As of May 31, 2023, we have updated our Code of Conduct.

# Questions tagged [power-spectral-density]

The Power Spectral Density (PSD) is the distribution of signal power over frequencies.

774 questions
Filter by
Sorted by
Tagged with
18 views

### confusion understanding/interpreting power spectrum of audio in MATLAB?

Please find attached snapshot. I am confused regarding power spectrum in MATLAB as according to google definition in attached snapshot"the distribution of the energy of a waveform among its ...
17 views

### How can I plot the power spectra of a ST (Stratosphere Troposphere) Radar in MATLAB to estimate the doppler shift

Respected all, I am trying to plot the power spectra of a ST (Stratosphere Troposphere) Radar to estimate the doppler shift. I am able to obtain a 3D plot between range, FFT point and Power density ...
73 views

### Power Spectral Density and Energy Spectral Density are both Fourier transform of autocorrelation?

I've been looking into both of these quantities and feel like I have a good understanding intuitively of what they each represent but according to Wikipedia both the PSD and the ESD can be computed as ...
1 vote
37 views

### Computing Power Spectral Density from FFT vs Welch's method vs Periodogram [duplicate]

I'm looking into different ways to get the Power Spectral Density (PSD) (while toying around with python) of a discrete signal/time series, and I'm struggling to understand why I get (very) different ...
1 vote
82 views

89 views

### Correct Windowing Effect at Amplitude Scale

I am trying verify the noise floor returned by Matlab sinad(). I am able to get the results matching by summing power spectrum density with $\frac{f_\text{s}}{N}$. ...
9 views

### How is received power distributed in partially used channel?

I want to learn how the RSSI is distributed in received signal in an OFDM block. When a UE transmits a signal, assume it allocates certain number of resource blocks (RBs), for instance 10 RBs in 20 ...
1 vote
63 views

### frequency present in FFT but not in PSD

I have a simple $0-40 \texttt{Hz}$ IIR bandpass filter. With pure sine inputs I see $60 \,\texttt{Hz}$ is completely gone in the output FFT as expected by looking at the filter frequency response. ...
19 views

### How to measure synchrony between EEG frequency bands illustrated in PSD values

I am investigating the synchrony measures among EEG frequency bands. However my dataset has only PSD values (in frequency domain). I found out that measures like Granger Causality are good but they ...
17 views

### Generalized distribution of Power Spectral Density at each Frequency Point

I have an expression for the expectation of the power spectral density and I call it $F(\omega, \Theta)$ where $\omega$ is the frequency and $\Theta$ are the parameters. I have some measurements of ...
50 views

### IIR bandpass filter attenuates frequencies within the pass band

I applied Butterworth filters (order=5) that have different cutoff frequencies to a simple signal composed of four sinusoidal oscillations and computed its PSD. <...
1 vote
129 views

### Definitions of Discrete Power Spectrum and Discrete Power Spectral Density

I have been reading lots of posts about the scaling factors in PSD, and related topics on this forum. My understanding of the topic has been greatly improved. Thankyou all. I just need a little more ...
85 views

### What does the covariance of a power spectral density between frequency points mean [duplicate]

I am struggling to understand the meaning of the covariance of PSD (Power Spectral Density) between two frequency points ($f_1$ and $f_2$). The covariance of a function $s(t)$ in time domain $t$ is a ...
100 views

### How to interprete the standard deviation of the psd in dB?

I have done a power spectrum density estimate using Bartlett's method. However, I was wondering if it is also possible to get a sense of the variation of the averaged spectra. I have plotted the mean ...
46 views

### Calculate standard deviation of spectral desity in a Bartlett's method fashion?

I have done a power spectrum density estimate using Bartlett's method. However, I was wondering if it is also possible to get a sense of the variation of the averaged spectra. Unfortunately, I have ...
40 views

### Bartlett's method: Order of normalisation?

I want to estimate the power spectrum of a given signal using Bartlett's method. I understand the general purpose of the method. However, I do not get my head around the algorithmic description of the ...
84 views

### How to calculate a mixer noise?

I am struggling to calculate a mixer output noise, but I am stuck in the understanding how to calculate it formally, could someone please help with reasoning or give a reference? I assume that we use ...
53 views

### Lomb-Scargle or Periodogram for non-uniformly sampled data

I have non-uniformly sampled data and I'm trying to look at its Power Spectral Density (PSD). For that, I looked at the Periodogram PSD estimate of an interpolated (with uniform sampling period) ...
1 vote
203 views

### Does power spectral density change with sampling rate?

The power spectrum $\texttt{PS}$ of a (white noise) signal depends on the frequency resolution, $df=f_s/N$, where $f_s$ is the sample rate ($\texttt{Hz}$) and $N$ is the sample size. The power ...
1 vote
33 views

### Convert MUSIC algorithm to EV

I write some code, but result looks very strange: ...
1 vote
59 views

### Prony method doesn't work

I have used the code from: https://github.com/quantumlib/OpenFermion/blob/v1.5.1/src/openfermion/linalg/wave_fitting.py#L41-L76 try using with my signal: ...
179 views

### Units of 6.02*N + 1.76 as an FFT noise floor

I'm working on estimating the FFT noise floor for a data acquisition system my colleagues and I are designing. I've read MT-001 several times. In general, I think I get it. However I'm a little stuck ...
1 vote
45 views

### The baseband sampling frequency when the negative spectrum is considered

Suppose I have a signal $x(t)$ of bandpass bandwidth of $2W$ Hz. The sampling frequency must be at least $2W$ in baseband, because the largest frequency component is $W$ Hz. I understand that, when we ...
63 views

### Can a large drop in the PSD indicate the presence of a periodic noise?

I was wondering if a large drop in the plot of the PSD of a sensor measurement could indicate the presence of a periodic noise. Here is my PSD: Thank you.
22 views

### EIRP conversion from given value at one polarization to both bolarization when antenna operate at both polarizations

For an antenna that operates in both polarizations, how do I convert its EIRP density, given in dBW/Hz assuming one polarization, to the dBW/Hz value for both polarizations? For instance, if EIRP = -...
90 views

### Compute SNR of a signal with not clear fundamental frequency in PSD

I'm trying to compute SNR from a signal in which by visual inspection I can guess the SNR but I cannot compute it because I cannot find the fundamental frequency of the signal as I should be. On the ...
116 views

### Why can two different signals have the same periodogram?

I have just started trying to self-study an intro course on signal processing. I have just been introduced to the periodogram and have a hard time understanding why completely different signals can ...
85 views

### How to extract human voice from cluttered signal?

I have a signal which has human speech, background voice and noise as it can be seen in below figure. I have calculated its power spectral density (PSD) using many different methods which can be seen ...
1 vote
309 views

### Periodogram (Welch) has different levels depending on length of segment/ resolution

I am trying to compute the PSD of a signal in MATLAB using Welch's periodogram method as shown in the code snippet below. ...
190 views

### In what way does the cross-spectral density of two signals describe their similarities?

I’m trying to gain a deeper understanding of what the cross-spectral density of two signals represents. I know how to compute it, and I know it represents a covariance of sorts, as it appears in the ...
131 views

### Effect of down-sampling to PSD from auto-correlation?

I have a problem to evaluate the PSD from auto-correlation. As you know, PSD is the Fourier Transform of the auto-correlation. But I observe the spur at PSD when I calculate the auto-correlation with ...
90 views

### What happens if you use the Fourier transform of the autocorrelation of a non-WSS process to compute power spectral density?

The Wiener–Khinchin theorem states that the power spectral density of a wide-sense stationary stochastic process can be obtained through the Fourier transform of the autocorrelation of the signal i.e. ...
1 vote
60 views

### What is the meaning of the scaling difference between my DFT magnitude squared plot and my periodogram plot?

I have an EEG recording of duration $2\text{s}$ with sampling rate $f_s=200 \,\text{Hz}$ and, as a mathematician, wish to familiarize myself with some of the standard terminology in signal processing. ...
59 views

### Emperical mode decomposition problem

I am using Empirical Mode Decomposition (EMD) algorithm to decompose a vibration signal generated by outer race bearing defect using case western réserve University data. I am facing a problem: unlike ...
411 views

### FFT of signal data with windowing, overlapping and averaging

This is my first ever question here so the help is really appreciated. I am performing FFT on a signal. I want to perform windowing, 50% overlapping and averaging to the signal. There is a function <...
1 vote
Suppose I have a signal $x(t)$ with baseband bandwidth $W$ Hz and power $P$, and consists of $K$ samples, and I draw the two-sided power spectral density (PSD) of this [baseband] signal in MATLAB as <...