# Questions tagged [signal-detection]

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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 ...
1 vote
55 views

1 vote
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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 ...
15 views

### 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 ...
116 views

### 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 ...
50 views

### 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 ...
44 views

### 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 ...
135 views

### 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 ...
110 views

### 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/...
251 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,...
54 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 ...
245 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 ...
321 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? ...
802 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 ...
135 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 ...
264 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
35 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 ...
961 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 ...
104 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
34 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 ...
335 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 ...
49 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 ...
22 views

### 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) ...
57 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 ...
53 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 ...
1k 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 ...
833 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. ...
223 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 ...
45 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 ...
115 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 ...
928 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 ...
44 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. ...
27 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 ...