mineral in order to have the best likeness with the spectral profile chose
by
2006 Jan 27
2
How do I "normalise" a power spectral density analysis?
Hi everyone
Can anyone tell me how I normalise a power spectral density (PSD) plot of a
periodical time-series. At present I get the graphical output of spectrum VS
frequency.
What I want to acheive is period VS spectrum? Are these the same things but the
x-axis scale needs transformed ?
Any help would be greatly appreciated
Tom
2007 Jun 29
2
Spectral Decomposition
All of my resources for numerical analysis show that the spectral
decomposition is
A = CBC'
Where C are the eigenvectors and B is a diagonal matrix of eigen values.
Now, using the eigen function in R
# Original matrix
aa <- matrix(c(1,-1,-1,1), ncol=2)
ss <- eigen(aa)
# This results yields back the original matrix according to the formula
above
ss$vectors %*% diag(ss$values) %*%
2018 Apr 10
2
Spectral analisys for for R version 3.4.3
Dear all,
Is there any spectral analisys functionality available for R version 3.4.3?
Series() functionality doesn't work in this version.
Regards
Danniel
[[alternative HTML version deleted]]
2012 Jan 22
1
Problem with sapa package and spectral density function (SDF)
Hi everybody,
I'm a beginner R user and I'm trying to use the package "sapa" to
estimate the spectral density function of several time series using
the SDF function. For each time series, I want to calculate the
density function at two temporal resolutions (daily and monthly). The
monthly values calculated as a mean of the daily values. I first
create a ts object for both series
2003 Jul 03
2
SVD and spectral decompositions of a hermitian matrix
Hi:
I create a hermitian matrix and then perform its singular value
decomposition. But when I put it back, I don't get the original
hermitian matrix. I am having the same problem with spectral value
decomposition as well.
I am using R 1.7.0 on Windows. Here is my code:
X <- matrix(rnorm(16)+1i*rnorm(16),4)
X <- X + t(X)
X[upper.tri(X)] <- Conj(X[upper.tri(X)])
Y <-
2009 Mar 23
1
how to estimate multidimensional spectral measure of coherence
Please, does anyone know of an R packge to estimate multidimensional spectral measure of coherence within a moving time window ?
Some time ago I expeimented with a similar package that performs Cross Spectrum Analysis on the whole signal though.
Unluckily I deal with non-stationary signals whose properties change along with time. Therefore estimates can only be made over time periods
roughly
2002 May 17
1
Spectral Analysis
Dear R users
Is there a function in R to make a peridogram for
a spectral analysis of unevenlly sampled data??
something like spec.lomb() for S-Plus??
How to plot a vector with unequally spaced time series??
e.g
day/month/year V1
03/08/82 0.34
28/08/82 1.42
12/09/82 0.28
20/09/82 0.56
03/10/82 0.85
21/10/82 1.45
thanks
--
Marcelo Alexandre Bruno - Pos-graduacao Oceanografia Biologica
2008 Mar 27
6
help! - spectral analysis - spec.pgram
Can someone explain me this spec.pgram effect?
Code:
period.6<-c(0,0,0,0,0,10,0,0,0,0,0,10,0,0,0,0,0,10,0,0,0,0,0,10,0,0,0,0,0,10
,0,0,0,0,0,10,0,0,0,0,0,10,0,0,0,0,0,10,0,0,0,0,0,10,0,0,0,0,0,10)
period.5<-c(0,0,0,0,0,10,0,0,0,0,10,0,0,0,0,0,0,10,0,0,0,0,10,0,0,0,0,0,0,10
,0,0,0,0,10,0,0,0,0,0,0,10,0,0,0,0,10,0,0,0,0,0,0,10,0,0,0,0,10,0)
par(mfrow=c(2,1))
2005 Jun 03
0
noise poser spectral density
Dear Signal Processing Expert,
I would like to generate a random stationary signal of gaussian probability density function to simulate narrow band noise at the output of an IF amplifier. I know the receiver's system temperature (Ts) and IF bandwidth (B) therefore I assume that my narrow band noise mean power equals KTsB watts and therefore the power spectral density No=KTs per Hz.
Do you
2011 Feb 23
1
building zipped package with windows
Dear list,
i would like to build an own package using:
R CMD INSTALL --html --build --auto-zip -l folder spectral.methods
it seems to succeed as I get the following messages:
* installing *source* package 'spectral.methods' ...
** R
** data
Warning: empty 'data' directory
** preparing package for lazy loading
** help
*** installing help indices
converting help for package
2011 May 28
0
how to train ksvm with spectral kernel (kernlab) in caret?
Hello all,
I would like to use the train function from the caret package to
train a svm with a spectral kernel from the kernlab package. Sadly
a svm with spectral kernel is not among the many methods in caret...
using caret to train svmRadial:
------------------
library(caret)
library(kernlab)
data(iris)
TrainData<- iris[,1:4]
TrainClasses<- iris[,5]
set.seed(2)
2007 Jun 11
0
autoregressive spectral density estimate by andrews' plug-in method?
Hello!
I would like to ask if there is in R a function that estimates the spectral density function of a stochastic series at frequency zero by the "plug-in method", advocated by Andrews in his paper "Heteroscedasticity and Autocorrelation Consistent Covariance Matrix Estimation", Econometrica, 59,817-858. I saw R has functions that employ Andrews' plug-in method using an
2013 Feb 18
0
Computing Spectral Slope
Greetings,
I'm working on image classification and for that I want to use the spectral
slope as a feature for my classifier. For this I would prefer to calculate
this feature using R, so far I've read my image and converted it's RGB
representation into HSL. The spectral slope is computed over the Luminance
component, so at the moment what I have is a NxN matrix of Luminance values.