All Questions

0
votes
0answers
39 views

processing a very noisy signal

I work on an ECG signal that I collect from a sensor, and it is very noisy. Having researched it above I read that FFT or so Nyquist-Shawon's casting theories were advised, being novice in the field ...
4
votes
2answers
158 views

Removing step-function like noise from signal, knowing when the step functions occur

So I currently have a system which is fit for very short time measurements. Whenever a measurement is long, however, there is a need to continuously update the reference, which, each time, will ...
3
votes
3answers
82 views

How Much Zero Padding Do We Need to Perform Filtering in the Fourier Domain?

Consider an $M\times N$ image $f$ and an $G \times K$ filter $h$. Given that convolution in the spatial domain corresponds to multiplication in the Fourier domain, then we can perform a convolution of ...
1
vote
1answer
27 views

Similarity in signal plots but dissimilarity in sensed content

I have two audio signals that look incredibly similar when plotted. However, when I play them, they sound quite different. The only difference I can even see in their plots is that one signal looks ...
0
votes
0answers
18 views

How To Find Frequency Range For Each MFCC Bin?

If I have 13 mfccs using 512 for fft size and 44100 for sampling rate, how can I find out which frequency range each mfcc bin represents? Do I need more information in order to calculate that?
2
votes
1answer
74 views

Hanning and Hamming Window

I am new in the field of signal processing. What's the different between Hamming and Hanning window? When we use the former and latter?
2
votes
1answer
79 views

Purpose of multiplying fft output by Hann window?

I'm working with some acoustic propagation models at the moment. A feature I've noticed in 2 of these models is that the output of the model is often multiplied by a Hann window in the frequency ...
1
vote
1answer
37 views

Graphical DT Convolution

Attached is the question 1 part B, solution and my attempt. My attempt seems to be not correct. can someone comment?
1
vote
1answer
44 views

Mel Cepstral Distortion

I am working on a speech synthesis model and I am looking to evaluate my synthesized speech. I found that most people use the Mel Cepstral Distortion (MCD) which can be calculated by the formula: $$\...
1
vote
1answer
32 views

Applying duality property to fourier transform of unit step function

For Continuous time aperiodic signals, the duality property of Continuous Time Fourier Transform (CTFT) is following $$\mathscr{F}\Big\{x(t)\Big\} = X(f), \qquad\text{then} \quad \mathscr{F}\Big\{X(t)...
0
votes
0answers
12 views

Can anyone please describe the relation between linear convolution and circular convolution? [duplicate]

It would be great if anyone could help. I am not able to find any relation amongst them, to me they are different things altogether.
0
votes
0answers
22 views

Should I increase the mean or the variance of Gaussian noise?

I am new in DSP. I am currently working with a project and I want to try which algorithm works better given different image noises. To test it out, I have been using the Gaussian noise in images. ...
0
votes
0answers
40 views

What is the error rate in compressed sensing?

Let $x \in \mathbb{R}^n$ be a $k$-sparse vector. Given $A \in \mathbb{R}^{m \times n}$, we have a measurement vector $y$ given by $$y=Ax$$ Let $\hat{x}$ be defined as follows $$\hat{x}:=\arg\min_{z\...
-1
votes
1answer
40 views

Why apply filterbank in power sepstrum not log power spectrum for cepstral coefficients feature(MFCC, IMFCC, LFCC) [duplicate]

In the original method for MFCC and any other method based on cepstral coefficients The original step is like this: |FFT|^2 -> Filterbank -> Log -> DCT but why not like that: |FFT|^2 -> Log -> ...
1
vote
1answer
32 views

What are the parameters of a calibrated spherical camera?

I'm aware if we have a pinhole camera model several parameters describe the specific camera (such as aspect-ratio, focal length, principal point, distortion parameters etc). There're standard ...
2
votes
1answer
64 views

Nyquist Plot for transfer functions with poles at the origin

I'm learning Nyquist plots and something has been seriously bugging me when treating poles or zeros in the origin. Nyquist plots obtains information based on the argument principle which states "If f(...
1
vote
1answer
107 views

Autocorrelation of sinc function

I'm having trouble on computing the autocorrelation of the sinc function I want to compute $$R_{hh}(\tau)=\int_{-\infty}^{\infty}\operatorname{sinc}(t) \ \operatorname{sinc}(t-\tau) \ \mathrm{d}t$$ ...
1
vote
0answers
29 views

Equivalence of the Power Spectral Density definitions

I am trying to show the equivalence of the following Power Spectral Density definitions in Matlab: Definition 1: $$ P(\omega) = \sum_{k=-\infty}^{\infty} r(k)e^{-j\omega k} $$ Definition 2: $$ P(\...
0
votes
2answers
35 views

Partial Fractions

Attached is image with solution and my attempt. I am trying to calculate the coefficients for partial fractions expansion of the following: $$ H(e^{j\omega}) = \frac{ \frac{1}{3} e^{-j2\omega} }{(1-\...
0
votes
1answer
27 views

Region of Convergence

In attached image why does the ROC have these values for $$ X(z) = \frac{1}{1-\frac{1}{3}z^{-1}} - \frac{1}{1-2z^{-1}} ~~~~~,~~~~~ 1/3 < |z| < 2 $$ and for $$ Y(z) = \frac{5}{1-\frac{1}{3}z^...
1
vote
1answer
27 views

Zero padding and 2D Fourier transforms: how does zero-padding affect phase?

It's pretty clear that zero-padding an image before performing Fourier transform simply enlarges the magnitude image (stretching it to the new, padded size). What I can't understand is how it affects ...
1
vote
2answers
44 views

Understanding of Histogram-of-Oriented-Gradients

I am learning about HOG and I understand it from here. A well-explained page with an example. I am not understanding this concept that how it works A 16×16 block has 4 histograms which can be ...
0
votes
1answer
45 views

low pass filter

I am new to DSP, I'm trying to implement a low pass filter in a microcontroller and I'm looking for examples on the internet. One of the simplest low pass filter (as its title says) is this. But I ...
0
votes
0answers
33 views

Is there a window with both a lower side lobe level and higher side lobe roll of rate than Blackman

Is there a window with both a lower side lobe level and higher side lobe roll of rate than the Blackman window - even if it is poor or useless for some other reason?
0
votes
0answers
35 views

Drawbacks of kalman filter

What are the drawbacks of kalman for attitude angels estimation...or what are advantages of mahony filter over kalman filter for attitude angels estimation?
2
votes
2answers
77 views

Doppler Shifting A Chirp Signal

So I have a digital linear chirp signal: $$ x[n] = \sqrt{\frac{2}{N}} \cdot \cos\Big( 2 \pi \frac{f_{0}}{f_{s}}n + \pi \frac{B}{N} n^{2}\Big) $$ Where $f_{0}$ is the initial frequency, $f_{s}$ is ...
1
vote
0answers
13 views

Is there any way to do 3D (Voxel Data) feature detection?

In the 2D image processing, there are ways to find and match features of the image (like corner of the edges). However, I could not find the equivalent of that in the 3D-voxel data (Here voxel means a ...
2
votes
1answer
32 views

Why do AAC files seem to have an inexact bitrate?

I'm using ffmpeg to encode audio files as AAC at 256kbps. However, the actual bitrate of the resulting file is rarely 256. It's usually a number close to 256 like 241, 255, 257, 254. In one case it ...
1
vote
1answer
57 views

Split audio file into audio phrases

I have couple of audio recordings of length 5 -7 min. I also have corresponding text to each audio file. I am not subject matter expert on speech to text but I am vaguely aware that much smaller ...
2
votes
0answers
16 views

How to calculate Walsh hadamard transform for image patches of odd sizes?

I was reading this paper on optical flow, which as apart of the algorithm makes use Walsh-Hadamard transform on image patches of size 2r+1. So far, where ever I have looked, I could only find that ...
0
votes
0answers
28 views

is this system invertible?

Is this system invertible? $$H \lbrace x(t) \rbrace = x(e^t) $$ I can find the reverse mapping from exp, but I'm not sure whether in systems theory this is considered reversible. I'd love to get an ...
1
vote
2answers
36 views

Physical meaning of average values of random signals

This question might be a bit stupid, anyway, i'll risk it, since i want to get better understanding of this subject. Let's consider random signal x(t), and let's say that we know that it is ergodic ...
0
votes
0answers
16 views

What is meant by peak value of gradient magnitude?

I am trying to write MATLAB code for the research paper entitled Echocardiography Image Enhancement Using Adaptive Fractional Order Derivatives. The two thresholds are given by a=(peak+min(Gmag))/2 ...
0
votes
1answer
29 views

Alternate Octave Commands for Matlab

can you tell me how to write video data to file.. what is the alternate of these 4 commands in octave ...
0
votes
0answers
8 views

guard interval calculation for multi-cell massive MIMO

I am interested in a multi-call massive-MIMO system modeled as in the works of T. Marzetta, for example: "Inter-Cell Interference in Noncooperative TDD Large Scale Antenna Systems". In these works, ...
2
votes
1answer
54 views

Phase of a real number

Could someone please explain in what case the phase of a real number is equal to -pi (and not pi)? I know that for positive numbers, the phase is zero. For zero, we define the phase as zero as well. ...
2
votes
3answers
56 views

“Dirac Comb” vs “Ones Comb”

While learning sampling theory - I noticed that examples of continuous signal sampling always achieved the goal via multiplying the signal with a "Dirac Comb". I was intrigued by the requirement to ...
1
vote
1answer
66 views

FFT Heart Rate Monitor on Arduino

Part of my project is to build heart rate monitor from Nano and a PulseSensor. I am having trouble working with the Fast Fourier Transform part of the code. This code here is from a library (...
0
votes
0answers
36 views

Detecting similar behaviour in audio files

Can anyone help, I'm trying to find a solution that would allow me the ability to look at a batch of .WAV files and detect ones which share a similar behaviour in the recording like the image attached....
2
votes
1answer
19 views

Beamforming back lobes question

When performing a conventional digital beamforming I see in some textbooks they show beam patterns as where the arrival angle ranges between -90 to 90 degrees. But then other places show the full ...
0
votes
1answer
38 views

DFT of 2d real signal and Hermitian symmetry

Knowing that DFT of n-values real signal in 1d consists of n/2+1 different values where the second half of the spectrum is complex conjugate of the first one (Hermitian symmetry). However in the ...
0
votes
0answers
20 views

What is the difference between a range filter and a low-pass filter?

A low-pass filter attenuates the high frequencies, preserving only smooth variations in the provided image. The result of an image which is low-pass filtered is an image with blurred edges (hence ...
3
votes
0answers
52 views

GNU Radio | Transceiver loopback adapted | Transmission stops unexpectedly

(This is a follow up question to a previous question: link) I have implemented a flowgraph of a transceiver loopback inspired by the examples found at ...
0
votes
0answers
13 views

Determining type of analog filter given its pole zero plot

How can i classify an analog filter given its pole zero map. For example: I've got my zero's located at $±2j$ and my poles located at $-1$ & $-2$ , then what is the nature of the filter? $ i.e, ...
7
votes
1answer
193 views

Optimal amplitude of an $m$-bit sinusoid

A continuous-time sinusoid of zero-to-peak real amplitude $A \le 2^{m-1}-0.5$ (e.g., for $m=16$, $A \le 32767.5$) is quantized to $m$-bit resolution by rounding it to the nearest integer (Fig. 1). ...
1
vote
0answers
20 views

What is the minimum and maximum cutoff frequencies for the antialiasing filter for this ADC?

https://www.analog.com/en/products/ad9675.html https://www.analog.com/media/en/technical-documentation/data-sheets/AD9675.pdf It says in the data sheet that the Anti-Aliasing Filter has : "...
1
vote
2answers
24 views

MATLAB - How do I get the Filter Function to get the output Energy Spectrum?

The image was from a question I posted on reddit, so ignore the title. I'm trying to write a program that plots these graphs I know that the first plot is just a plot of the source-signal so the "...
1
vote
0answers
16 views

Bandpass filtering with passband changing with time

Is it possible to implement some sort of filter which adapts as a function of time? Specifically, say I have a "noiseless" model of some signal which has the same frequency components at the same ...
1
vote
0answers
10 views

For non-uniformly sampled data, how to decide whether interpolation or Lomb-Scargle periodogram is better?

When handling non-uniformly sampled data, we can use one of the following methods to estimate the frequency spectrum: Interpolation in time/space domain, then go for classical periodogram OR Use Lomb-...
0
votes
0answers
15 views

What is the relation between smoothing and blurring?

Is there any difference between smoothing and blurring? Are these two operations the same or do these terms refer to different operations?

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