# What is power spectral density?

I want to know the exact meaning of power spectral density, by a suitable real life example. There are a lot of definition but how can I correlate it with real experiences?

I want to know the exact meaning of power spectral density, by a suitable real life example. There are a lot of definition but how can I correlate it with real experiences?

## Popular Answers

Light Coherence· Indian Institute of TechnologyPower spectral density function (PSD) shows the strength of the variations(energy) as a function of frequency. In other words, it shows at which frequencies variations are strong and at which frequencies variations are weak. The unit of PSD is energy per frequency(width) and you can obtain energy within a specific frequency range by integrating PSD within that frequency range. Computation of PSD is done directly by the method called FFT or computing autocorrelation function and then transforming it.

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http://www.cygres.com/OcnPageE/Glosry/SpecE.html

## All Answers (28)

Andrea Aprovitola· Scuola Politecnica e Delle Scienze di BaseNirav Desai· Institute of Electrical and Electronics EngineersNirav Desai· Institute of Electrical and Electronics EngineersAndrea Aprovitola· Scuola Politecnica e Delle Scienze di BaseNirav Desai· Institute of Electrical and Electronics EngineersAndrea Aprovitola· Scuola Politecnica e Delle Scienze di BaseNirav Desai· Institute of Electrical and Electronics EngineersNirav Desai· Institute of Electrical and Electronics EngineersNirav Desai· Institute of Electrical and Electronics EngineersNirav Desai· Institute of Electrical and Electronics EngineersNisha Bhatt· Amrapali Group of InstitutesNirav Desai· Institute of Electrical and Electronics EngineersNisha Bhatt· Amrapali Group of InstitutesNisha Bhatt· Amrapali Group of InstitutesDaoud Berkani· National Polytechnic School of AlgiersFouad Mohammed Abbou· Al Akhawayn UniversityPower spectral density describes the signal power distribution over the frequency.

Aasim Khurshid· Universidade Federal do Rio Grande do SulPower spectral density is distribution of power, and it can be calculated by Fourier Transform of auto-correlation function of the signal. You can test this to better understand. Take a signal/image, find auto-correlation and take FFT, plot it.

Taha A. Ali· Arab Academy for Science, Technology & Maritime TransportPower spectral density function (PSD) shows the strength of the variations(energy) as a function of frequency. In other words, it shows at which frequencies variations are strong and at which frequencies variations are weak. The unit of PSD is energy per frequency(width) and you can obtain energy within a specific frequency range by integrating PSD within that frequency range. Computation of PSD is done directly by the method called FFT or computing autocorrelation function and then transforming it.

http://www.cygres.com/OcnPageE/Glosry/SpecE.html

Daoud Berkani· National Polytechnic School of AlgiersThe power spectral density shows how the energy of a signal is distributed. That can allow us to make some decisions or operations on a considered signal. The important thing is that the DSP can be obtained from the function of auto correlation without signal priory knowledge (Wiener-Khintchine theorem 1929). What makes the valid FT for a signal is random or real.

Ahmed Guerine· Institut National des Sciences Appliquées de RouenHi

I advice you to see these documents. You will find what you need with some examples.

Best regards

Chirag Pallan· Indian Institute of Technology Madraswhen you measure the signal it will be having the various frequency components in it, since the power contained in each signal with different frequency will be different so the psd is the graph of power vs frequency.

also the main application of the psd plot is that it will give the range of the frequency where the power density is high

hope this will satisfy your question

Light Coherence· Indian Institute of TechnologyPower spectral density function (PSD) shows the strength of the variations(energy) as a function of frequency. In other words, it shows at which frequencies variations are strong and at which frequencies variations are weak. The unit of PSD is energy per frequency(width) and you can obtain energy within a specific frequency range by integrating PSD within that frequency range. Computation of PSD is done directly by the method called FFT or computing autocorrelation function and then transforming it.

Go here for more...

http://www.cygres.com/OcnPageE/Glosry/SpecE.html

S. Bali Reddy· Indian Institute of Technology GuwahatiPower spectral density function shows the energy with frequency. It will useful when you want check the signal is week or strength.

Yves Chapron· Alpine Institute of Environmental DynamicsWhat is the difference between a PSD = f( Hz) and the square of energy (E^2) = f(Hz)?

When a domain in Hz is changing in energy (increase of E^2) maintained along all the signal following. In other words what is the difference in the meaning of density (PSD) versus only the square of E (E^2) = Hz?

What is lost in the information relatively

Ahmed Guerine· Institut National des Sciences Appliquées de RouenHi

Power Spectral Density ou PSD is the square of the Fourier transform module, divided by the integration time T (or, more strictly, the limit as t goes to infinity of the mathematical expectation of the square of the Fourier transform module signal - this is called average power spectral density). Thus, if x is a signal X and its Fourier transform, the spectral power density is:

PSD=ІXІ^2/T

Best regards

Sumit Balguvhar· Indian Institute of Technology DelhiPSD means how the strength of a signal is distributed in the frequency domain.

Yusuf Adinegoro· Queensland University of TechnologyI have the a similar question, I'd like to add more questions, anyone had experienced to analyze the from Z-accelerometer to PSD and road roughness (IRI). Thanks

Can you help by adding an answer?