Questions tagged [signal-analysis]
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1,385
questions
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12 views
analyzing experimental seismic signal Vs real time seismic signal in graph
I am trying to analyze this graph on this link .On this link the they told us about real time seismic signal are more complex then experimental seismic signal but
" it shares many physical ...
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1answer
23 views
Removing vocal but retaining all background ambient noises
I have one audio file containing human speeches, a lot of ambient noises like audience laughter, birds chirping, sounds of natures etc..
Now I want to separate it into two audio files where one ...
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33 views
Autocorrelation function of a signal [closed]
Lets take a signal such as
$$X(t)=A\cos(t+\Theta)$$
where A is Rayleigh(2) and theta is uniform distribution (0, 2pi). How do you proceed to get the autocorrelation function from this signal? This is ...
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0answers
27 views
Python Time-Frequency Peak Filtering
I am very new to python and attempting to use the Time-Frequency Peak filter on a noisy. To begin I am trialling my code with a noise free signal. I have not reconstructed the signal yet. My question ...
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0answers
12 views
Phase concentration for a broad range of frequency over time
I have local-field potential signals from two animals and I am trying to do phase analysis on these signals. What I am interested in is how phase concentration (or interatrial phase coherence) changes ...
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2answers
51 views
how can we align wto signals with a time lag in between?
I have two signals from two different sensors. I cropped the area i am interested in from both sensor signals. The problem is that the signals start at different time instants. I am searching for a ...
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40 views
pressure decay filtering
So, I've been dealing with a series of pressure decay curves from a pressure transducer. Each one has a waterhammer effect as a consequence of shutting down pumps. Here are examples of 3 curves:
I'm ...
0
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2answers
34 views
Length of DFT defines whether I see the harmonic or the dominant frequency
I have a number of signals that are periodic. I use an fft transformation to obtain the dominant frequency of each signal. In order to increase the frequency resolution I zero pad the signal before ...
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0answers
20 views
I want to calculate the output of this system when the single pulse signal, δ (t), is applied to its input [closed]
how can I calculate the output of this system when the single pulse signal, δ (t), is applied to its input?
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22 views
What does it mean by input and output impedance in a signal generator? [closed]
I have a Lock-In amplifier that can generate sinusoidal signals up to 1.5V peak. There is an output port and input port, and I can obviously fix the frequency or amplitude of the signal I am sending ...
0
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1answer
31 views
How to measure algorithmically side lobes in real data
I want to measure algorithmically the following parameters in a given FFT data (real numbers).
peak side lobe levels
side lobe levels
side lobes nulls
The following image illustrates parameters I ...
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26 views
I want to invert my fourier transform components to waves again
Hi I am using R to analyze some data
I basically did fft(data) and got a vector of complex numbers but from that now I want to remove certain harmonics from my actual wave but how do I convert one of ...
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5 views
control points and concentration of sampled points in a parametric curve
Can anybody explain to me what the following sentence means?
"In cubic Hermite, as any parametric curve, the control points density reflect in the concentration of sampled points in more dense parts ...
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1answer
21 views
I have the following accelerometer signal, I want to segment or slice the signal into Red parts and Green parts
I want to count steps which are basically represented by peaks in the signal. the red part in the signal doesnt correspond to any walking activity, I want to ignore them. Any help on segmenting or ...
2
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1answer
55 views
How to obtain an envelope of my mas-spring damping curve?
I have my program for mass spring system made with Euler method...and I can't menage to obtain envelope of the BLUE damping curve. Can you help me?
...
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2answers
24 views
Using the traditional instruments for measuring high frequency signal
All we know that we can not use the probe for measuring the high-frequency signal (microwave signals). I still can not understand the reason. I have read that the reason because of the wavelength size ...
2
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1answer
31 views
Sample & Hold: Estimate jitter delay of an ADC
I've got a question regarding the effects of sample and hold.
My input signal is $x$, and my output signal $x_{SH}$. The error between the signals is $e_{SH} = x_{SH}-x$.
The sampling frequency is ...
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39 views
Conversion from counts to dB
I have a sound signal, recorded by a hydrophone, which units are counts. I would like to convert the counts into dB re uPa (Decibels relative to microPascals), is that possible?
2
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1answer
73 views
Impulse response of a transfer function
Lets say we have a transfer function from an LTI-system that goes as follows, and we want the impulse response for it:
$$\frac{10\cdot e^{\left(-\mathrm{i}\right)\cdot \pi\cdot f\cdot 8}}{5+\mathrm{i}\...
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2answers
52 views
Estimate “speed” of repeating signal pattern
I have a digitized signal containing a repeating pattern. One could call it periodic, but the time for one period is not constant. The "speed" with which the period is advanced can change over time. ...
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0answers
48 views
Phase response of an LTI-system
I've got an LTI-system such as follows:
$$y'(t)+{2} y(t)={5} x(t-{3}), t>0,
\\ \\ y(0)=0 \ \text{ ja } x(t)=0, \ t<0.$$
From this i've already figured out the transfer function:
$$H(f)=\frac{5\...
2
votes
1answer
66 views
One Too Many Non-Zero Eigenvalues in MUSIC DF Algorithm
I'm working on simulating the MUSIC algorithm in MATLAB to determine the azimuth angle of arrival of a simulated signal. My virtual antenna array consists of 4 antennas arranged in a plane.
While I ...
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0answers
52 views
Convolution of a non-symmetrical window function by a cosine signal in the frequency domain
A have a time signal:
The associated DFT spectrum of this signal:
The time signal can be considered as a non-symmetrical rectangular window function multiplied by a cosine signal with a frequency $...
0
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1answer
32 views
duty cycle of a WiFi Packet
I am doing a simple over-the-air(WiFi 802.11a) test in a shielded chamber involving one Tx and one Rx (around 5 feet).. I need to find the duty cycle given the length of the payload (in bytes), MCS ...
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0answers
20 views
How to normalize features after windowing for future test data?
I have an eeg data about 10 minutes.
I want to extract some features (e.g. statistical features, power spectrum features, interchannel features, . . .) from this data to apply them to the machine ...
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0answers
14 views
In an automotive ECU application for STM32, what ADC modes should I use? [migrated]
I am writing an application for the STM32f407-Discovery board that will use the ADCs present on it. I want to have access to all 17 of the input channels, and I will be using the HAL library to write ...
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30 views
FFT frequency-magnitude not correct when a positive gain EQ point is applied
I have a measurement system, which applies a log sine sweep as stimulus to a DUT and records the return signal.
I then extract the impulse response, and perform an FFT on this to examing phase and ...
0
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0answers
13 views
What wavelet should i use to analyze harmonic function?
If i have the following signal:
$$
s(t) = cos\left [ t\cdot \left (\frac{a}{2}t+b \right ) \right ]
$$
What is the best family of wavelet to analize the signal, and what is its scale range?
Do i ...
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2answers
71 views
The sum part of the formula for a signals power
$$P_x=\lim_{M\rightarrow \infty }\frac{1}{2M+1}\sum_{n=-M}^{M}\left | x[n] \right |^2$$
I have used this formula to find out the powers for different signals, but the sum part of the formula still ...
0
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0answers
9 views
Noise sensitivity of the (classical) Empirical Mode Decomposition routine
I tried to apply a MATLAB Empirical Mode Decomposition routine to denoise a signal, basically retaining only the last IMFs, with a criterion based on the mode energy.
To validate the routine, I have ...
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0answers
16 views
GCC-PHAT for Multiple Sound Sources
Can GCC-PHAT be used to detect multiple time-delays (that is, having multiple acoustic sources simultaneously)? The documentation for the gccphat(sig,refsig) ...
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25 views
Hot to generate image through Delay and Sum algorithm
I want to generate image through Delay and Sum algorithm. The list of the formula are attached, I have calculated rij(t) which is nothing but signals in time domain (1xn matrices), and the tij(x,y) (...
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0answers
21 views
how to reduce signal noises
I am trying generate guided waves on simple metallic plate through piezo-ceramic material, I place two piezo on the surface of the plate at the different location and through Arbitrary pulse generator,...
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0answers
53 views
Rigorous proof of the convolution- Sum Representation of LTI Systems
We've started learning LTI systems and I have confusion regarding the convolution sum representation of a system.
My problem stems from insufficient mathematical formalism in signals and systems ...
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0answers
48 views
State of the art for automatic rhythm analysis
What are the currently most used and less error prone algorithms in the field of music information retrieval for beat detection and tracking?
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32 views
Are there methods to measure how the change in one signal will affect another signal?
I have two distinct signals and I would like to compute their correlation. However, I think that just computing the crosscorrelation does not work here, since the signals are from different sources — ...
0
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1answer
32 views
How to make signal smooth using filter?
I have measured the output of a mechanical system and obtained the signal shown at the attached image. I want to make it smoother by removing the chattering (I think it is called chattering). In order ...
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0answers
20 views
What is DAB modulation in signal generators?
I am using R&S signal generator and for generating a DAB signal there is an option for mentioning the modulation level in %. For example, we can generate DAB modulation 50% . I can understand that ...
2
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2answers
103 views
What is the autocorrelation of a Dirac pulse?
What is the autocorrelation of $x(t) = \delta(t)$?
Can you explain to me how to calculate it?
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0answers
17 views
Time series without a fix frequency
I have readings of almost 400 sensors and the storage system only records when there are variations in sensor readings.
Normally for a certain time (it's stored in days / hours / min and sg) I only ...
0
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1answer
50 views
with given Sampling rate, what max frequency human voice can be captured?
I'm new to signal processing and sampling rate, I was asked interview question related to this.
This is the exact question asked:
With 8Khz of sampling rate, whats the max frequency that human ...
3
votes
1answer
55 views
Square wave FFT results show frequency that seems too low?
I have created an open source plotting package for a low cost oscilloscope - see link here: GitHub Plotting Software
But during my testing I have one result that may be wrong: a noisy 7 kHz square ...
1
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1answer
46 views
Convolution Integral of Harmonic Signal (Cosine) with the Sinc Function
I was asked to show that this convolution integral results in the answers also given in the image. Not quite sure how to approach this integral, everything seems to be coupled together.
Does anyone ...
6
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3answers
3k views
How can a signal be both periodic and random?
Do any examples of such signals exist where the signal is both periodic and random? Because as I see it, if a signal is periodic then the randomness kinda goes away because you know what the signal ...
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0answers
8 views
Optimizing a heating/cooling system for a particular input
Lets say I have a house with 2 rooms. One of them has a window that opens and closes T periodically. So the heat influx behavior of the window is like a square wave. There is an air conditioning unit ...
2
votes
1answer
74 views
Initial Rest Condition for LCCDE causal LTI systems
I am self studying Alan Opennheim's course Signals and Systems. I am a math major and have no background in EE.
I understand that for a LCCDE system to be linear its auxiliary conditions must be 0.
...
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0answers
36 views
Underwater acoustic channel is giving me a flat BER vs SNR curve
I need to do OFDM and GFDM signal transmission in underwater acoustic channel. I have my underwater acoustic channel as follow.
...
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0answers
13 views
How to do colour map in MRI?
For this question,
I assume if we do a colour map, it is based on the magnitude of the magnetic strength?
After that how do we know where each coordinates belong to? Like for example at p= 0 degrees,...
2
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2answers
41 views
Dominant Frequency Peak Decreases with Increasing Window Size
I have a signal that looks like this.
I analyse it using fast Fourier transforms to identify the frequency with the largest peak, which is always close to zero. (There are no other clear peaks.) If I ...
0
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1answer
124 views
DC Spur in DAC output
I have a design in which a signal from ADC is filtered and then played by DAC. In FPGA the real signal is converted to quadrature using DDS with 70 MHz frequency. After filtering, the baseband signal ...
