Questions tagged [signal-analysis]

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18 views

Low pass filter with desired non linear phase

How should I design a low pass filter with a desired non-linear phase.
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1answer
34 views

Converting IQ to RF data [duplicate]

I appreciate any help: I wanna convert IQ data to its RF data, representing an image. The center frequency and sampling rate are available. What I do is: First I do up-sampling in MATLAB by applying ...
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1answer
49 views

Maintain constant total amplitude of sum of sines

Given a set of N sine waves, each with their own amplitude and frequency, is there a straightforward way to select their phases such that the sum over all sines maintains a constant amplitude, given ...
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28 views

Why my result from FFT which is negative frequencies are different from positive frequencies

I am trying to analyze a signal from monkey brain by applying FFT on the signal. By using numpy.fft.fft function to perform Fourier Transform on raw signal, I got the power of frequencies in the ...
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32 views

Frequency contour detection in spectrogram

I have an image of a spectrogram and I wish to detect the tracks/contours of prominent frequencies present in the spectrogram. In the end, I want to be able to get various prominent curves from the ...
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0answers
23 views

Flicker Frequency for taking snapshot of monitor [closed]

When a snapshot of a monitor with refresh rate 60 Hz is taken with a camera with rolling shutter config operating at 30 FPS, what is the expected flicker frequency in the resultant image? I took ...
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0answers
35 views

IQ to RF conversion [closed]

I appreciate any help: I wanna convert IQ data to its RF data, representing an image. The center frequency and sampling rate are available. What I do is: First I do up-sampling in MATLAB by ...
0
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0answers
10 views

EEG signal dataset info

So I wanted to use pre processing on EEG data obtained from BCI competition 2005 dataset iiia which is a multiclass dataset. This data has lots of info on it but i cant seem to obtain/get data other ...
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1answer
34 views

Hand written DFT vs MATLAB FFT has flipped conjugates?

I had to compute the DFT of a signal with 5 points with a hand-written method and using MATLAB's FFT just to see if they are equal. Taking the absolute value of both gives the same spectrum, however ...
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1answer
28 views

How to add a particular noise on a signal?

I have a simple ADC model (an input signal == sampled signal ). The adc should be modelled as with following values: 1.5 V (peak to peak).. meaning --> +1.5 V --> 0 dBFS ... how to do this ? The ...
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0answers
25 views

Decomposition of a non-stationary signal

Suppose $f(t)$ is a non-stationary signal which can be expressed as follow: $f(t) = A_1(t)\text{sin}(\omega_1t) + A_2\text{sin}(\omega_2t) + ... + A_n(t)\text{sin}(\omega_nt)$, where $0 \leq t \leq ...
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16 views

Convergence of LMS

I'm not really sure about the following question and don't know where exactly to look it up, so I'm asking here: I have an adaptive filter and compute the coefficients iteratively using e.g. LMS or a ...
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14 views

Basic in frequency-selective channel: part with decoding

Here I have asked about the basic of the theory of frequency selective channel and the user @Florian explained to me how to compute precoding in such case using the effective channel. I am just ...
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1answer
33 views

Non-coherent discriminator

I'm reading a paper about designing a non coherent discriminator for GNSS receiver. I came to the equation I'm not sure about that symbol < how would I write this in a small pseudocode ? for ...
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1answer
54 views

machine learning on multiple signal at once

I am very new signal processing and I am asking this with the expectation that someone gives me a concrete guideline on how to approach my problem. The problem I need to solve is that I have 2 ...
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1answer
45 views

RF signal identification algorithms

There exist many, many analog and digital data transmission protocols. It is often difficult to tell which mode one listens to and tedious to do for many signals. In Ham Radio, a Reed-Solomon ...
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37 views

Summing RMS Values

I'm trying to calculate the RMS of a signal whilst only having access to the current RMS values of the waveforms making it up. This is because I need to calculate the total RMS so I can use it to ...
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0answers
13 views

What is the difference between robust stability and robust performances for a MIMO system subject to uncertainty?

I am studying control systems and I am focusing on the case where uncertainty is present in the system. I have seen that in this case I have to be able to garantee robust stability and robust ...
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17 views

How to check significance of a channel? [closed]

I have a Brain signal which is multi channel. I want to check if which channels are significant for that specific task. How can I check this? Suppose, I have a multichannel EEG data-set of Alzheimer ...
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1answer
52 views

Problem in verifying zero blocking property of a zero of a multiple input multiple output system

I have a multiple input multiple output control system, and in particular a two inputs two outputs system. I want to find the zero state direction and the zero input direction of the system, which has ...
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1answer
41 views

Is it possible to use a control scheme with a delay as prefilter?

I am studying control systems, and in my studies I have encountered the topic of control scheme of the form and I have seen thaht this control scheme is really useful since it is possible to add a ...
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1answer
47 views

A Delay Between Two Filtered Chaotic Signals

it is a common practice to use a shift of cross-correlation peak to evaluate a group time delay of two signals (chaotic signals are included). Can one synchronously and equally filter these chaotic ...
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1answer
25 views

How to express time delayed discrete signals

Hi sorry this question might sound silly but, a signal $$x[n]=[ 6 \: 4\: 0\: 2]$$ what is $$x[n-2]$$ then?
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8 views

How do I design a reference filtering control scheme with a lead compensator?

I am trrying to design a lead compensator for a system. I have the following control scheme: where $Cr(s)$ is a prefilter which can be a lag or a lead compensator. My obkìjective is to design $Cr(s)$....
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11 views

Why does the step response has higher overshoot if the zero is too slow in a lead compensator used as a prefilter?

Consider a control scheme of the following type: where $C_r(s)$ is used to filter the reference, and it can be a lead compensator of a lag compensator. One thng I don't understand is why if I ...
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1answer
65 views

y(t) a of an integrator circuit

I have a signal $$ x(t)= \frac{1}{T} e^{-\frac{t}{T}} u(t) - \frac{1}{T} e^{\frac{t}{T}} u(-t) $$ and I know that it transits in a integrator circuit and I have to find y(t) in time and frequency ...
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2answers
24 views

Extracting different frequency bands (alpha, beta, gamma) from brain activity data

I am new to signal processing and despite googling about my question, I still couldn't find the solution. I have an Electrocorticography (ECoG) dataset. This consists of recording brain activity from ...
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1answer
42 views

Fit Rice Distribution for negative RSS

I measured the Received Signal Strength in dBm between a receiver $R_x$ and a transmitter $T_x$ at different distances $d_1, d_2, \dots, d_n$, and all the values that I obtained are (of course) ...
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2answers
42 views

Meaning: channel unknown and known at the transmiiter

What does "channel unknown" and "known at the transmitter" mean? In books about signal processing, it has always mentioned it if capacity or transmission (estimation) is discussed. I can't understand ...
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0answers
39 views

Measurement inaccuracy

Does this measurement result comply with the specification or not? Why? The upper limit of a test is 50 m/s and your measurement result is 46.912 ± 10 m/s. The lower limit of a test is 5 mT and your ...
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17 views

Calibration the instruments

The Measurement systems and instruments are frequently calibrated. Do anyone know the reason behind different calibrations. I have read that the measurement uncertainty increases with every step in ...
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0answers
26 views

Acceleometer Noise and FFT

Background: I'm fairly new to signal processing and sensors, etc. I'm working on my thesis, which involves the use of an MEMS acceleration sensor as a vibration measuring device (for rotating ...
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2answers
65 views

Inverse Fourier transform Of a triangular impulse

I have to find the expression of this graphic and after find the inverse Fourier transform of it. First of all I found that the expression of the graphic is $$ X(f) = \frac{1}{2} tri (\frac{f+f_0}{B}) ...
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1answer
40 views

Discrete Fourier Transform in Signal Processing - Interpreting graphs of transformed signals

Given above are the real parts of the signals I to IV. Which of the following statements are correct? (i): Signal III is the result of the discrete Fourier transform of signal I. The associated ...
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22 views

Cannot reconstruct constant overlap add STFT perfectly

I am implementing an STFT function for spectrogram of certain audio files. Here's my function: ...
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1answer
36 views

How to generate IQ samples of a signal?

I am using a HW with LMS7002 RF transceiver chip. This chip takes IQ values as an input. 1. Can anyone point me to a sample IQ value generator? That I can use to test. 2. What will be the IQ values ...
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0answers
53 views

Power spectral density vs. Fourier Transform

I am trying to understand the difference between the Power Spectral Density and the Fourier transform. Specifically, I am trying to understand why the power spectral density is useful and in what ...
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1answer
20 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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1answer
37 views

Step-by-Step calculation of stationary wavelet transform gives shifted results?

Good morning, I am doing an SWT by hand to understand it better, and have a couple of questions. Maybe someone here has experience with this? I am using the book "Conceptual Wavelets" by Fugal, ...
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0answers
29 views

ADSR parameter identification from envelope data

I'm trying to work out how to identify (or predict) ADSR parameters (attack time, decay time, sustain level and release time) from envelope data of real signal (or 'raw' data, but I think getting it ...
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0answers
50 views

GPS CDMA signal acquisition (BPSK modulation)

Sorry, this may be a rookie question: I have a CDMA gps communication in BPSK. Codes have a duration equal to $1\ \text{ms}$ and their length is 1023. At the carrier frequency ($f_c = 1.57524\ \text{...
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0answers
28 views

FSK carrier frequency estimation in non equiprobable data

We know that in equiprobable data,change in phase over a time interval, this result will be directly proportional to frequency: f∝Im(s(n)s(n−1)∗) Where s(n) is the normalized complex FSK time domain ...
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0answers
24 views

How to tell, which coefficient corresponds to which frequency while computing wavelet transform?

I am applying wavelet transform on functional Near Infrared Spectroscopy (fNIRS) signal. My aim is to get the info that which coefficient corresponds to which frequency in the signal. Is it possible ...
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1answer
30 views

Total Harmonic Distortion THD for the rectifier

I have a circuit with rectifier and this cause the non-linearity and consequently harmonic. I show it on the oscilloscope and then collect the signal from the oscilloscope to the computer by using the ...
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0answers
31 views

Strange signals in wifi channel

I am currently working with a USRP B200 mini-i to receive 802.11 signals from various usb wifi devices. When sending packets with the USB device over a channel, lets say 2.412GHz, i can't really see ...
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3answers
56 views

How to find the time of beginning of the slope of the signal?

I have a time signal in MATLAB format. Sampling rate is 100k, so it is roughly 5 seconds of signal. See the link below https://www.dropbox.com/sh/v7vev2j14i77mlk/AAA-X7JGMAzO6IyElYmFPFwra?dl=0 If ...
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2answers
54 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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0answers
38 views

Signal Detection in Real Time Sensor Data

Exploring some robust and ingenious methods/algorithms of detecting certain peaks in a signal. For example: The two pictures are the same, the area of interest is just highlighted in the second ...
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0answers
27 views

Radar signals features for machine learning

I have project in which I have to classify materials based on the spectra of received radar signal. I want to create feature vectors of the specific materials. Can anyone share his ideas. ?
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0answers
27 views

How to create different Time frequency images from a data

I'm new to Python. I have a time series in a CSV file that has about 5000 rows and 3 columns. I have split the data into training and testing in ratio 70:30 respectively. However, I have a problem ...

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