All Questions

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0answers
8 views

Intercepting a Bluetooth Signal

Hello fellow Stack exchange doods. I am but a humble teen who is currently suffering cause at lunch these "gangsters" blast their rap music really loudly in the cafeteria and I get mucho annoyed. So ...
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0answers
5 views

Spectrogram power/magnitude normalization in analogy with image intensity normalization

In analogy with the 8-bit grayscale image color depth, in which the intensity of a sample pixel is normalized to a value between 0 and 255 by taking into account the minimum and maximum intensities ...
1
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1answer
27 views

Question About Sampling White Noise

Assuming that we have a continuous signal $v(t)$ $$v(t) = \int_0^t g(u)\, \mathrm du\tag1$$ where $g(t)$ is white noise.Then take the derivative of it. $$\frac{\mathrm d}{\,\mathrm dt} v(t) = g(t)\...
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0answers
15 views

Is tanx(t) stable?

I am highly confused about the stability of tanx(t). If we provide a bounded input such as x[t]=u[t], the output is bounded I have confusion about stable Is the function BIBO stable and also is it ...
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0answers
13 views

confused in using modulation technique

I am given a question in which I have to draw the spectrum of the signal $m(t)$ and then draw the spectrum of this modulated signal. The signal is $$m(t)=\cos(1000\pi t)$$ Now in solution manual ...
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0answers
7 views

How do I interpret the Wavelet scattering transform frequency plane and tree diagrams?

I've been reading through this paper on "Invariant Scattering Convolution Networks" and am having a difficult time interpreting the tree diagrams and frequency plane diagrams shown respectively below. ...
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2answers
20 views

What is the interpretation of Fourier Transform containing only imaginary part?

The FT of a unit step function is taken as: $$ X(\omega) = \int_0^\infty e^{-j\omega t}dt = \frac{-1}{jw}e^{-j\omega t} \Biggr |_{0}^{\infty} = \frac{j}{\omega} $$ The transform only has the ...
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0answers
13 views

How to save a specific frequency range as a wave file?

When I use the bandpass filter on an audio file to retain, say, all frequencies between 1300-1400 Hz only, I end up with an audio spectrogram showing this bit and all the rest as black. Exactly as I ...
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1answer
20 views

Why is the ROC of Laplace transform independent of imaginary part of s?

An integral is defined as converging if it yields a finite value upon application of limits of integration. It is divergent otherwise. Now sticking to the mathematical notation of Laplace transform, ...
0
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1answer
20 views

What is the name of this filter?

I am having this simple function which acts on two state variable $s_t$ (states being $\{0,1\}$, boolean in sense), and I am evaluating it in discrete time steps. The function is $f_t=1$ if $s_t$ has ...
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0answers
9 views

Symmetric Capacity of a Binary Discrete Memoryless Channel

While reading this paper https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5075875, I found that the the symmetric capacity of BDMC $W$ is given by $$I(W) = \sum_{y\in Y}\sum_{x\in X}\...
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0answers
13 views

How to find the filter coefficient of matched filter to detect the pulse of a signal?

I would to understand how to find the coefficient of a matched filter. Let's consider we have a signal and the signal is buried in the following noise. we want to find the coefficient of a matched ...
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0answers
14 views

Calculating N for DFT

We want to compute an N-point DFT of a one-second duration compact disc (CD) audio signal x[n], whose sample rate is $f_s = 44.1Khz$ with a DFT sampling of 1 Hz. (a) What is the number of necessary x[...
0
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0answers
27 views

PLL carrier recovery: intermediate versus baseband

When looking at carrier recovery, a PLL is often applied to correct the frequency offset between the local oscillator and the transmitter after down conversion. I'm wondering what happens to the PLL ...
0
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0answers
6 views

How to match resolution of two or more signals

I have received the following 4 time-series signals and wanted to do some data analytics using these. Although the sampling is the same for all of these signals, 2 samples per second, problem is that ...
0
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0answers
7 views

Calculating noise floor of digitization system using FFT

I am trying to calculate self noise of a digitization system with differential inputs.For this purpose, i select a differential channel, set input range to +/-5 V, short both differential inputs and ...
2
votes
2answers
147 views

Do Fourier frequencies actually exist in real life in form of “instantaneous frequency”?

For me, this is a very awkward question to be asked, as at this point in my studies I'm supposed to be quite expert with elementary mathematical tools like Fourier transforms, but this has always ...
0
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1answer
9 views

MATLAB & Power Spectral Density - Error - Getting the same range of values regardless of sound type?

I wrote code [attached at end of question] to take .wav files of child vocalizations and tried to see if there are valid ranges for the formants F1:F2:F3 for the 5 ...
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0answers
12 views

Mscohere in Matlab-why would the coherence tends to 1 as nfft increases?

Does anyone have a clue as to why -using mscohere- the coherence becomes exactly one for all frequencies if nfft is set to about 190-200. I know it's standard practice to set it to a number that is a ...
0
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1answer
30 views

rate 1/128 channel code for 5 bits of information

I need to construct channel code for 5 bits of information for a wireless channel. Possible code rate could be as low as 1/128 (very reliable). At decoder I assume to use channel LLRs as decoder input ...
0
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0answers
12 views

Getting SNR of reconstructed signal in MATLAB

I am trying to run code to compare the efficiency of various basic sampling methods such as ideal sampling, natural sampling and so on. I want to then use average power to see how accurate the ...
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3answers
67 views

What is the precise definition of a nonlinear signal?

I tried to find the the precise definition of a nonlinear signal. However it is not easy. How can we define a nonlinear signal?
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0answers
16 views

Tetrahedral microphone array beamforming in MATLAB

I have a microphone array of 4 channels taken as channels [6,10,22,26] from Eigenmike spherical microphone array. I wish to do 3D beamforming and create $8\times 4$ beams, 4-elevations with 8 ...
2
votes
1answer
29 views

Odd-order Butterworth filter gain at cutoff frequency

Wikipedia gives the gain of an n-order Butterworth filter as $$G^2(\omega)=\left |H(j\omega)\right|^2 = \frac {{G_0}^2}{1+\left(\frac{j\omega}{\omega_c}\right)^{2n}}$$ here. If you look at the gain ...
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0answers
17 views

IFFT, negative frequencies and noncausal impulse

When using the IFFT to compute an approximation to the IDTFT, frequency range is 0 to 2$\pi$ versus $-\pi$ to $\pi$. This produces a different impulse sequence(causal I think). How do you calculate ...
0
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1answer
10 views

Fourier Transform of the Hilbert Transform of cos(t) (using Fourier time-shifting property)

If $x(t)=cos(t)=\frac{1}{2}e^{jt}+\frac{1}{2}e^{-jt}$, then $X(\omega)=\pi \delta(\omega-1)+\pi \delta(\omega+1)$. If $y(t)=cos(t-\frac{\pi}{2})=\frac{1}{2}e^{j(t-\frac{\pi}{2})}+\frac{1}{2}e^{-j(t-\...
1
vote
0answers
10 views

Understanding performance of Lucas Kanade Iterative Image Registration Technique

I am reading the paper: Lucas, B. D., & Kanade, T. (1981). An iterative image registration technique with an application to stereo vision. I am having some trouble understanding section 4.3 ...
0
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2answers
24 views

Does a phase rotation introduce a delay?

Suppose I have 2 complex time series, $x_1$ and $x_2$. If I measure the delay between $x_1$ and $x_2$, I get $t$. If I make $x_2 = x_2 e^{-j 2 \pi 10}$, and measure the delay between $x_1$ and $x_2$...
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0answers
6 views

Looking to simulate sound level meter (read microphone audio signal into 1/3 octave)

I am looking to pull audio from a microphone and analyse the 1/3 octave data. Can anyone suggest a software library to do this that I could then build a software interface on top of? Initially looking ...
0
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1answer
9 views

Comparisons of FIR Causal filters of type HRIR in Discrete Time and Frequency Domains

I have just implemented a Discrete Time Convolution between HRIR filter at a range of angles. I also implemented an Overlalp-and-Add method and FFT and IFFT to compute the same convolution in ...
1
vote
1answer
20 views

How to achieve a smoothed frequency phase response with no outliers

I have two sampled signals, which I then perform wavelet analysis on, by synthesising the Filterbank, perform the dft on each kernel, and the dft on the sampled signals, and multiply together. ...
0
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1answer
14 views

Correlation of vector signal

This is probably more of a mathematical question than a signal processing exclusive, but I hope somebody here knows an answer! I want to compute the autocorrelation of a signal, which is a vector (so ...
0
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0answers
11 views

Determining timing error for sampling

I am writing a small program for sampling a series of sensors on an Arduino. The sampling process is not 100% perfect, depending on how many sensors I am reading, the actual difference between two ...
0
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1answer
26 views

How Could I extract the signal in the below Image

This is my first post so sorry if I make any mistake. The entire signal length in the screen shot below is 10 second. I ran a first order low pass filter (digital) at 10Hz cut-off frequency, and I ...
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1answer
22 views
1
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2answers
41 views

Detecting a three-tone signal in real-time

I'm new to digital signal processing, and I've been looking into FFT, filtering, Matlab etc. What I'd like is to build a program which will detect when a certain BEEP is transmitted through a trunked ...
2
votes
0answers
27 views

Is it possible to approximate certain skewness and kurtosis values using an IFFT?

I have time domain data for a signal that behaves randomly but has non-random (non-Gaussian?) skewness and kurtosis values of ~0.9 and ~7.4, respectively. The FFT of the signal shows that it's not ...
0
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0answers
30 views

Z domain transfer function to difference equation

I want to convert this transfer function: $$\ \frac{2\cdot(z-0.5)\cdot(z-0.6)}{z-1}$$ to a difference equation, but I have no idea how. Can someone help me? Thanks, Arjon
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0answers
10 views

Automatically crop out certain region around red objects

I have the image seen below and I would like be able to automatically crop out everything around each red section - not enough to overlap but enough that you can see how connected to the green parts ...
1
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1answer
58 views

Maximum likelihood estimation complexity computation

I have a basic question about maximum likelihood (ML) estimator and its implementation. I am trying to simulate a communication system, while using ML at the receiver side to find the transmit ...
-1
votes
0answers
19 views

DSSS — Why does bandwidth increase when modulating with a chipping sequence?

Here is an example image: Why does the bandwidth increase when modulating the carrier with a chipping sequence. All it's doing is phase shifting the carrier sinusoid with -1 and 1 more frequently. ...
0
votes
1answer
16 views

Equivalence of difference equation with system of difference equations

I have this system and tried to write down its difference equation as follows $$ y[n] = b_0v[n] + b_1v[n-1]\\ v[n] = x[n] - a_1v[n-1] $$ I was asked to prove that the system can be ...
0
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2answers
25 views

Confused in difference between sequence versus signal?

I am learning basics of signals and systems with MATLAB If i create a vector in matlab such that x=[ 2 5 10 20], will it be considered a sequence or a signal? As ...
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0answers
11 views

SLAM from partly occluded LiDAR sensor

I am building my first project which will use 2D LIDAR for SLAM and the robotic platform is a small car. However the LIDAR is hidden inside and it's occluded by 4 cylinders which connect the roof with ...
0
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1answer
19 views

Matlab: Different 1-D FFT results with and without zero-padded

Recently I am implementing FFT with C code. So I use Matlab for algorithm verification. As Radix-2 FFT was chosen, I've learned that zero-padding technique could help to reach 2^N limitation without ...
0
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1answer
28 views

How can I specify the distance between values in such row

I have a question, about verifying the value which are near to each other in such row, Is there any algorithm which can determine that ? Suppose I have a vector $z_i =$ {$z_1 , z_2, z_3, . . . ., ...
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0answers
28 views

Taking FFT of a signal with lots of “holes”

I have a time series that is spotty (more 'no sample' than 'sample' at each second, which is the sample rate). There are obvious trends when viewed visually. However since there are holes, the FFT ...
0
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1answer
22 views

Overshoot when using Bessel filter

Here is simple code to illustrate overshoot using bessel filter: ...
0
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1answer
18 views

Synchronization Accuracy Required For Communications

One of the biggest problems in phase modulated communication is discovering when your signal has arrived. High accuracy in this area is important, as even a quarter wavelength error can cause the ...

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