Questions tagged [signal-analysis]
The processing of signals for the purpose of extracting a parameter or property embedded in a signal. Signal goes in and far fewer numbers come out.
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I need to compute the FFT and plot the spectrum and I do not know my sample frequency and signal length
I am new to matlab.
I have a noisy dataset represented as a signal on which I have to compute the fft and plot the one-sided spectrum, however I'm quite unsure if my data's signal length I assume that ...
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Is there a formal definition of what it means for a signal to be sparse?
Up to now I've never found a rigorous or a formal definition of what it means for a signal to be sparse other than it means that it has a relatively low number of non-zero entries or that the ...
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digging into a signal
I am a civil engineer and I have a research focused on InSAR Data.
I have a basic question about analyzing the signals, please.
How can I dig into the signal I have?
Is there any code to define the ...
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What are the modes of a transform basis?
So, I'm reading Steven Brunton's book, "Data Driven Science & Engineering", and I'm trying to understand what he means by mode in this following excerpt:
Most natural signals, such as ...
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Kalman filter in data fusion
I am very new to Kalman filter. I am doing a project using one sensor the track the sensor's position. I developed 2 methods to solve the position, one in better accuracy and one is less accurate.
I ...
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Time shifting a signal in python
I am currently modeling FMCW (linear FM) and SFCW (stepped FM) chirps in python. For my project, I need to simulate those signals as a transmit chirp and a received one, scattered from point targets ...
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Generate a pulse with Tukey window [closed]
I am trying to generate a pulse of the shape
with the following parameters.
Carrier frequency is 5 [GHz]
Pulse Repetition Interval is 1600 [ns]
Pulse Width is 100 [ns]
Rise Time is 8 ns
Fall Time is ...
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Issue with SNR and SINAD Measurement using Matlab Functions in specific cases
I have a MATLAB code in which I need to calculate the SNR and SINAD of received signal at known frequency (assumed as tone signal). The issue is that sometimes the power at that frequency is lower ...
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Stepped Frequency Modulated Waveform Continuity issues [duplicate]
I want to generate a stepped frequency modulated waveform (SFMW), similar to a linear frequency modulated chirp.
While approaching this, I wanted to consider the issue that there should be some ...
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Clipping detection algorithm for a sinusoidal signal with noise and unknown amplitude in an online fashion
My problem is the following:
I am sampling data from a sine signal
Samples come in a online fashion (more and more data incoming through time).
The device does not have a lot of memory so it is ...
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Extract PVC feature from singal to train the ML model with PVC characteristics
I have ML model which is trained on Afib, Normal, Other - 3 class. Currently when I am testing the model with unseen database, sometimes it identify PVC singals as Afib class.
For example -
enter ...
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how to find type of a binary sequence
I want to know how I can find the type (algorithm) of a binary sequence at hand.
For instance, I'd like to know whether the following (binary) sequence is m-sequence, Barker, Gold, etc.
AC DD A4 E2 F2 ...
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undecimated wavelet transformation
I have 20kHz sampled dc current data of 3 second (i.e signal length of 60000). I want to use undecimated wavelet transform to extract statistical features from it. But i don't know how to choose best ...
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Inverse continuous wavelet transform, how to obtain fluctuations at a given scale with ssqueezepy?
How can I obtain the fluctuations of a timeseries at a specific scale using the ssqueezepy library for inverse continuous wavelet transform (ICWT)?
I have a minimum reproducible example that uses the ...
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How to be sure that we chose the correct sampling rate in practice?
Let say I perform an experiment and I record data at a given frequency sampling $F_s$ and then I perform FFT analysis on these results.
As I do not know the characteristics of the perturbation that I ...
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How to characterize unknown perturbations in practice ? FFT analysis?
I want to analyze the motion X(t) of a very flexible structure, which is excited/forced by unknown perturbations, in order to characterize this perturbations.
Hence,...
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Comparison of WVD vs STFT Spectral analysis in the presence of Noise
This question is an extension to the question about WVD vs STFT originally posted Here. During the QA it was pointed out that the WVD only works for noiseless signals.
To test that out I created a ...
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Practically Calculating Cramer-Rao Lower Bound
What is the method to compute Cramer-Rao lower bound for a particular application. For example I have an application in which FFT of an incoming signal is performed to get a Coarse estimate and then ...
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How to figure out or estimate the level of noise in a given data distribution
I have been given a data distribution which was synthetically generated by geostatistical methods such as variogram analysis. Without having the source of the technique which generated the data, is ...
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How we determine type of filter with pole(s), zero(s)? [duplicate]
Let's say we have this Laplace transform:
$$H_{1}(s)=\frac{1}{(s+1)(s+3)}\;, \; \Re{e} (s)>-1 $$
So, we know that there is a poles at $s=-1$ and $s=-3$.
With these informations, we found that to be ...
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Bode Plot - Why we add dB value in some situations?
Question: Specify the straight -line approximation of the Bode magnitude plot: $$H(j\omega) = 0.04 \cdot \frac{jw+50}{jw+0.2}$$
I don't understand that in the plotting part we add 6dB for two ...
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Wigner-Ville Distribution (WVD) vs STFT for Spectral Analysis
What are the Pros and Cons of using Wigner-Ville Distribution for spectral analysis of a signal vs taking the STFT. When is it appropriate to use one over the other and is WVD used in real-time ...
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Signal Reconstruction Using Scipy.signal.cwt
Can someone explain to me how I can reconstruct a signal using the scipy.signal.morlet2?
The codes in the link only allows one to do a fourier transform using the morlet wavelet, but there is no such ...
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OFDM channel estimation using the transmitted signal multiplied with a matrix
I have OFDM system, where the modulated signal $x$ with length $N$, and $N$ is the number of subcarriers in OFDM symbol. $x$ is multiplied with a well-known unitary matrix $G \in N \times N$ before ...
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Understanding the signal to noise ratio (SNR)
In my work, I came across the following expression of signal to noise ratio (SNR) which contains expectation operator.
The received sampling vector is
$\textbf{y}(n) = \textbf{h}s(n)+\textbf{u}(n)\tag{...
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Why the frequency variation is negative in the curve of instantaneous frequency vs time for the faulted phase current?
I am working on the analytic signal concept for observing the frequency variation in the faulted phase current waveform in MATLAB/Simulink model. In MATLAB/Simulink model, I have used analytic signal ...
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Why there are spikes in instantaneous frequency vs time plot of an analytic signal?
I am working on the analytic signal concept for observing the frequency variation in the faulted phase current waveform in MATLAB/Simulink model.
In MATLAB/Simulink model, I have used analytic signal ...
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How can I correlate two noisy voices in order to enhance their result?
I have an array of two microphones, spaced out, which continuously transmits audio input to a central processing unit. There is a slight delay between them, which is sometimes variable because they ...
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Noise Applied to OFDM Subcarriers
Assume we have an OFDM signal received with AWGN + phase noise. Then, we extracted some subcarriers after the demodulation. Now each subcarrier $Y_l[k]$ includes a noise component $Z_l[k]$ according ...
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Is it possible to find the FFT of a 1024-point signal by taking 8-input points at a time and calculating the FFT of those 8-points until the end?
Suppose the input signal has 1024 samples, and I want to take a 1024-point FFT.
Can I instead take the 8-point FFT of the first 8 input samples then another 8 samples and continue this till the end?
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Decoding binary data from temperature / rain sensor
I have the following data from a generic rain gauge / temperature sensor captured using an Arduino validated against raw data captured using Audacity.
Similar to this question Decoding of binary ...
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Can we control the maximum norm of a continuous signal whose finitely many Fourier coefficients are fixed?
Let us denote $C_{2\pi}$ by the set of all $2\pi$-periodic continuous signals $x:\mathbb{R}\to \mathbb{R}$.
Fix $n\in \mathbb{N}$ and put
$$\Lambda_n=\{y\in C_{2\pi}: \mathcal{F}(y)[k]=0 ~\...
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Signal sawtooth decomposition
I'm interested in analyzing a windowed signal in terms of a weighted sum of sawtooth waves. Being a somewhat DSP newbie, is there an obvious approach to this? I realize that sawtooth waves don't form ...
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How can I check similarity of two different sinusoidal waveform model?
I am trying to establish a similarity index for two different signals. These signals are quite different in amplitude and signal length. Their waveform is sinusoidal, and frequencies are at a close ...
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Deriving the IF phase equation of FMCW
My understanding of the FMCW was limited to one chirp and was mostly focused on frequency analysis. (Mostly built upon this answer)
I wanted to expand my understanding to multiple chirps and was ...
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Based on the eigen structure, What applications of discrete sine/cosine transformations can be found?
I am a PH.D in mathematics. I am interested in finding some applications of discrete Sine/Cosine transformations (DTTs) that are based on the eigenvectors.
I have found some results concerning ...
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How to perform an operation on a signal which depends on 2 variables?
How do we perform DFT when the input signal depends on 2 variables (like in a image the color of the pixel depends on both $x$ and $y$)
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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 ...
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Range-Doppler Coupling in FMCW
I did some derivation of the IF signal of the FMCW using sawtooth LFM.
A chirp with sawtooth LFM is expressed like below
$$x_T (t)=\cos\left(2\pi f_c t + \frac{\pi}{T}B (t-mT)^2 \right)$$
Where, $f_c$ ...
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Energy ratio of signal
What is the energy ratio of signal at frequency domain?
What is its mathematical formula at frequency domain and what can stand for?
I found it in this paper
https://www.researchgate.net/publication/...
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Finding delay between two sensors measuring two phenomena
I have two sensor data with noise, a moving object's GPS position and acceleration data. It's known that there is a delay between the data. How do I find this delay?
I have no prior knowledge of ...
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Relationship between energy, power and sampling rate?
Excuse my silly question, but I think the energy increases as the sampling rate increases. In the time domain, the number of samples increases so the energy increases; In the frequency domain, ...
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Steering Vectors and Bluetooth Low Energy for computing Angle of Arrival
I am new to signal processing, but I have background in mathematics. I am trying to use Bluetooth Low Energy (BLE) on three mobile devices, where one device is being tracked and the other two act as ...
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Question about constructing orthonormal wavelet bases
Consider multi-resolution analysis and the two-scale equation for $\phi(t)$ and $\psi(t)$ given in
$$\phi(t) = \sqrt2\sum_{n}h_0[n]\phi(2t-n)$$
$$\psi(t) = \sqrt2\sum_{n}h_1[n]\phi(2t-n)$$
is it ...
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Why does this recorded signal have two waveforms in it?
I have recorded the two words "Stop" and "Go" in the waveform. There is an orange waveform and any normal assumption would be the noise picked up by the receiver, but my professor ...
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Phase Measurements of OFDM Signal with USRP
I am doing some analysis on a received OFDM signal using USRP N210 with GNURadio. Figure OFDM RX shows the OFDM receiver (please refer to GNURdaio workshop slides) . The transmitted OFDM signal is ...
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Correlation and ratio between two signals?
I have two signals $x$ and $y$ (blue and red one)
the Pearson coefficient between them is 0.9659
The yellow signal is the ratio: x/y*mean(x)
The two signals are ...
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Method for splitting time-sampled signal into two signals
Update: the yellow area in the graph below can be ignored, it shows power produced. I'm only interested in the blue line, and how to separate power consumed by the heating system from the rest.
I have ...
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Understanding FFT output oscillation around y-axis
I am looking at the output of the FFT and trying to understand the meaning of the real and imaginary parts of the output.
My signals (real in time) are comprised of tonal peaks and the magnitude of ...
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