How to figure out rms spectral averaging?

I have a lot of signals and I would like to figure out the averaged spectrum. How can I perform the rms spectral averaging in matlab? I want to perform the averaging explained at page 5 on this pdf http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.w thanks Pietro

"pietro " <bracardi82@email.it> wrote in message <ibsgpo$9cd$1@fred.mathworks.com>... > I have a lot of signals and I would like to figure out the averaged spectrum. How can I perform the rms spectral averaging in matlab? I want to perform the averaging explained at page 5 on this pdf http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.w > > thanks > Pietro This is the properly link, in which it is explained the rms speactra averaging http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.pdf

"pietro " <bracardi82@email.it> wrote in message <ibtf8n$g7f$1@fred.mathworks.com>... > "pietro " <bracardi82@email.it> wrote in message <ibsgpo$9cd$1@fred.mathworks.com>... > > I have a lot of signals and I would like to figure out the averaged spectrum. How can I perform the rms spectral averaging in matlab? I want to perform the averaging explained at page 5 on this pdf http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.w > > > > thanks > > Pietro > > This is the properly link, in which it is explained the rms speactra averaging > > http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.pdf Hi Pietro, This is what they call their "linear weighting" t = linspace(0,1,1000); x = cos(2*pi*250*t)'; for k = 1:10 y = x+randn(size(x)); ydft(:,k) = abs(fft(y)); end xdftavg = mean(ydft,2); I've used a two-sided spectral estimate here. If you only want one-sided, you just need to make the necessary adjustment. You can also do this with spectral objects if you have the Signal Processing Toolbox as follows: hper = spectrum.periodogram; for k = 1:10 y = x+randn(size(x)); psdest = psd(hper,y,'NFFT',length(y),'Fs',1000); yper(:,k) = psdest.Data; end xdftavg = mean(yper,2); plot(psdest.Frequencies,10*log10(xdftavg)); Note this results in a one-sided estimate by default. Hope that helps, Wayne

"Wayne King" <wmkingty@gmail.com> wrote in message <ibtqb3$8fp$1@fred.mathworks.com>... > "pietro " <bracardi82@email.it> wrote in message <ibtf8n$g7f$1@fred.mathworks.com>... > > "pietro " <bracardi82@email.it> wrote in message <ibsgpo$9cd$1@fred.mathworks.com>... > > > I have a lot of signals and I would like to figure out the averaged spectrum. How can I perform the rms spectral averaging in matlab? I want to perform the averaging explained at page 5 on this pdf http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.w > > > > > > thanks > > > Pietro > > > > This is the properly link, in which it is explained the rms speactra averaging > > > > http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.pdf > > Hi Pietro, This is what they call their "linear weighting" > > t = linspace(0,1,1000); > x = cos(2*pi*250*t)'; > for k = 1:10 > y = x+randn(size(x)); > ydft(:,k) = abs(fft(y)); > end > > xdftavg = mean(ydft,2); > > I've used a two-sided spectral estimate here. If you only want one-sided, you just need to make the necessary adjustment. You can also do this with spectral objects if you have the Signal Processing Toolbox as follows: > > hper = spectrum.periodogram; > for k = 1:10 > y = x+randn(size(x)); > psdest = psd(hper,y,'NFFT',length(y),'Fs',1000); > yper(:,k) = psdest.Data; > end > xdftavg = mean(yper,2); > plot(psdest.Frequencies,10*log10(xdftavg)); > > Note this results in a one-sided estimate by default. > > Hope that helps, > Wayne thanks a lot, maybe I haven't understood the code, but it doesn't figure out the rms averaging, doesn't it? Try to take a look at this link: http://zone.ni.com/reference/en-XX/help/371361E-01/lvanlsconcepts/average_improve_measure_freq/

"pietro " <bracardi82@email.it> wrote in message <ibu5h7$5mb$1@fred.mathworks.com>... > "Wayne King" <wmkingty@gmail.com> wrote in message <ibtqb3$8fp$1@fred.mathworks.com>... > > "pietro " <bracardi82@email.it> wrote in message <ibtf8n$g7f$1@fred.mathworks.com>... > > > "pietro " <bracardi82@email.it> wrote in message <ibsgpo$9cd$1@fred.mathworks.com>... > > > > I have a lot of signals and I would like to figure out the averaged spectrum. How can I perform the rms spectral averaging in matlab? I want to perform the averaging explained at page 5 on this pdf http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.w > > > > > > > > thanks > > > > Pietro > > > > > > This is the properly link, in which it is explained the rms speactra averaging > > > > > > http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.pdf > > > > Hi Pietro, This is what they call their "linear weighting" > > > > t = linspace(0,1,1000); > > x = cos(2*pi*250*t)'; > > for k = 1:10 > > y = x+randn(size(x)); > > ydft(:,k) = abs(fft(y)); > > end > > > > xdftavg = mean(ydft,2); > > > > I've used a two-sided spectral estimate here. If you only want one-sided, you just need to make the necessary adjustment. You can also do this with spectral objects if you have the Signal Processing Toolbox as follows: > > > > hper = spectrum.periodogram; > > for k = 1:10 > > y = x+randn(size(x)); > > psdest = psd(hper,y,'NFFT',length(y),'Fs',1000); > > yper(:,k) = psdest.Data; > > end > > xdftavg = mean(yper,2); > > plot(psdest.Frequencies,10*log10(xdftavg)); > > > > Note this results in a one-sided estimate by default. > > > > Hope that helps, > > Wayne > > thanks a lot, maybe I haven't understood the code, but it doesn't figure out the rms averaging, doesn't it? > Try to take a look at this link: > http://zone.ni.com/reference/en-XX/help/371361E-01/lvanlsconcepts/average_improve_measure_freq/ Hi, the previous link you included described the lnear RMS average as the mean of the spectral magnitudes. It looks just like what is described in your latest link. What they are calling "vector averaging" averages the complex-valued DFT coefficients. Wayne

"Wayne King" <wmkingty@gmail.com> wrote in message <ibu6qf$csv$1@fred.mathworks.com>... > "pietro " <bracardi82@email.it> wrote in message <ibu5h7$5mb$1@fred.mathworks.com>... > > "Wayne King" <wmkingty@gmail.com> wrote in message <ibtqb3$8fp$1@fred.mathworks.com>... > > > "pietro " <bracardi82@email.it> wrote in message <ibtf8n$g7f$1@fred.mathworks.com>... > > > > "pietro " <bracardi82@email.it> wrote in message <ibsgpo$9cd$1@fred.mathworks.com>... > > > > > I have a lot of signals and I would like to figure out the averaged spectrum. How can I perform the rms spectral averaging in matlab? I want to perform the averaging explained at page 5 on this pdf http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.w > > > > > > > > > > thanks > > > > > Pietro > > > > > > > > This is the properly link, in which it is explained the rms speactra averaging > > > > > > > > http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.pdf > > > > > > Hi Pietro, This is what they call their "linear weighting" > > > > > > t = linspace(0,1,1000); > > > x = cos(2*pi*250*t)'; > > > for k = 1:10 > > > y = x+randn(size(x)); > > > ydft(:,k) = abs(fft(y)); > > > end > > > > > > xdftavg = mean(ydft,2); > > > > > > I've used a two-sided spectral estimate here. If you only want one-sided, you just need to make the necessary adjustment. You can also do this with spectral objects if you have the Signal Processing Toolbox as follows: > > > > > > hper = spectrum.periodogram; > > > for k = 1:10 > > > y = x+randn(size(x)); > > > psdest = psd(hper,y,'NFFT',length(y),'Fs',1000); > > > yper(:,k) = psdest.Data; > > > end > > > xdftavg = mean(yper,2); > > > plot(psdest.Frequencies,10*log10(xdftavg)); > > > > > > Note this results in a one-sided estimate by default. > > > > > > Hope that helps, > > > Wayne > > > > thanks a lot, maybe I haven't understood the code, but it doesn't figure out the rms averaging, doesn't it? > > Try to take a look at this link: > > http://zone.ni.com/reference/en-XX/help/371361E-01/lvanlsconcepts/average_improve_measure_freq/ > > Hi, the previous link you included described the lnear RMS average as the mean of the spectral magnitudes. It looks just like what is described in your latest link. What they are calling "vector averaging" averages the complex-valued DFT coefficients. > > Wayne thanks a lot Wayne, How can I perform vector averaging with matlab?

"pietro " <bracardi82@email.it> wrote in message <ic3doc$mqp$1@fred.mathworks.com>... > "Wayne King" <wmkingty@gmail.com> wrote in message <ibu6qf$csv$1@fred.mathworks.com>... > > "pietro " <bracardi82@email.it> wrote in message <ibu5h7$5mb$1@fred.mathworks.com>... > > > "Wayne King" <wmkingty@gmail.com> wrote in message <ibtqb3$8fp$1@fred.mathworks.com>... > > > > "pietro " <bracardi82@email.it> wrote in message <ibtf8n$g7f$1@fred.mathworks.com>... > > > > > "pietro " <bracardi82@email.it> wrote in message <ibsgpo$9cd$1@fred.mathworks.com>... > > > > > > I have a lot of signals and I would like to figure out the averaged spectrum. How can I perform the rms spectral averaging in matlab? I want to perform the averaging explained at page 5 on this pdf http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.w > > > > > > > > > > > > thanks > > > > > > Pietro > > > > > > > > > > This is the properly link, in which it is explained the rms speactra averaging > > > > > > > > > > http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.pdf > > > > > > > > Hi Pietro, This is what they call their "linear weighting" > > > > > > > > t = linspace(0,1,1000); > > > > x = cos(2*pi*250*t)'; > > > > for k = 1:10 > > > > y = x+randn(size(x)); > > > > ydft(:,k) = abs(fft(y)); > > > > end > > > > > > > > xdftavg = mean(ydft,2); > > > > > > > > I've used a two-sided spectral estimate here. If you only want one-sided, you just need to make the necessary adjustment. You can also do this with spectral objects if you have the Signal Processing Toolbox as follows: > > > > > > > > hper = spectrum.periodogram; > > > > for k = 1:10 > > > > y = x+randn(size(x)); > > > > psdest = psd(hper,y,'NFFT',length(y),'Fs',1000); > > > > yper(:,k) = psdest.Data; > > > > end > > > > xdftavg = mean(yper,2); > > > > plot(psdest.Frequencies,10*log10(xdftavg)); > > > > > > > > Note this results in a one-sided estimate by default. > > > > > > > > Hope that helps, > > > > Wayne > > > > > > thanks a lot, maybe I haven't understood the code, but it doesn't figure out the rms averaging, doesn't it? > > > Try to take a look at this link: > > > http://zone.ni.com/reference/en-XX/help/371361E-01/lvanlsconcepts/average_improve_measure_freq/ > > > > Hi, the previous link you included described the lnear RMS average as the mean of the spectral magnitudes. It looks just like what is described in your latest link. What they are calling "vector averaging" averages the complex-valued DFT coefficients. > > > > Wayne > > thanks a lot Wayne, > > How can I perform vector averaging with matlab? Hi Pietro, What they are calling "vector averaging" is just averaging the complex-valued DFT coefficients instead of their magnitudes. So just substitute: ydft(:,k) = fft(y); for ydft(:,k) = abs(fft(y)); in the example code I gave you. Wayne

"Wayne King" <wmkingty@gmail.com> wrote in message <ic3jnn$5hg$1@fred.mathworks.com>... > "pietro " <bracardi82@email.it> wrote in message <ic3doc$mqp$1@fred.mathworks.com>... > > "Wayne King" <wmkingty@gmail.com> wrote in message <ibu6qf$csv$1@fred.mathworks.com>... > > > "pietro " <bracardi82@email.it> wrote in message <ibu5h7$5mb$1@fred.mathworks.com>... > > > > "Wayne King" <wmkingty@gmail.com> wrote in message <ibtqb3$8fp$1@fred.mathworks.com>... > > > > > "pietro " <bracardi82@email.it> wrote in message <ibtf8n$g7f$1@fred.mathworks.com>... > > > > > > "pietro " <bracardi82@email.it> wrote in message <ibsgpo$9cd$1@fred.mathworks.com>... > > > > > > > I have a lot of signals and I would like to figure out the averaged spectrum. How can I perform the rms spectral averaging in matlab? I want to perform the averaging explained at page 5 on this pdf http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.w > > > > > > > > > > > > > > thanks > > > > > > > Pietro > > > > > > > > > > > > This is the properly link, in which it is explained the rms speactra averaging > > > > > > > > > > > > http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutFFTs.pdf > > > > > > > > > > Hi Pietro, This is what they call their "linear weighting" > > > > > > > > > > t = linspace(0,1,1000); > > > > > x = cos(2*pi*250*t)'; > > > > > for k = 1:10 > > > > > y = x+randn(size(x)); > > > > > ydft(:,k) = abs(fft(y)); > > > > > end > > > > > > > > > > xdftavg = mean(ydft,2); > > > > > > > > > > I've used a two-sided spectral estimate here. If you only want one-sided, you just need to make the necessary adjustment. You can also do this with spectral objects if you have the Signal Processing Toolbox as follows: > > > > > > > > > > hper = spectrum.periodogram; > > > > > for k = 1:10 > > > > > y = x+randn(size(x)); > > > > > psdest = psd(hper,y,'NFFT',length(y),'Fs',1000); > > > > > yper(:,k) = psdest.Data; > > > > > end > > > > > xdftavg = mean(yper,2); > > > > > plot(psdest.Frequencies,10*log10(xdftavg)); > > > > > > > > > > Note this results in a one-sided estimate by default. > > > > > > > > > > Hope that helps, > > > > > Wayne > > > > > > > > thanks a lot, maybe I haven't understood the code, but it doesn't figure out the rms averaging, doesn't it? > > > > Try to take a look at this link: > > > > http://zone.ni.com/reference/en-XX/help/371361E-01/lvanlsconcepts/average_improve_measure_freq/ > > > > > > Hi, the previous link you included described the lnear RMS average as the mean of the spectral magnitudes. It looks just like what is described in your latest link. What they are calling "vector averaging" averages the complex-valued DFT coefficients. > > > > > > Wayne > > > > thanks a lot Wayne, > > > > How can I perform vector averaging with matlab? > > Hi Pietro, What they are calling "vector averaging" is just averaging the complex-valued DFT coefficients instead of their magnitudes. So just substitute: > > ydft(:,k) = fft(y); > > for > ydft(:,k) = abs(fft(y)); > > in the example code I gave you. > > Wayne Thank Wayne I will test it. Bye Pietro

Similiar Articles:

Cadence Calculator to get average power - comp.cad.cadence ...
How to figure out rms spectral averaging? - comp.soft-sys.matlab ... How to figure out rms spectral averaging? - comp.soft-sys.matlab ... PSD of clipped OFDM signal - comp ...

Calculating mean value - comp.soft-sys.matlab
How to figure out rms spectral averaging? - comp.soft-sys.matlab ..... to calculate mean values ... is just the average of ... voltage of a common AC wave form... with a ...

how can i rasterize a vector pdf? - comp.text.pdf
How to figure out rms spectral averaging? - comp.soft-sys.matlab ... how can i rasterize a vector pdf? - comp.text.pdf How to figure out rms spectral averaging? - comp ...

Signal-to-noise ratio for a sine signal?? - comp.soft-sys.matlab ...
Take RMS of the normalized input signal over a ... negative SNR mostly because the energy spreads out ... because according to Parseval's theorem, the average spectral ...

How to calculate Eb/No? - comp.dsp
The desired bit energy to noise power spectral density ratio can be written ... How to calculate Eb/No? - comp.dsp How to calculate effective/average paged memory access time ...

how to calculate the noise variance for AWGN - comp.soft-sys ...
can some one help to find out the mistake i made? ... calculate noise variance from noise power spectral density ... calculate ... phase error variance to rms phase error - comp ...

SNR calculation using FFT - comp.dsp
Hi all, Currently, I use FFT to calculate the ... the bins as a histogram would come out ... Calculate FFT in blocks and then average it. - comp.dsp SNR calculation using ...

How to get the average energy of QAM - comp.dsp
... of math tables someplace) -- then you can work it all out ... No? - comp.dsp The desired bit energy to noise power spectral density ... How to calculate effective/average ...

Calculate FFT in blocks and then average it. - comp.dsp
He had evidently pointed me out to her ... Calculate FFT in blocks and then average it. - comp.dsp... need to calculate the RMS ... Hi DSP experts, I want to do spectral ...

Reducing noise impact in FFT: averaged segment method - comp.dsp ...
As far as I know, averaging spectral magnitudes or averaging spectral powers ... is a paper you can > >Wow Dale, > >For the life of me I can't figure out why ...

How to figure out rms spectral averaging? - Newsreader - MATLAB ...
I have a lot of signals and I would like to figure out the averaged spectrum. How can I perform the rms spectral averaging in matlab? I want to perform the averaging ...

How to Calculate an RMS | eHow.com
The Root Mean Square, or quadratic mean, is a ... and is a formula that is used to calculate an approximate average... ... Check It Out

7/22/2012 2:57:43 AM