I didn't say infinite power, but infinite power density at the sine wave
frequemcy.
Being per Hz doesn't mean that one computes the PSD using a 1 Hz band! It
means that one divides the power in the band by the width of the band,
which can be anything one chooses.
The formula for S(f) of a si
spectral density is by convention a 1Hz
binwidth, not an arbitrary one, units of A^2/Hz.
perhaps if you manually compute the spectral density of a sine wave,
you will easily see
that they don't have infinite power, R is the autocorrelation of the
Asin(wt):
Back to the original question:
Is
There is certainly differences (usually of a factor of PI) in the various
definitions used for PSDs, but a simple sign wave has an infinite power
density at the sine wave frequency. Are we agreed on that?
Use of windowing will modify this comment somewhat (so it probably won't
really go to inf
is the suggestion that the matplotlib
algorithm is correct in computing PSD amplitudes?
btw, increasing nFFT increases the number of points used in the FFT,
which
increases the spectral frequency resolution (smaller binwidth)
but for a limited data set
of N points, as is the case in the examp
If you lower the resolution (ie increase nFFT) in your program you will
see that the PSD does indeed increase. I think it may be on the way to
infinity.
Joseph Park <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
26/10/2007 10:05 AM
To
matplotlib-users@lists.sourceforge.net
cc
Subject
Re:
Shouldn't the PSD for a simple sine
wave tend to infinity
the spectral resolution
will impact the amplitude, if you
are not dealing with a density. by definition a spectral density
has applied the bandwidth resolution correction. the PSD amplitude
should correspond to the RMS amplitude of the
Are you sure that the answer should be zero? Shouldn't the PSD for a
simple sine wave tend to infinity (depending on the resolution)?
Joseph Park <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
26/10/2007 06:50 AM
To
matplotlib-users@lists.sourceforge.net
cc
Subject
[Matplotlib-users] PSD
Please try the attached script.
The answer should be ~0 dB for each of the frequencies.
Most likely a simple scaling issue/parameter of which i'm ignorant.
--
##
## Name: psd_scale.py
##
## Purpose
Yep that can be a good idea. I don't know anything on how mathtext is working
but I'm not completely sure that the problem is with freetype because
sometime that can work. In reality every character I tested worked but you
have to put in a certain order. To understand a little bit more what I tr
Darren Dale wrote:
> Hi Mike,
>
> On Tuesday 23 October 2007 09:05:56 am Michael Droettboom wrote:
>> Unfortunately, I can't reproduce this on my machine even with the latest
>> stable version of freetype-2.5.3 (which is the same version in Ubuntu
>> Gutsy).
>
> I think you mean freetype-2.3.5. I
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Hello folks,
I have a Gaussian peak centered on zero. When the plot is drawn on
screen with the GTKAgg backend, the peak is shown in the correct place.
When I either click on the disk icon and save the plot as eps or use
savefig, the peak is shifted
A simple solution would be:
numbers, text = yticks()
mytext = ['%.2f' % n for n in numbers]
yticks(numbers, mytext)
If you need fancier formatting look at Ticker and Formatter API
http://matplotlib.sourceforge.net/matplotlib.ticker.html
For sure there's something about this in the examples as wel
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