Questions tagged [signal-detection]

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How do I solve this SIMO channel with two receive antennas?

Consider a SIMO channel with two receiving antennas. Slow Rayleigh fading channel is assumed, i.e. $h_1, h_2 \sim \mathcal{CN}(0, 1)$. The channel state information $(h_{1}, h_{2})$ is known at the ...
0 votes
2 answers
173 views

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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1 answer
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MATLAB 2D CA-CFAR not working on range doppler map?

Here is the ca-cfar code below for 2D. the range doppler map cell values are in the form of (abs(amplitude)).^2. For some reason my pfa does not come out as 1e-5 as I have set it to be, instead being ...
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If the signal and the noise term separately are coloured, can the resultant signal + noise be white? If yes, how is it good for signal detection?

Let's say we have a received signal at each antenna of a $n_r\times n_t$ MIMO system - $$r = L_rGs + w$$ where $G$ is the channel matrix consisting of MIMO channel coefficients that are i.i.d., $L_r$ ...
2 votes
0 answers
47 views

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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4 votes
1 answer
109 views

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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5 votes
2 answers
287 views

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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3 votes
3 answers
683 views

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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0 votes
2 answers
57 views

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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0 answers
37 views

Clutter Signal and Target Echo

In passive bi-static radar systems, some researchers consider that the clutter and the target echo are mutually independent. So, they use independent component analysis for clutter suppression/...
1 vote
2 answers
73 views

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 ...
1 vote
1 answer
31 views

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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2 answers
216 views

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 ...
2 votes
1 answer
71 views

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 ...
1 vote
1 answer
32 views

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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3 votes
1 answer
262 views

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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0 votes
2 answers
43 views

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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0 answers
8 views

Preamble detection Threshold calculation [duplicate]

can anyone recommend a good article where I can read how to correctly calculate the threshold for detecting the presence of preamble at the output of a matched filter?
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0 votes
0 answers
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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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0 votes
1 answer
27 views

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 ...
0 votes
0 answers
50 views

Optimal methodology for analysis of noisy 3-dimensional (x,y,z) vibrations data

Details I have x, y and z data of some vibrations and a timeline of corresponding events that caused these vibrations. I want to analyze how events and vibrations are related, so that it can be stated ...
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49 views

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 ...
7 votes
2 answers
706 views

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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0 votes
1 answer
150 views

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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2 votes
1 answer
119 views

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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2 votes
0 answers
41 views

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 ...
0 votes
0 answers
70 views

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 ...
2 votes
4 answers
350 views

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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0 votes
0 answers
31 views

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. ...
0 votes
1 answer
26 views

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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0 votes
3 answers
140 views

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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0 votes
1 answer
40 views

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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-1 votes
1 answer
71 views

what is bi-spectrum of signal

anyone knows what is bi-spectrum and its usage in signal processing? how can I extract data from bi-spectrum of signal? I want to use bi-spectrum of signals to classify them and I want to knows the ...
-1 votes
1 answer
51 views

localization with TDOA under Doppler shift

In a localization system, I use the TDOA (Time Difference of arrival) method. The transmitter is moving at a speed v and its communication signal is received on 3 receivers at different times. For a ...
1 vote
1 answer
385 views

Conversion from phase noise to EVM

I have a phase noise specification for a digital QPSK transmitter at 8GHz (symbol rate 50 Mbaud). From that specification I am able to compute the RMS jitter in radians (47 mrad or 934 fs using the ...
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0 votes
1 answer
95 views

Square Root MMSE

Could anyone please explain how to perform the derivation of the square-root MMSE equation using an extended channel matrix H (as it is said in the "A LOW COMPLEXITY SQUARE ROOT MMSE MIMO DECODER&...
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0 votes
1 answer
50 views

How to detect a long deceleration phase in a signal?

Given the following signal, I would like to keep only the deceleration phase in orange. I have no idea whether there exists techniques to do that or not. I imagine that I can smooth the signal, ...
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1 vote
1 answer
326 views

Range-Doppler Matrix Cells

I am working on developing an understanding on range-gates and the size of each cell. I haven't had much luck in finding information in how the matrix in the image below is generated, so I have some ...
3 votes
1 answer
55 views

Is it possible to detect the sparse vector based on a non-invertible matrix

Given a non-invertible matrix $X \in \mathbb{R}$, let's say that matrix is, e.g. : $X = \begin{bmatrix} 0.7500& -0.2500 &-0.2500 & -0.2500 \\ -0.2500& 0.7500& -0.2500 & -0....
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2 votes
2 answers
136 views

The transmission distance of a signal

I am no professional in this area so please forgive me if this question is too immature. And thanks in advance for any help and information. I want to know how to calculate the transmission distance ...
1 vote
1 answer
58 views

Cross-correlation for delay estimation in acoustic signals

iam doing BPSK transmission and receiving with acoustic signals, in order to get my actual signal from my received signal I am using xcorr in matlab to find peak point of alignment and getting my ...
0 votes
1 answer
174 views

Periodic signal detection algorithms?

I am currently working on pulsar signal periodicity detection. Most of the literature which i studied used traditional FFT (Fast Fourier Transform) or (Epoch Folding) techniques to find the ...
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1 vote
1 answer
52 views

Beep Signal for Latency Calculation

I want to play audios on two mobiles with sync. But mobile phones are not in sync. I am trying to find two Mobile phones playing latency so I can pad latency on each phone so they can play together. ...
1 vote
4 answers
553 views

What algorithm can I use to compare two signals' similarity?

Suppose I have two time series (measuring the gyroscope data from two body sensors — A and B). I somehow need to evaluate whether the signal B is "following" the signal A — that is, how ...
-1 votes
1 answer
227 views

Faster way to Implement a CFAR (window average) Threshold

I implemented a version of a CFAR average in MATLAB but it's 'slow' and I need to speed it up. I included the pseudo code and logic below. I used a nested for loop to calculate the moving average but ...
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3 votes
1 answer
127 views

The power of signal processing when faced with hardware constraints

I am currently studying interferometry, but I have only just begun studying signal processing. I want to better understand the effect signal processing can have in maximising signal detection from ...
0 votes
0 answers
57 views

Is this a valid way to calculate SNR?

If I calculate 1.) the average power of a signal, $P_s$, in terms of the average energy of the signal, $E_s$ and take it as a constant over a given period of time, $T_s$, as $P_s=E_s/T_s$ where $E_s$ ...
1 vote
0 answers
72 views

Fisher Information Matrix for sinusoidal signal under multiplicative noise

Consider observations ($y$) of a sinusoidal wave with multiplicative noise ($v$) where we are estimating unknown frequency ($\omega$) and unknown initial phase ($\theta$). We can write this system ...
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0 votes
0 answers
55 views

Optimal Combination of received signals from two antenna

I really appreciate an answer or any hint how to approach this problem: Problem: A receiver has two antennas. The first antenna receives $Y_1=hx+n_1$, where $x\in\{-A,+A\}$, $h$ estimated channel, and ...
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0 votes
2 answers
71 views

Working out EIRP

There is a debate about the proper way of how to calculate the EIRP, so I need your help on which method is wrong and why please! Let's suppose we have the following: Output power: 165 W Reflected ...

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