Questions tagged [signal-detection]

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2answers
793 views

How to calculate the phase shift AND time delay of non-periodic signals

Say I have two non-periodic signals, $f_1(t)$ and $f_2(t)$, with Fourier transforms $F_1(\omega)$ and $F_2(\omega)$. Basically, I need to line up $f_1(t)$ and $f_2(t)$ as close as possible, and I am ...
4
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0answers
93 views

Finding the parameters and endpoints of a sinusoid

Suppose I have some signal $$ s(t) = n(t) + \left\{\begin{aligned} &0 &&: t < t_0\\ &A e^{i (2 \pi f t + \theta_0)} &&: t_0 \le t \le t_1\\ &0 &&: t > t_1 \...
3
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0answers
25 views

Inconsistant Variation in BLE Beacon RSSI Values for Distance Measurement

I am developing an application to estimate the distance to a BLE Beacon using its RSSi values measured from a Mobile Phone. But when I started to collect data I could see that they varied so much that ...
3
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0answers
136 views

Multilateration of Sound in 3D Space

TL:DR - How can you find the 3D coordinates of a emitter than transmits an impulse signal? STORY: I'm working on something to improve my bird-watching. I've got a camera that can take pictures of ...
3
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0answers
89 views

Energy Detection in Presence of Colored Gaussian Noise

Before asking my question, let me introduce the context: For spectrum sensing based on energy detection, which has been widely studied in presence of AWGN, the optimal detection threshold is computed ...
3
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0answers
611 views

Incorrect Frequency results when using Multiple Signal Classification (MUSIC)

I am using MUSIC (Multiple Signal Classification) to determine Direction Of Arrival (DOA) and frequency of signals impinging on an Antenna Array. I am using a function ...
3
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0answers
232 views

Segment/Idenfication of signal from a spectrogram

I have the following Spectrogram of a signal: Essentially, in this signal, I know there is one point of interest (between 60-80) and between the the particular frequencies. I could, potentially ...
3
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0answers
57 views

Intuition of Location on the Conic Axis TDOA solution

In an old paper "A New Approach to Geometry of Range Difference Location", there is a mathematical derivation that does not include any mention of the relationship to the underlying problem. In the ...
3
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0answers
794 views

calculate root mean square, ratio of power, constant false alarm, … of a signal

I am new to Digital Signal Processing, and am reading a paper. I don't know how they can extract some features from signal, like root mean square (RMS), Constant False Alarm Rate - CFAR, Mean Value ...
2
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0answers
32 views

How to remove varying noise from strain data in MATLAB

I'm very new to signal processing. I have some data measured over time at 800 Hz. I'm interested in the high frequency signals. You can easily identify them in the image below (in this case, 3 signals)...
2
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0answers
60 views

ESPRIT signal subspace and rotational invariance

so in ESPRIT[1,2] we have some signal of the form: $$y[n] = \sum_{k=1}^{K} a_i(k) e^{j\omega_k n} + N[n]$$ where N is noise, then we get the autocovariance matrix $$R_{yy}=E[y[n]y[n]^*]$$ take the ...
2
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1answer
46 views

BER performance of fractional equalizers for colored noise

I am trying to compare the BER performance of fractional and symbol spaced equalizers for channel equalization in colored noise scenario. I have found from simulation that for positively correlated ...
2
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0answers
56 views

Is there in signal processing similar method than Otsu's method in image processing?

I'm just wondering that is there any similar method for separate signal and signal+noise in signal processing like otsu's method set threshold to valley of image histogram? And if there is how can I ...
2
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0answers
493 views

Peak detection techniques

I'm using a cell-averaging constant false-alarm rate (CA-CFAR) detector to detect peaks like the first one in the following plot: The magenta line is the adaptive threshold, which is the local ...
2
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0answers
52 views

Supervised instrument recognition

Is it possible to use NMF for a sort of supervised polyphonic instrument recognition? I have training data for a timpani and training data for a bongo (or a bongo, snare and box drum). How can I ...
2
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0answers
44 views

Signal conjugation detected on RF recording samples, why?

I collected spread spectrum signals at 400 MHz at low elevation angles using Software Defined Radio complex sampling over the seasons. I noticed that over watery, icy surfaces, the RF samples are ...
2
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0answers
107 views

Is there a way to apply blind source separation using ONE mixture?

This question is a follow-up for my previous one: Reduce the "glare" effect of a receiver within a system. I have broken the problem into pieces and I humbly think that I've got a way to ...
2
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2answers
111 views

Signals - question due to sampling

I don't have an idea how to start it. Help pls :) $$m = z(t) + \frac{\operatorname{Sa}(t-T)}{4}$$ We have some signal $z(t)=\left(\operatorname{Sa}(\frac{t}{T})\right)^2$. How often the m signal ...
1
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0answers
38 views

MFCC parameters for gunshot recognition

I'm writing a gunshot detector software. I'm using this article as reference:https://arxiv.org/ftp/arxiv/papers/1706/1706.08759.pdf. For now, my software is able to recognize an impulsive sound. Now, ...
1
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0answers
56 views

Extracting signal from data using Otsu thresholding in MATLAB?

I am very new to signal processing. I am trying to extract a signal from my data using otsu threholding but it's not fully accurate. In this case I know that there is going to be a single signal in ...
1
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0answers
79 views

Is there a situation when maximizing SNR doesn't also maximize probability of detection?

The problem I'm working on is signal detection of a radar signal, but I suspect this problem shows up in many different branches of signal processing. Background: From [1], the factor $I_f$, by ...
1
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0answers
42 views

Required number of measrments for signal recovery in a compressed sensing MMV problem?

For multiple measurement vector (MMV) problem $Y=AX$ where $A$ is $m \times n$ sensing matrix and $X$ is $n \times L$ matrix haveing K non zero rows. What are the necessary conditions on the ...
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0answers
67 views

Sufficient conditions for exact signal recovery using OMP?

For a compressive sensing model : $$y_{_{MXN}}=A_{_{MXN}}x_{_{NX1}}$$ where $x$ is $K$ sparse, what is the sufficient condition for Orthogonal matching Pursuit (OMP) to exactly recover the data for ...
1
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0answers
46 views

Source localization in 3d

Let's say I have a 4-sensor square-shaped array in 3d space, with sensors at $$ s_1 = [1 \ 0 \ 1] \\ s_2 = [2 \ 0 \ 1] \\ s_3 = [1 \ 0 \ 2] \\ s_4 = [2 \ 0 \ 2] \\ $$ And a single source somewhere ...
1
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0answers
429 views

How to detect overall error between two signals and also track changes occurred

I need to develop an algorithm that will compare two signals (1 Reference Signal and other is measured signal values from sensor) and generate some metric(s) to describe changes between them. I am not ...
1
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0answers
116 views

Best Method to Separate square wave and smooth wave

I have a signal consists of a smooth wave and square waves. Is there comprehensive method can separate square wave and smooth signal? I looked for the likelihood ratio test but cannot find any ...
1
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0answers
23 views

Classification test by embedding true positives in high frequency recordings

I'm evaluating a cyclostationary approach to signal classification. My first step in doing so was generating signals and embedding them into a few specified parameter sets of the Watterson channel ...
1
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0answers
746 views

Detecting delay and sample drift in audio files (wav, mp3, etc.)

In my application, I have an audio recording with background music. I know which song is playing in the background and have a copy of the original song (wav, mp3, etc.). The goal is to align the ...
1
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0answers
45 views

How does the error in azimuth angle vary as one moves away from the boresight direction of a radar

My question is basically same as the title. I am trying to find a mathematical model which provides the error, $d\theta$, in azimuth angle($\theta$) as one moves away from the boresight direction of ...
1
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0answers
92 views

Received signal envelope PDF to power PDF [Wireless Communications]

I am deriving the probability density function (pdf) of the received wireless signal envelope in multi-path fading channels. I wish to transform this envelop PDF to the power PDF of that signal. I ...
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0answers
226 views

Can we use SVD to solve single channel deconvolution problem?

I have seen using singular value decomposition (SVD) to solve deconvolution problem for example truncated SVD (TSVD) . It appears there is also a connection between Tikhonov regularization and SVD. My ...
1
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1answer
131 views

Detecting expected patterns in repeated measurements

I am new to signal processing and I am trying to learn myself. To understand what i am interested in, let me show this on example (note that this is just a random example to illustrate). Here is some ...
1
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0answers
304 views

Event detection in a running person's acceleration data

I am trying to detect some events on this signal : This is the acceleration of someone running. By eyes we can detect many blocs, sometimes separated by a little interval. I would like to be able to ...
1
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0answers
364 views

Audio - TDOA and $\tt xcorr$, find the 'best' peak

I try to locate a mobile device using multilateration. The mobile device acts as the receiver and in the room I have three speakers. To calculate the position I need the time difference of arrival (...
1
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0answers
106 views

Detecting special points in signal

What tool/filter/mathematic operation would you use to detect the red points marked in this signal? As you can see there are several differentiated groups and I want to detect those moments in which ...
1
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0answers
402 views

What is the best algorithm to detect leading edge?

I am interested to detect leading edge of one dimensional signal. There may be several algorithm for edge detection, specially for image processing (2 dimensional), but my interest is on one ...
1
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0answers
64 views

General question on signal processing guidelines for emergency shutdown applications (i.e. medical devices)

Disclaimer This might be a very broad question. I ask it out of curiosity, because the topic came up in a discussion lately. Hence, I do not have any specific applications or even data that I could ...
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0answers
45 views

How do I correctly receive a signal using a signal analyzer?

For the past few weeks, I have been trying to send a Zaddof Chu signal using a vector signal generator, and receive it using a signal analyzer. Both devices are made by R&S. However, the signal ...
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0answers
75 views

Heterodyne detection

Prove that with appropriate choices of the phase $\varphi$, one can recover the quadratures of $m(t).$ Attempt The context of this question is weak optical signals combined with a strong local ...
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0answers
84 views

processing photo diode array data

We have designed a system which has an 8X8 array of photo diodes, we sense 10ns pulses of laser falling on those photo diodes with a repetetion rate of maximum 50Khz i.e. 20us, we were successfully ...
1
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0answers
90 views

Application of BIC, MDL, AIC

I understand that mathematical motivation behind Bayesian Information Criterion (BIC), Minimum description length (MDL), Akaike information criterion (AIC) are different but I am assuming that there ...
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0answers
38 views

Variation in Signal Power in Mimo system

I am exploring methods for reducing computations required by MUSIC (Multiple Signal Classification) Algorithm. Most of the computational power is spent on calculating SVD. My approach is to take ...
1
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0answers
58 views

determining walsh function components of signal after passing through non linear process

When a sum of sine waves is passed through a non linear process, harmonics and intermodulation distortion products are created, which are visible when applying an FFT to the signal. This causes ...
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0answers
275 views

Train Pulse Recognition in Medium Voltage Networks

I just started a project in the Smart Grids area. It involves the recognition and quick extinction of earth faults in a medium voltage system. The system works automatically and pretty much gets rid ...
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0answers
167 views

how to detect the center frequency of a QRS complex in an ECG signal?

i want to design a filter that can effectively detect the QRS complex in ECG signal(whose Fs=360Hz) and reduce high frequency noise components. i want to know as to how the center frequency is ...
0
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0answers
26 views

Obtain SIB1 messages from CPRI the captured DL IQ data

I am a beginner in the signal processing, and I know some python and I have a project I'm working on which is about Obtaining SIB1 messages from CPRI the captured DL IQ data. I have captured some DL ...
0
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0answers
26 views

Strange signals in wifi channel

I am currently working with a USRP B200 mini-i to receive 802.11 signals from various usb wifi devices. When sending packets with the USB device over a channel, lets say 2.412GHz, i can't really see ...
0
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1answer
36 views

Can an audio recording tell whether it is made in a large or small room?

The conversation of one or more people will be analyzed. I think need to look for something similar to reverberation or echo in an audio signal. How can this be implemented? Update: small room is ...
0
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1answer
31 views

Synchronize device to audio stream - Approach

I am working on a device which's actions should be synchronized to the audio played. The audio stream is known in beforehand and can be altered to contain signals for the synchronization. But the ...
0
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0answers
20 views

Understanding shift in Q values?

Can any one help me understand why there is a shift in Q values? It seems there is a DC offset/bias. How do I remove it or set it accordingly to make it equal to the I values/waveform? I am using a ...