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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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 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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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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How to Extract Nonorthogonal PCA Principal Components
My problem is essentially a 'blind source separation' problem. I have 3 non-orthogonal sources (or basis functions) and $N$ random linear combinations (mixes) of said sources. My problem is to obtain ...
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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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Why HRV is considered as "irregularly time-sampled sequence"?
HRV is heart rate variability. As far as I understood, it is the time interval between two consecutive R peaks in the ECG signal. So an HRV dataset may contain two columns, one containing the interval ...
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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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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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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
$$\Lambda_n=\{y\in C_{2\pi}: \mathcal{F}(y)[k]=0 ~\...
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How can I check similarity of two different sinusoidal waveform model?
I am trying to establish a similarity index for two different signals. These signals are quite different in amplitude and signal length. Their waveform is sinusoidal, and frequencies are at a close ...
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Deriving the IF phase equation of FMCW
My understanding of the FMCW was limited to one chirp and was mostly focused on frequency analysis. (Mostly built upon this answer)
I wanted to expand my understanding to multiple chirps and was ...
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Why are the units of a sampled signal Volts*Hertz?
I'm posting here because I don't understand why when we have a signal, let's say a voltage, the units of its sampled values are Volts multiplied by Hertz and not just only Volts? It's something I've ...
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How to perform an operation on a signal which depends on 2 variables?
How do we perform DFT when the input signal depends on 2 variables (like in a image the color of the pixel depends on both $x$ and $y$)
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Range-Doppler Coupling in FMCW
I did some derivation of the IF signal of the FMCW using sawtooth LFM.
A chirp with sawtooth LFM is expressed like below
$$x_T (t)=\cos\left(2\pi f_c t + \frac{\pi}{T}B (t-mT)^2 \right)$$
Where, $f_c$ ...
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Energy ratio of signal
What is the energy ratio of signal at frequency domain?
What is its mathematical formula at frequency domain and what can stand for?
I found it in this paper
https://www.researchgate.net/publication/...
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Decomposition of $H(z)$ as maximum-phase, minimum-phase
The frequency response is:
$$H(z) = 2-7z^{-1}+7z^{-2}-2z^{-3}$$
I see that it has $3$ zeros: $z_{01} = \frac 12$, $z_{02} = 2$, and $z_{03} = 1$; and $3$ poles in: $$z_x = 0$$
Now, I have to write ...
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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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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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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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USRP Frequency Drift Measurement
I trying to measure the frequency drift between two N210 USRPs using GNURadio Companion.
I used one USRP as a TX and the other one as an RX. The transmitted signal is a complex sinusoidal.
The issue ...
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Maximum possible CFO that can be estimated
I was trying to model the CFO (Carrier Frequency Offset) estimation in MATLAB.
The Frame I was working on is of the following structure, yellow being the information data.
How CFO was introduced?
...
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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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Finding the maximum frequency deviation and phase deviation
I'm trying to solve a problem regarding communication and I'm stuck. The questions asked me to find the maximum frequency deviation are usually written in cos or sin wave. But this question isn't, so ...
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Real time FFT - Wouldn't zero-padding a signal at the end distorts the output?
I have looked at previous similar questions, but I am still not very clear on this. Most real-time or otherwise fft functions suggest adding zeros at the end of the input to make the sample size an ...
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How do you find the null to null bandwidth for the signal below?
My tutor does not explain it very well. Can someone please explain to me the reasoning and what null to null bandwidth actually is?
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Separating 'signal' from periodic 'noise'
I have data in which the signal we want is a few gaussian peaks superposed on a noisy background in which some of the 'noise' is periodic. Simply suppressing the associated fourier modes is effective ...
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Origin of the definitions of 16 types of discrete normalized/non-normalized Sine and Cosine transforms
I am a Ph.D in pure math. In the literature of signal processing, I observe that 16 types of discrete normalized/non-normalized Sine and Cosine transforms are being extensively studied. They have some ...
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Discrete Time Signals - Time Scaling and Time Reversal
On the top graph, we can see a discrete-time signal $x[n]$.
I don't understand how for the signal $x[3-n]$, the impulses with magnitude $1$ still are at the positive indices $n = 1, 2, 3, 4$. Why ...
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What is inverse Fourier transform of real spectrum?
I am trying to retrieve the origin signal in time domain (or path-length domain) from a spectrum obtained by CCD-matrix of interferometer.
I understand how to transform a real signal in the time ...
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VNA based calibration of RF equipment relative to discreet time domain measurments
I am looking for methodology on how to correct data for losses present in RF signal paths.
The basis for my objective is to convert an discreet time domain signal into the frequency domain with an FFT,...
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What is the secrecy rate?
I read several papers on physical layer security that explain several methods to maximize the secrecy rate. However, I didn't find a very clear definition about the secrecy rate. What is it? How is it ...
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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 <...
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The normalization of the autocorrelation function and how it changes the definitions you've learned about signal analysis in communication systems
Since this question is book-oriented, I will kindly ask you to accompany it with a book that is considered by many researchers the bible of Digital Communication: Proakis - Digital Communications, one ...
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Why is ARMA preferred instead of AR?
ARMA basically is an AR model which considers past inputs to the filter as well. But what is the benefit of taking past inputs to the filter if we are considering real-time processes which are all ...
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Jerk detection in accelerometer data
I want to detect jerk from accelerator data i.e. values beyond 1.57 m/s^2, but due to the high frequency nature of the sensor (400 values per second), it gives multiple jerks instead of one.
How can I ...
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What does the signal of $y(n) = x(n^2)$ look like?
The original signal is at a) in the image below, and I'm confused as to what the exponent on the dependent variable does to the signal, so can anyone point me to where I go wrong and how do I actually ...
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Represent a sinusoid by other sinusoids of different frequencies
Can a sinusoid with unknown frequency be constructed from other sinusoids with known frequencies? Are there any theorems for this problem?
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How do you save / convert an image to be in the (complex) frequency domain?
Quick Note: I don't believe this is a subjective question... however if it is I will gladly modify to be more objective
In ImageJ, if I take the FFT of an image, how can I save this new frequency ...
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Significance of poles in a Transfer Function
Sorry for asking this basic question, but I am new to signal processing and have this doubt for a long time.
I have been studying signal modelling and have
$$H(z) = B_q(z)/A_p(z)$$
where $A_p(z)$ ...
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How can I get a single object's audio response from a pair of colliding audio?
Problem and backgroud
Two objects $A$ and $B$ are colliding and produce audio response $x_{AB}(t) = x_A(t) + x_B(t)$, where $x_A(t)$ and $x_B(t)$ are audio produce by these two objects individually.
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Detecting and Removing Noise from Signal using Python
Through this platform, I want to ask that how can I remove unwanted noise from the signal when you do not have much information regarding the frequency at which they appear? Data is collected from an ...
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Construct complex signal from a real-valued time series and Hilbert transform
I have a time series measurement $v(t)$ from a physical nonlinear system and its power spectrum $E(f)$ look like the following
From a theoretical point of view, the solution of the system is modeled ...
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How to normalize Loudness on different Android Smartphones playing same audio simultaneously?
I have been working on a conference solution based on a smartphone grid. Right now, I am stuck on Android Smartphones. Although I have managed to normalize loudness programmatically when it gets ...
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What is the difference between Yule Walker and Modified Yule Walker Equation that used in Stochastic Signal Modeling?
Our Professor couldn't explain the clear difference between the Yule Walker equation and the Modified version of it that is used in Stochastic models. Please explain both the equations and why we ...
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Calculate noise variance from a given SNRdB
I was analyzing the following code for the MRC scheme from the book MIMO-OFDM Wireless Communications with MATLAB. Here, I am not able to understand based on what logic the sigma value calculated <...
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