Displaying 20 results from an estimated 1000 matches similar to: "Cross-Power Spectral Density and Welch's Method"
2006 Jan 24
0
Relating Spectral Density to Chi-Square distribution
Dear list,
I had some confusion regarding what function too use in order too relate
results from spec.pgram() too a chi-square distribution. The documentation
indicates that the PSD estimate can be approximated by a chi-square
distribution with 2 degrees of freedom, but I am having trouble figuring out
how to do it in R, and figuring out what specifically that statement in the
documentation
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
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
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
2006 Feb 02
0
How do I normalize a PSD?
Dear Tom,
Short answer, if your using spec.pgram(), use the smoothing kernel to get a
better estimate at the frequency centered in the bandwidth. If your
frequency bin of interest is wider than the bandwidth of the kernel, average
across frequencies (I think). The estimate appears to be normalized already.
If you are calculating your PSD independently, then oversample (e.g. 2,
perhaps 4 or more
2006 Jan 24
1
spec.pgram() normalized too what?
Dear list,
What on earth is spec.pgram() normalized too? If you would like to skip my
proof as to why it's not normed too the mean squared or sum squared
amplitude of the discrete function a[], feel free too skip the rest of the
message. If it is, but you know why it's not exact in spec.pgram() when it
should be, skip the rest of this message. The issue I refer herein refers
only too a
2024 Mar 04
0
Default t test in R is Welch's test, not Student's, and can be very problematic
Hi all.
I'm just writing to draw your attention to this paper, which is Open Access:
Curtis, D. Welch?s t test is more sensitive to real world violations of distributional assumptions than student?s t test but logistic regression is more robust than either. Stat Papers (2024). https://doi.org/10.1007/s00362-024-01531-7
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 Aug 05
1
trouble with looping for effect of sampling interval increase
I've looked everywhere and tinkered for three days now, so I figure asking
might be good.
So here's a general rundown of what I am trying to get my code to do I am
giving you the whole rundown because I need a solution that retain certain
ways of doing things because they give me the information i need.
I want to examine the effect of increasing my sampling interval on my data.
Example:
2016 Aug 26
2
Issue with acl_xattr:ignore system acls in 4.5rc2
On Fri, Aug 26, 2016 at 06:44:05PM +0200, Ralph Böhme wrote:
>
> Cheerio!
> -slow
Still reviewing this - but a few things that will need changing:
When adding the validate_nt_acl_blob() function in
[PATCH 06/12] vfs_acl_common: move the ACL blob validation to a helper function
this makes some of the existing function names in debug statements
incorrect.
Eg. validate_nt_acl_blob()
2016 Aug 29
1
Issue with acl_xattr:ignore system acls in 4.5rc2
On Sat, Aug 27, 2016 at 12:46:12PM +0200, Ralph Böhme via samba wrote:
>
> ...and this one even has bug urls in all commit messages. Sorry for
> forgetting this in the previous version.
Juuuusttt *one* leetle change, sorry :-).
I was following the changes to the talloc heirarchy in the
code and realized that adding the following change made it
much clearer (at least to me).
diff --git
2012 Jul 24
0
setar function error message (SOLVED)
Hi,
I know the problem now. Previously i use as.timeSeries function, but the
error message of setar function still came out. Anyway, many thanks to
Pascal for the solution.
Best Regards,
Ario
On Mon, Jul 23, 2012 at 4:28 PM, Pascal Oettli <kridox@ymail.com> wrote:
> Hello,
>
> It works for me (with a warning message), by adding this line before the
> setar procedure:
>
>
2013 Jun 02
2
HELP: Ayuda URGENTE CON MODELO ARMA EN R y Autocorrelación.
> Cordial saludos a tod en s.
>
> Estoy leyendo un tema y tengo la siguiente necesidad.
>
> Los contacto para pedirles MUY ENCARECIDAMENTE ME AYUDEN con la
> explicación DE CÓMO HACER EL MODELO ARMA en R DE UNA SEÑAL CUALQUIERA para
> obtener de ella el modelo matemático fraccional aproximado, esto para
> obtener el PSD de la señal (Power Density Spectrum).
>
> La
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
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
2008 Dec 22
3
Summary information by groups programming assitance
All -
I have data that looks like
psd Species Lake Length Weight St.weight Wr
Wr.1 vol
432 substock SMB Clear 150 41.00 0.01 95.12438
95.10118 0.0105
433 substock SMB Clear 152 39.00 0.01 86.72916
86.70692 0.0105
434 substock SMB Clear 152 40.00 3.11 88.95298
82.03689 3.2655
435 substock SMB Clear
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 tête 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
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)
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
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