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0
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1answer
25 views

What is the best Algorithm to estimate the frequency for Almost-Periodic Data or complex periodic data?

I’ve got what it looks like a periodic signal but the periods seem not equally repeated, I want to estimate the PSD, particularly I need to obtain the dominant frequency of this data. I’ve estimated ...
0
votes
0answers
30 views

How to obtain Power Spectral Density (difference between RMS)? [on hold]

I did a fft but i need to do the PSD of certain frequency range, how can I do it and whats the difference between this and RMS?
0
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0answers
25 views

Welch's Overlapped Method

I am measuring wind speed using a number of different anemometers. These anemometers are placed on a structure which exhibits sinusoidal motion. Thus, the signal of the anemometers contains both the ...
1
vote
0answers
61 views

What is the best method to estimate the frequency(PSD) for noise signal

I’ve been trying to estimate the frequency of a signal I obtained at 1000Hz sampling frequency. The dominant frequency is expected to be not more than 4 or 5 Hz. I’ve estimated the PSD using ...
0
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0answers
22 views

Can uneven sampled points generate valid PSD and spectrogram?

My recording device samples signal at 100 Hz. At each sampling point, it generates 512 values (I assume due to non-ideal impulse in practice, so each impulse is actually a window with certain width ...
0
votes
1answer
27 views

Effect of number of data segments in Periodogram-based PSD

In Welch or Bartlett method, original signal is divided into L segments, of D overlapping (D=0 in Bartlett method). Then FFT is done for each segment, and the result is the average of all segments' ...
1
vote
1answer
114 views

Is the periodogram squared-magnitude DFT or squared-average DFT?

How is the periodogram defined? I have been searching the internet a lot, and I find two different definitions: periodogram is the squared magnitude of the DFT periodogram is the squared average of ...
0
votes
1answer
37 views

What's the number of data points in a Welch-based PSD?

In Welch periodogram Power Spectral Density estimate, we devide the N-long signal into K segments, each of length L with overlapping D, such that N=L+(K-1)*D. In this paper, just above eqn (7), the ...
1
vote
1answer
126 views

Calculating the Power spectral density

I've already asked this question on SO, but didn't get an answer, I tqake a shot here. I am trying to get the PSD of a real data set by making use of fftw3 ...
0
votes
1answer
65 views

Will using window in Welch's method introduce artificial peak in estimated PSD?

I'd like to estimate the power spectral density of the signal attached here, the sampling rate is 100 Hz. If I don't do windowing (i.e., use boxcar window), the result seems to be a simple $1/f^2$ ...
0
votes
0answers
64 views

PSD Estimation: Welch's method with median averaging

I would like to use median averaging when making a PSD estimate via Welch's method. I notice that this is available as an option in R welchPSD, but not in SciPy or Matlab (in which the default is mean ...
3
votes
2answers
211 views

PSD estimate using FFT - scaling and units

I know that similar questions have already been asked – I have read the answers, yet I am still not sure if I understand the topic properly at some points. I want to use FFT to calculate PSD ...
1
vote
0answers
38 views

Importance of phase of time-series for PSD

I have $m$ complex-valued time-series $z_m(t_n)$, which I am currently analyzing. I started by calculating their PSDs and CSDs. These exhibit an unexpected peak at a given frequency, which is present ...
3
votes
1answer
82 views

Only random signal has PSD?

I heard from someone online who said: "Only random signal has PSD, determinate signal does not have. For example, period signal does not have PSD." I am very astonishing about this statement, but it ...
0
votes
2answers
124 views

What can we deduce about variance when we are given the noise spectral density?

Given the noise spectral density ${N_0\over 2} = a$, what can be deduced about the variance? In the case of a two-symbol canal(/cable), and when $T_0 = 1$. Is it that, $\sigma_X^2 = {N_0 \over 2} ...
-1
votes
1answer
52 views

PSD of a 100 1kB packets with equally probable 1s and 0s

SO i have to calculate the PSD of mentioned input. here is my code. (every little thing written wholly and solely by myself) ...
1
vote
1answer
223 views

PSD - Is this formula correct?

Trying to understand whether or not I am calculating the PSD correctly. Below is the equation that I am using: $$ PSD_{rms}(f_{m} = m \cdot f_{res}) = \frac{PS_{rms} }{ENBW} = \frac{2 \cdot \left | ...
2
votes
1answer
79 views

PSD - Correct Formula for removing Noise

Ok, so finally some things are making sense. I'm trying to scale the results, which I have done by the following equation: $$ PS_{rms} = \frac{2 \cdot \left |y ...
2
votes
1answer
188 views

PSD - Spectrum analysis

Could someone tell me where it is that I might be going wrong with the following problem? Ok, so I'm computing a spectrogram, and, trying to return the PDS of the signal (to show where the signal ...
0
votes
1answer
1k views

Power Spectral Density estimate (PSD)

I'm trying to understand PSD, and, it's functions. So far I have carried out the following: Segmented a signal with NFFT = 256 and ...
2
votes
0answers
73 views

How to properly express periodogram over analog frequency?

Assume a signal $x[n]$ with $N$ samples and its $N$-point FFT $X[k]$. Assume also the simplest power spectral density estimator: $$ S_x[k] = \frac{\left| X[k] \right|^2}{N} $$ With this estimator, ...
0
votes
1answer
63 views

Downsampling a PSD that was generated by zero-padding - worth it?

Let us say we have a signal $y(k)$ that is of length $K$. I can compute its PSD, also of length $K$. Let us say that this length was not good for finding peaks, so I computed a PSD that was of length ...
1
vote
1answer
1k views

Wavelet Transfrom + Power Spectral Density (using Matlab)

I don't have background knowledge about signal processing before and new at Matlab too. I have EEG data (with noise removed) 1x128; sampling rate = 128 Hz, It's means that I have 1 sec. data right? ...
2
votes
1answer
953 views

Why the RMS of a PSD curve is the root of the area below

I will try to explain what is my level of understanding of this problem, please correct me if I'm wrong: RMS is the Root Mean Square, it represent the mean value of the input signal. PSD is the ...
4
votes
1answer
190 views

Fourier transform of Autocorrelation function, what am I missing here? (Power spectrum)

Given this problem I know that the autcorrelation and power spectrum are fourier pairs, so when taking taking fourier transform of Rxx, one should end up with Sxx However, when I take the ...
0
votes
2answers
105 views

In Search of Voice Activity Detection Algorithms - What happens to the frequency or pitch or speech features as speaker moves away from microphone

Actually i am in search of a Voice Activity Detection Algorithm which could distinguish between voice and non-voice Roughly speaking it must not detect even a bullet sound,even a foot stepping and ...
0
votes
1answer
118 views

Compute PSD from a CSV file

I'm sorry if my question might be simple, but I don't have a strong background on signal processing. I have a csv file of a 8 MHz bandwidth, sampled with a resolution bandwidth of 100 KHz. What I want ...
2
votes
0answers
129 views

Is there any problem with my FFT method?

I am trying to analysis a system by Fourier Transform. my system has 3 dominant modes. (1,0.05) (0.51,0.01),(0.46,0.01) the pairs are defined as (freq,damping_ratio) I've got those result with ...
5
votes
1answer
3k views

What is cross-spectral density- CSD?

I asked a question earlier but I didn't get any answer for it. So now I am simplifying it: what are Cross-Spectral Density (CSD) and Power-Spectral Sensity (PSD)? What is their application? How can I ...
4
votes
2answers
1k views

PSD (Power spectral density) explanation

I'm trying to understand how the PSD is calculated. I've looked in a few of my Communication Engineering textbooks but to no avail. I've also looked online. Wikipedia seems to have the best ...
2
votes
1answer
100 views

Guitar String Replucks

I'm analyzing guitar string plucks and sustains. I'm having good success with auto correlation using FFT's. Now I'd like to detect plucks while the string is still vibrating. Since I already am ...
0
votes
0answers
284 views

Getting sound pressure level (SPL) for a frequency band from Welch's derived PSD

I'm using Welch's method (pwelch, in octave) to get the PSD of a recorded sound signal (i.e. pressure level vs. time). I then took the PSD data and took the sum of the amplitude in each octave band ...
2
votes
1answer
894 views

Working backwards from PSD to possible signal

I have been trying to reconstruct a random signal from its PSD and am running into trouble. I know that many different signals in the time or spatial domains can result in the same PSD-- I am ...
3
votes
1answer
632 views

Producing Colored Noise from a given PSD Data

I need to estimate (extract/produce) the colored noise of a given PSD Data. I have the following procedure to get the desired results. First of all I calculate the filter coefficiencts using firls ...
0
votes
2answers
224 views

PSD of Windowed signal

Suppose PSD of a signal $x(n)$ is $ PSD_{xx}(w)=1$. Now if a window function w(n) of length $ 0\le n \le N-1$ is applied to $x(n)$. what will be the new PSD?
11
votes
1answer
4k views

What is the difference between PSD and squared magnitude of frequency spectrum?

The power spectrum of a signal can be calculated by taking the magnitude squared of its Fourier transform. Being an audio person, the signal of interest for me would be a time series. How does this ...
8
votes
1answer
4k views

Difference between Power spectral density, spectral power and power ratios?

What 'exactly' is power spectral density for discrete signal? I was always under the assumption that taking the Fourier transform of the signal, and then the ratio of desired freq range magnitude over ...
27
votes
2answers
5k views

Why so many methods of computing PSD?

Welch's method has been my go-to algorithm for computing power spectral density (PSD) of evenly-sampled timeseries. I noticed that there are many other methods for computing PSD. For example, in ...