Questions tagged [signal-detection]
The signal-detection tag has no usage guidance.
433
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Related to Additive white Gaussian noise (AWGN)
In my research work regarding wireless communication, I came across many research papers wherein AWGN is assumed to be modelled as "complex Gaussian with zero mean and unit variance".
I ...
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How to implement maximum likelihood (ML) detector in MATLAB?
Consider the MIMO system which has $N_t$ antennas at transmitter and $N_r$ antennas at receiver and uses Generalized space shift keying (GSSK) modulation. The received signal is given by:
$$Y = H X + ...
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How to express random signal in MATLAB which is transmitted from transmitter to receiver
I am trying to model a random transmitted signal between transmitter (source) to receiver.
Specifically, the transmitter has $N_s = 1$ antenna and receiver has $N_r = 2$ antennas.
My query is that I ...
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Sinus Pattern analysis
i have 1000 data which range between 50 and 180 ( heart BPM data in a day) how can i measure its similarity to a Sinus pattern?
for example, for 20th recorded data (for example it is 60BPM), evaluate ...
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Is there a reason why wavelet in continuous wavelet transform are symmetric?
I have looked at several packages to do continuous wavelet transform (cwt), and the usable wavelet families that are available are always symmetric. Is there a reason for that? The kind of signals I ...
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What books describe convolutional neural networks for DSP?
(note: I read the site policy and meta questions about whether such a question is ok. I will be specific)
I am looking for books that specifically cover using convolutional neural networks (CNN) for ...
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Onset time determination of fast pulse
I am looking for the most precise way to determine the onset time of a
very fast pulse sampled at 5 GHz coming from a physics detector.
Here is an example of my signals:
I already tried different ...
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Phase rotation compensation in AOA
We are using $4 \times 4$ corehw antenna array with nrf52833 mcu as the receiver and nrf52833 as transmitter. When working on AOA Direction Finding, we found that each element in the antenna array has ...
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Which probability density functions to use in a likelihood ratio test for the radar detection problem?
I am trying to understand the radar detection problem in the form of the generalized likelihood ratio test and am having a little trouble with understanding the noise distributions. Perhaps this will ...
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Understanding the modulation concept
In my research work, I came across the concept in the paper
Y. Hu, P. Wang, Z. Lin, M. Ding and Y. -C. Liang, "Machine Learning Based Signal Detection for Ambient Backscatter Communications,"...
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How to evaluate pairwise error probability and detection in presence of gaussian noise?
I am reading Digital Communication Systems by Simon Haykin and I am stuck at one point.
Consider a two-dimensional signal space that has a message constellation of four points, given by $s_1,s_2,s_3,...
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MMSE for channel estimation
I am learning about the MMSE detector and how to implement it.
I looked at some example codes on the Internet but many of them directly use the perfect channel when calculating the MMSE estimated ...
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Is using cross-correlation with a reference wavelet a good approach for vibration detection?
This is my first time actually applying signal processing to a real problem.
I'm trying to monitor some equipment for vibrations. The vibrations aren't constant but occur at some point in time - I've ...
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Optimum Measurement of Sine Wave Amplitude in Noise
There are many related questions posted about estimating sine wave parameters, and this one is closest: Measuring amplitude of a pure sine wave of known frequency close to the noise floor, but none ...
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Measuring amplitude of a pure sine wave of known frequency close to the noise floor
What I want to ask you comes from a place where I can play with all the parameters as much as I want (I can measure as long as I want and as fast as I want, as well as change sensor/ADC).
The signal ...
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Identify abrupt changes in an audio waveform
I have an audio file which was created by substituting multiple speech segments into an original utterance.
I want to find the timestamps where such substitutions happened, so I guess that one thing I ...
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Understanding Maximum likelihood detector expression?
Consider the MIMO system which has $N_t$ antennas at transmitter and $N_r$ antennas at receiver and uses Generalized space shift keying (GSSK) modulation. The received signal is given by:
$$Y = H X + ...
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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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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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Finding start point of a curve
I'm currently working on a project where I have to measure the latency of a given system.
Below you can see a exemplary image which shows the input pulse (green) and the response (blue).
In order to ...
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Best 'SNR-like' detection statistic for time series signal in the wavelet domain?
What is the best way to define a detection statistic for a time series event trigger generator, which computes the wavelet transform of some time series data? I want such quantity to be similar to 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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135
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Should we use Maximal ratio combining and an equalizer together?
I have confusion on MRC(Maximal Ratio Combining) method which I would like to clarify. An example is where I have 1 transmit antenna and 4 receive antennas. The concept of MRC is to combine all the ...
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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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Performance Effects of Dropping ADC Least Significant Bits before DSP processing (Besides the Obvious)
What would be the effect of dropping LSBs of an ADC on the performance of a DSP system apart from the obvious reduction in dynamic range. For example if there is a 14 bit ADC and only 10 bits are used,...
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Detector for vector-valued signals
I'm trying to find the optimal probability of detection/false alarm for the following detection task. Given $N$ signal samples with $d$ dimensions (independent channels) each, assign the samples to ...
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Can we detect WiFi from Spectrograms using signal processing?
I'm looking for some suggestions on detecting wifi using spectrograms (abs magnitude only) . My project involves a wifi driver which outputs a spectrogram whenever it scans the channel .
Can we use ...
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Amplifier Placement in a Wireless Receiver
In the context of wireless receiver system design, what is the optimum choice of amplifier placement? Should the received signal be amplified first then filtered or should it be the other way round?
...
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802
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How to decide whether a recording contains a signal of interest?
I am currently implementing an acoustic communication system in Matlab. For synchronization purposes, every transmission contains an upchirp preamble. The receiver uses cross-correlation to find the ...
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Issues with playing and recording a square wave sound on the same PC
I am learning signal processing. For a hobby project I wanted to transmit and record a simple ASK signal via my soundcard, to see if I can write code to recover the sent data. After playback and ...
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SNR ratio in radar for stationary targets
Is there a mathematical model which provides relationship between the Signal to Noise Ratio in radar measurements and velocity/range of targets. i.e.
How SNR varies with the speed of targets?
How SNR ...
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How to synthesise an approximate 'pulse' waveform from an observed section of a similar waveform
Following on from my previous question, kindly answered by @peter-k, I have a related one...
I have, in a small interval $a \leq x \leq b$, a function $q(x) := q(x;\rho,\gamma)$ whose exact form is ...
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How to identify sudden changes in signals?
There are instances when neural networks, after being trained continually on a subset of data, tend to drastically lose their performance. I've attached an image below depicting the same. I am looking ...
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How best to detect an unknown number of pulses of an approximate known form over an interval?
It is approximately 30 years since I last studied signal processing, but have lately encountered a problem for which I am confident the solution is well-known in the signal-processing world. I hope ...
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AWGN continous time channel + colored noise
I'm working on an exercise but I'm stuck at the question where the noise becomes colored, can someone help me ?
Let $\{\psi_1(t) = \mathbf{1}\{t \in [0,1)], \psi_2 = \mathbf{1}\{t \in [1,2]\}\}$ be an ...
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Filter type selection for signal envelope detection
Working on a signal envelope detection code in Matlab in which an RF signal envelope is to be created. The flow is such that filtering is performed according to the detected presence of a signal in a ...
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Why would the emitted signal from repeating binary data over a wire appear at a frequency lower than the bit frequency?
I have a signal over which binary data is transferred over wire in a repeating 10 bit format. The wires that the data is send over are CML, DC coupled 3.3V twisted pairs, and the protocol of encoding ...
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Related to SNR when the channel is in the form of vector and matrix
In my system model there is a sensor (transmitter) with $M$ antennas and receiver with $Q$ antennas. The received signal expression is
$y_q(n) = (h_q+\textbf{f}_q\textbf{G}$)$s(n)$+$w_q(n)$----(1)
...
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How to detect that a waveform is of the same type if it has a different frequency (Example: Sinwave with 2Hz and another with 10Hz)?
I am trying to detect whether a received waveform is a Sinusoid, Square Wave, or any other. How should I go about doing this, if the signal frequency can be different every time?
I have looked online ...
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What are the differences between GPS and GLONASS?
I'm studying the localization systems, especially the GPS one. I inquired about other systems and wanted to understand what are the main differences between GPS and GLONASS, why has the first type ...
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A Machine Learning Based Algorithm as an Alternative to the Matched Filter
Consider we have to detect a known signal added with Gaussian noise. In this scenario, the matched filter is known to be an optimal filter for SNR. The question: is there any machine learning ...
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About the process to convert basedband signal into passband
Theoretically, the passband $y(t)$ signal equivalent into baseband signal $x(t)$ is given by:
$y(t) = \Re \begin{bmatrix}
x(t) e^{(-i2 \pi f_ct )}
\end{bmatrix}$
where $\Re$ represents the real part.
...
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Algorithm to detect tapping-events in an XYZ-signal of an accelerometer
How do I find signal-sections with a re-appearing particular shape in a noisy signal?
I want to detect tap-events (user tapped a device) using the 100Hz 3-axis accelerometer data provided by the ...
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Advantages of Chan's method over the Kalman filter
For a 3-receiver tracking system. Chan's positioning method gives an exact solution to the location problem. However in the literature, I saw that one could use the extended Kalman filter which is ...
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Problem to extract value from complex_to_mag_squared GNURadio block
I am trying to dissecate a large bandwidth into smaller ones and, for each of those smaller bands, see if it contains enough energy to consider that a message is sent in it. To do so, I am thinking of ...
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Methods to increase FFT time resolution without lowering FFT size
It is known that in FFT time and frequency resolution are inversely related if FFT resolution is increased then time resolution will decrease. However is it possible to overcome issues in time ...
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Detecting whether the signal is increasing intensity or decreasing intensity
I am trying to determine whether the signal is increasing intensity, decreasing intensity, fade-in, fade-out or peak using an audio file. The graph has an x-axis with time and a y-axis with the data. ...
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Calculate number of buzzs and their duration
I'm trying to calculate the number of buzzs and their duration from a buzzer. I'm working with python and scipy lib and the short time fourier transformation capturing the audio with a microphone.
To ...
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Extract specific frequencies or wavelength out of a recorded audio sound
I have a audio recording piece of an environment that contains multiple sounds, is there a way to separate the different frequencies or wavelengths of this signal with Python or matlab?
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How whip antenna even work if they don't have two terminals? [closed]
I understand antenna should have two terminals to emit radio waves like this:
But in whip antenna it has only one pointy terminal, how does it work?
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