Questions tagged [signal-analysis]

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23 views

Spatial frequency and video frequency of an image

in my lecture notes about image sensors (CCD, precisely) I have read the following statement: The transfer function $F(\omega)$ of the image sensor is related to its spatial resolution function $F(\...
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22 views

Extracting rms delay, delay spread, and CIR from power delay profile

I have a spread spectrum channel sounder running the following transmitter and receiver: When running it over the air (~2km), I get the plot of the correlator output: I can see that there are peaks ...
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2answers
262 views

Threshold for peak detection of noisy signal in frequency domain

I have a noisy signal (Gaussian Noise) with a known SNR and known Noise variance. This signal contains a number of Frequency components. My ultimate objective is to detect the components of the signal....
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2answers
39 views

Sine Dipole formation using two hydrophones

I am trying to do MATLAB simulations for generation of SINE Dipole using two hydrophones spaced distance 'd' apart for signal coming from direction 'DOA'. The MATLAB code is given below. The confusion ...
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2answers
481 views

Why does the addition of noise improve coherence between two signals?

Taking a simple example of the coherence between two signals, each composed of two sinusoids of frequency 100 and 200 Hz, I expect the coherence to show two peaks in the spectrum located at precisely ...
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1answer
21 views

Power Spectrum analysis arbitrary length signals

I have signals belonging to diseased and healthy samples recorded from multiple electrodes. These signals are taken monthly and are of arbitrary length (say 4-5 mins). I am planning to do a power ...
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2answers
68 views

Can an audio recording tell whether it is made in a large or small room?

The conversation of one or more people will be analyzed. I think need to look for something similar to reverberation or echo in an audio signal. How can this be implemented? Update: small room is ...
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4answers
12k views

Simple and efficient algorithm to detect frequency and phase of a sine signal

I need an algorithm to detect frequency and phase of a pure sine signal. The frequency of the input signal changes between 0 and 100 Hz. The value of the signal gets captured with a frequency of 20 ...
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2answers
172 views

Prove that, in DFT, Upsampling in time domain is equal to replication in frequency domain

Given: $x[n]$ is an $N$-point sequence whose DFT is $X[k]$ $$x[n]\xrightarrow{\mathcal{DFT}} X[k]$$ then, Prove that: DFT of the same sequence after insertion of $(M-1)$ zeroes between successive ...
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22 views

Calculate the percentage of accuracy with which user made the assigned sound

I want to design a web-app for my cousin who is 2 years of age in which i have implemented a functionality in which when an image is clicked some sound gets played and the user has to make the same ...
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1answer
62 views

Use of I/Q representation for unmodulated Rx Signal

it may be a stupid question but while learning about DSP and Modulation I was wondering, if the I/Q representation of an RF Signal is of any use, when the received signal does not contain any ...
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1answer
40 views

Phase difference between two wave files

I am doing comparison between two wave files, How to calculate phase difference between those files? Second wave is generated by making some changes in the first one .I have tried calculating phase ...
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17 views

RMS and RMQ from PSD

From acceleration data I made a Power Spectral Density (PSD) and calculated the RMS via: $$a_{RMS} = \left[\displaystyle\int_{f_1}^{f_2} a_{PSD}(f) df\right] ^{\frac 12}\tag{1}$$ Now, I want to ...
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1answer
16 views

Plotting a Time Frequency contour/colormesh plot of a Discrete Wavelet Transform

I have a pressure vs time data of a noise on which I wish to perform discrete wavelet transform. I have divided my frequency range into 1/3rd Octave Bands and have calculated sound pressure level at ...
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31 views

Can largest-triangle-three-buckets downsampling method used with fourier transformed signal?

I've been reading on the largest-triangle-three-buckets downsampling method for downsampling. Though it was originally published in the thesis "Downsampling Time Series for Visual Representation&...
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1answer
32 views

Different number of modes while performing the EEMD (Ensembled Empirical Mode Decomposition)

I am performing an Ensemble Empirical Mode Decomposition (EEMD). I wrote a MATLAB routine to perform the EMD. I noticed that when adding white Gaussian noise to the input signal, sometimes I obtain a ...
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1answer
41 views

What is the purpose of dividing an audio signal into segments and analysis each segment?

I read bunch of materials for extracting feature from audio signal and they all tell me to break signal into segments, why don't we analyze all the audio signal? I don't know what are the advantages ...
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24 views

For an LTI system, the zeos and poles are defined in the z plane. How to add additional poles and zeroes so LTI system is real valued?

The question already has a zero and a pole in the complex plane. It is asking to add additional zero and pole so LTI becomes zero valued. zeros=-1/2 + 1/2 i , poles = -1/3 -1/3 i . What I understand ...
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1answer
40 views

Frequency Domain Distribution

I have a complex signal in the time domain normally distributed. What will be its distribution in the frequency domain? I assumed since the frequency domain is a linear transformation the distribution ...
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1answer
118 views

A-weighted Digital Filter for 1/3rd Octave Band Analysis

I want to do a 1/3rd Octave band analysis on a noise signal. But the sound pressure levels should be in dB(A), i.e., and it should be A-weighted. For this, I am using the A-weight function from this ...
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1answer
282 views

Wavelet transform and FFT using to extract feature power bands with EEG signals

I am using 5 channels [ fz , cz , c3 , c4 , pz] to detect drowsiness of driver My First Question is, what is the right input to get feature power band ( Theta , alpha , gamma , beta ) to wavelet ...
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33 views

Normalize two or more sound signals in order to let them with the same duration time and amplitude

I am very new in signal processing area and I am trying to solve the task in order to make an experiment with audio files from different languages, so, I am trying to let some ogg audio files with the ...
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11 views

Mobile jammers mitigate EMF or merely block signal? [closed]

Shall a jammer abase the frequency or just block signal and have the same attenuation reading regardless of the cell jammer?
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1answer
23 views

What is the driving Voltage?

While I was looking into ultrasonic transducer in order to transmit and receive a beam, I came across specification of a transducer stating driving voltage as 20Vrms. I am not sure what actually does ...
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3answers
74 views

Meaning of sampling frequency?

Say there is a communication system, which can manage sampling frequency up to 4 MHz (given by software). Can the system be able to process signals with maximum frequency more than 2 MHz? Because ...
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23 views

How to deal with different audio formats for audio classification?

I am working on an audio classification problem statement to classify between two audio classes. I have collected samples from jotform, they are providing audio widget to collect .wav audio but it ...
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1answer
30 views

What is the actual format of this audio file?

I am collecting some data from jotform .wav widget. All the audio files are in .wav format. But when I tried to open the file using python ...
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1answer
31 views

Accelerometer sensor's data analysis [closed]

Here is a sample data that I got from the accelerometer sensor: The first selected area shows the acceleration of the IMU device to right side and the second shows the movement to left side. I am ...
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0answers
84 views

Signal Acquisition Game?

I read from Wikipedia that signals obey the uncertainty principle. The product of the measured uncertainty in frequency times the measured uncertainty in time is greater than a constant. The ...
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1answer
87 views

Question about eigendecomposition, signal subspace and their properties

Lately, I am readig a paper titled A Subspace Method for Estimating Sensor Gains and Phases. In it, it is mentioned: There are $m$ sensors in the array, $n$ known narrowband far-field signals($m \...
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24 views

RMS of signal vs average amplitude

I am trying to estimate the average amplitude of some signal with frequency 6 Hz, sampled at ~300 Hz. See figures for a part of the signal and its dft calculated using matlab. I estimate the average ...
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1answer
38 views

Phase difference calculation between two wave files

I am doing comparison between two wave files, How to calculate phase difference between those files? Second wave is generated by making some changes in the first one .I have tried calculating phase ...
0
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1answer
29 views

How to classify audio files based on their ZCR, energy, and enthropy of energy features?

Let's say I wanna classify the audio files of race car exhaust and normal car exhaust. I attain few features such as ZCR, energy and enthropy of energy from the training set and I wanna build the ...
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46 views

How to obtain exponential decay peaks from damped signal in python? [closed]

I have a signal where I would like to implement a peak detection algorithm where it only collects peaks that follow exponential decay behaviour and stop at a certain height. Here is an example of a ...
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39 views

When are MLSE (with Viterbi algorithm) equalizer used in real life (only for equalization)? [closed]

The complexity of a MLSE decoder (with Viterbi Algorithm) is in the order of $M^L$, where $L$ is the length of the channel and $M$ is the order of modulation. My question is in what circonstances, it ...
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1answer
131 views

CIC Filter implementation for Normalized Correlation

This is a follow-on to the original post ... I am trying to implement real-time correlation of two signals. I noticed the CIC Filter discussion here: How to find correlation/cross-correlation of two ...
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17 views

Separation of a delayed mixtures of signals

I have three emitters in three different positions that emite three signals $S_1(t), S_2(t), S_3(t)$ with $$S_1(t)=S_2(t)=S_3(t)$$ Two receivers recive $R_1(t), R_2(t)$ with \begin{align} R_1(t)&=...
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0answers
70 views

Separating/recovering base signal from two mixed signals, given phase information

I have collected two signals, $B_1(x)$ and $B_2(x)$. The signals start and end at the same $x$-values. Each signal $B_i(x)$ contains: a base signal $b(x)$, which is the same for both, and a signal, ...
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1answer
26 views

what is the relationship between the reliability of a monte carlo test and the length of the samples tested and the number of errors found?

Considering this setup, single tone transmission over a channel impaired by AWGN, doppler spread, and inter symbols interference. We are to compute the BER as a function of the SNR. We want to find ...
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1answer
20 views

Having Problem about DownConversion

I hope, you are doing well. I want to ask question about baseband conversion. Background: I generated two AM signals in MATLAB, which one of them is shifted in time. I multiply the signals with $\cos(...
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1answer
68 views

Continuous wavelet transform

Continuous wavelet transformation has been quite widely used for various applications. Most of the papers that I found were using CWT for non-stationary signals. Can we use CWT for stationary signal ...
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1answer
18 views

deconvolving a 1d signal using a lookup table of “PSFs”?

assuming I measure a signal that has different PSFs per position in time. for example: ...
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19 views

Threshold Estimation from a Linear FM Pulse Position Modulated signal

I have a signal chain to detect multi channel LFM (Linear Fm - Hann window being applied as shaping filter for the pulses) pulses as shown in picture below. (Numbers in the picture is in Hz., for ...
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1answer
35 views

channel estimation based on time-domain pillots

I am confused if it's possible to estimate the channel based on the time-domain pilots. I mean I have such signal $x$ with length $N$ after taking its $iFFT$ we get $X = ifft(x)$. I have perfect ...
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1answer
43 views

What the disadvantages of up-sampling

Let's say we have a signal $x[n]$ upsampled at the transmitter by $4$ and then downsampled at the receiver by $4$ too. As known, the performance will be much better compared with transmitting the ...
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3answers
142 views

Signals - question due to sampling

I don't have an idea how to start it. Help pls :) $$m = z(t) + \frac{\operatorname{Sa}(t-T)}{4}$$ We have some signal $z(t)=\left(\operatorname{Sa}(\frac{t}{T})\right)^2$. How often the m signal ...
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1answer
408 views

Power Spectral Density of discrete White Gaussian Noise defined with variance and sampling interval

From Creighton and Anderson Chapter 7 on Gravitational Wave data analysis: Please explain where the delta t and the limit came from in this derivation.
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22 views

Why filtic function does not work for a specific use?

And how can I solve this issue? I designed a filter via bilinear transformation in order to obtein a high-pass filter of Butterworth. When I want to set initial conditions with filtic function, it ...
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2answers
189 views

Down sampling an EEG signal

I have a set of 10 minute EEG signals that were sampled at 400 Hz and have 16 channels which corresponds to a 16x240000 matrix. These EEG signals belong to two different classes. I am trying to ...
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1answer
55 views

Why use PSD to analyze a signal instead of its Fourier Transform?

Let's imagine I have a perfectly known signal $s(t)$ and I want to analyze its frequency components. I noticed that mostly everyone would use the PSD of $s(t)$ to do that, instead of simply use the ...

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