# All Questions

16,634 questions
19 views

### How would i get the total variation demonising for an X-ray image

Total Variation for an X-ray image. using rof model Is there any function to find total variation. TV with respect to I by $$\sum\sqrt{i x^2+i y^2}+\lambda\|i-g\|$$ $I$ is the denoised Image $I x$ ...
82 views

### Why do waveforms that are symmetrical above and below their horizontal centerlines contain no even-numbered harmonics?

All About Circuits site states that waveforms that are symmetrical above and below their horizontal centerlines contain no even-numbered harmonics. Can somebody explain this mathematically, or point ...
13 views

### If we treat an image as matrix, are there interesting meaning/observation to the concepts/technique like det trace eigenvector/value [closed]

det,trace,eigenvector/value,LU,QR,SVD,etc.... For example, det may be somewhat preserved under rotation. And eigen decomposition can be used for image compression.
62 views

### The non-recursive filter [closed]

An FIR digital filter of length N with impulse response ${b(n)}, n=0,1,...,N$. Therefore, the complex-valued, multiplicative function $H(f)$ is the filter's frequency response.It is defined by a ...
33 views

### Equivalence of ML and FFT peak finding for Single-Tone estimation

My understanding is Maximum Likelihood and FFT peak finding for a single tone produce the same results assuming the ML is restricted to the same frequencies as the FFT. I was wondering if there was ...
10 views

### Why packet wavelet transform for frequency analysis gets non-informative results for some frequencies and phase?

I wrote the following code in Julia for packet wavelet transform. It uses Haar transform (I've chosen low-pass filter to keep average value of the signal). As usual, it works recursively filtering ...
76 views

### Algorithms for detecting the difference between two signals

If I have two signals $X$ and $Y$, where $X$ is a clean signal and $Y$ is the same signal with linear white Gaussian noise and an amplitudes of $10^{-4}$. How could one use an algorithm to detect if ...
34 views

### Dynamic compressor - ratio in logarithmic scale problem

I want to use decibels to describe compression ratio. So for example ratio 4:1 means that every 4 input decibels above threshold causes raise of output only 1 decibel. And I also want ratio to be ...
21 views

### Windowing in frequency domain. how to cut a spectrum using window function in frequency domain?

I have a set of measurement data of a FMCW radar and trying to estimate the system transfer function. In the frequency spectrum, I can see multiple peaks due to the non-linearity that exist in the ...
14 views

### Particular Correlation formula

I'm reading a book where the autocorrelation of white noise is expressed as: What is the term $Q(k)$ and why is is expressed as an average value of a dot product ?
87 views

### For complex values, why use complex conjugate in convolution?

Taken from Adaptive Filter Theory (2014) written by Haykin page 110 : $$y(n) = \sum_{k=0}^{\infty} w_k^*u(n-k), \quad n=0,1,2,...$$ where $u$ and $w$ are complex values. My question is why use ...
22 views

### Matlab spectral shift [closed]

I need a matlab codes to resolve this... This is using for a audio file. Download here. https://www.nasa.gov/specials/InSight-Sounds/06-MASTERRESAMPLED-48Kraw_velocity_0.6_normalisedx1.wav Matlab ...
120 views

### Can $\delta(t+\infty)$ be a legitimate signal?

Mathematically speaking, when I try to use some signal to disprove a system is invertible, can I use the signal like $\delta(t+\infty)$ ($\delta$ representing the Dirac distribution)? For example, the ...
10 views

### I need help calculating blind source separation metrics; namely - SDR, SIR and SAR using bss_eval toolboxes?

I am referencing this paper: https://hal.inria.fr/inria-00564760/document I am using this download link for the MATLAB files: http://bass-db.gforge.inria.fr/bss_eval/ (Version 2.1) Background Ok so I ...
20 views

### DCT Based modelling

I have been reading this paper on MRI and I only do have novice level signal processing insight. I could not understand the following model: The displacement field (i.e. d) is modelled as a linear ...
66 views

### Nyquist sampling

I know that if $f_\mathrm{m}$ is the "Nyquist frequency" (max frequency) and $f_\mathrm{s}$ sampling rate then $f_\mathrm{s}>2f_\mathrm{m}$. Am I correct so far? I have a signal $x(t)$ with max ...
53 views

### Do Nyquist samples have the same sum as the integral of the signal?

Assume I sample a signal according to the Nyquist criterion. Then I perform a simple summation / integral over a linearly interpolated signal. Is this equivalent to the integral over the continuous ...
18 views

### Do I need equally paced values to do a Fourier Cosine Transform?

I am gathering data from a sensor, but the data gathering depends on a code running, so the timing is not precise to make it equally paced. What I mean is this, the time it takes to do measurement #1 ...
45 views

### How the zero - phase filter without filtered signal truncation at the end can be implemented?

I mean what for the window FIR filter the filtered signal is truncated at the end because impulse response of the filter is symmetric. For example the code from here (in python) (lowpass FIR filter) ...
22 views

### Coherence and non-linear interactions

Reportedly, coherence-based metrics are primarily influenced by linearity in phase. However, Klein et al report that coherence is also: ... very sensitive to fluctuations of linearity in ...
25 views

### retrieving complete 2d autocorrelation function from 2d power spectral density function (numpy.fft.ifft2)

My question is at the boundary between signal processing and python. I have a 2d power spectral density function (PSDF) constructed on Nx/2 + 1 and ...
35 views

### Proof that first difference filter amplifies noise

I'm a bit befuddled by noise's effect on derivative filters. I've always 'known' that straightforward first difference derivative filters of discrete signals amplifies noise, but I'm struggling to ...
12 views

### matlab code for variable step size lms algorithm for adaptive fiktering [closed]

Actually i do not have much knowledge about digital Signal Processing , but i had selected variable step size least mean square algorithm for my project.So please can any one please provide me the ...
63 views

### Support of the convolution of two rectangular signals

I'm trying to convolve two rectangular signals in the frequency domain $$H_1(\omega) = u[\omega +.2\pi] - u[\omega -.2\pi]$$ and $$H_2(\omega) = u[\omega +.1\pi] - u[\omega -.1\pi]$$ My result is a ...
38 views

### May I know how to find Time frequency power spectrogram of a signal?

I am analyzing EEG signal and I am unable to understand the term Time-Frequency Power Spectrogram. Please Can anyone help me? Thank you in advance.
28 views

### Band Edge Filters

I am interested in using Band Edge Filters to do carrier frequency recovery but this is kind of secondary to my question which is: How do you build an FIR filter which isn't symmetric about the ...
33 views

### References ISAR - Inverse Synthetic Aperture Radar [closed]

Anybody know a reference to start understanding ISAR? Book or article. Thanks!
26 views

### What is wrong with my PSD computation?

I'm trying to calibrate the RX of my SDR Board to become a measuring receiver. I.e, by connecting it to a known source of power (in my case, a frequency generator), at a fixed frequency, I'm trying to ...
21 views

### Length for a spreading sequence [closed]

For the CDMA, we use different spreading sequences. Each sequence has a SF length. How to choose the SF length?
48 views

### What Is the Difference between Parseval's Theorem and Plancherel Theorem?

Wikipedia gives Parseval's theorem as follows. Parseval's Theorem , is the Fourier transform of x(t). And Plancheral's theorem is given as , where is the fourier analog. Plancheral ...
39 views

### What will the impulse response of a matched filter look like if the input is complex?

If $h(t)$ is the impulse response of a filter matched to a signal $s(t)$, I read that $h(t) = ks(t_o - t)$. But what if the signal is complex? I went through the derivation of the matched filter and ...
1k views

### Fourier transform of given signal

This is the signal whose FT i need to find, at first i thought that i could solve this as a convolution of two rectangular pulses, but i could not find pulses that fit into this (it turns out that ...
31 views

### Difference between autocorrelations

M. H. Hayes calls in his book "Statistical digital signal processing" autocorrelation sequences $r[k]$. For optimal filters the desired autocorrelation has the index d -> $r_d[k]$. However, often ...
23 views

### Preamble detection using cross-correlation

I am generating a preamble with a sequence of [1 -1 1 -1 1 -1....] and spread with a barker-11 sequence. Now, the transmitted signal becomes [B(Barker), -B(Inverse of Barker), B, -B,....]. In channel, ...
31 views

### sum for a chirp signal

I have a chirp signal. In Matlab, the command is $s=chirp(t,f0,t1,f1)$. I make the following sum with Matlab: $y=rand(1,size(s,2))+s;$ Here is my question: What is the theoritical equation for $y$? I ...
9 views

### How to implement freq convolution layer?

I am referring the paper https://pdfs.semanticscholar.org/31c7/4962122ba5fe1c469101b5bc2ae6d88c9c18.pdf. In the paper, for CLDNN network first layer is freq convolution. How to implement the same for ...
29 views

### Amount of exactly approximated samples with Padé approximation

I've already had some good discussion with Fat32 in this question yesterday. Today I'm confused again. The author of Statistical digital signal processing and modeling M.h. Hayes and Fat32 both ...
13 views

### What can used in user clustering to calculate the fitness using particle swarm optimization [closed]

Data clustering use centroids position of particles to calculate the fitness function using particle swarm optimization. Similarly for user clustering
19 views

### Language detection from audio

I'm trying to do a simple test on language detection on a video input. Basically, given a .mp4 file, I need to process the audio tracks (can have primary and ...
41 views

Given a signal $x[n] = [1, 2, 3, 4, 5]$. How many transfer functions can be found with Padé approximation which have a causal impulse response and start with those five samples. How many of them are ...
63 views

### Can a software defined radio with a frequency range of 300 MHz – 3.8 GHz detect AM (535 to 1705 KHz) and FM signals (88 to 108 MHz)?

I am interested in knowing whether BladeRF SDR with a frequency range of (300 MHz - 3.8 GHz) detect AM and FM frequencies? Also, how important is the sampling rate of the SDR. For example, BladeRF has ...
62 views

### Recover Audio from Spectrogram Image

I have applied transformation(Constant Q Transformation) to my audio time domain signal, this gives me Frequency vs Time representation. Now, the CQT values consists of complex values(84*260), but ...
37 views

### Potential issues arising from too stable discretization

When numerically simulating a system, usually some kind of discretization is necessary, obtained by some kind of z-transform, such as, for instance, the bilinear transform \$s\mapsto \frac{2}{\triangle ...
17 views

### What is the difference between using corrcoef to compare two signals by column, and as whole matrices?

I have two matrices, which represent acceleration readings of the same event from two seperate sensors, and I would like to calculate the correlation coefficients so that I may get a measure of how ...
11 views

### Restrict a state value in an Extended Kalman Filter

I am trying to use an EKF to filter/predict a noisy sinusoidal waveform using the states of phase, rate of change of phase and amplitude. I am finding, however, that sometimes the EKF amplitude state ...
10 views

### TiVa C series123g [closed]

I had recently purchased the Tiva C series eval board for a project. Is there a way to implement a filter and an amplifier on the board itself and not with the help of hardware components?
69 views

### Definition of DSP Terms

can someone define/explain briefly (or with some detail-> up to you) the following terms: Block Processing? and what are the differences between it and Sample Processing? (removed) What is a 3D ...
73 views

### How is frequency related to data rate?

How does (if it does) frequency affect/relates to Data Rate. Why for example using the same modulation, LoRa (in the physical layer), you get somewhere around 250kbps at 2.4Ghz and only 20kbps at ...
36 views

### FFT returns large low-frequency power - probably because signal is interpreted as containing cycles that do not fit. How is this called?

So I have a large number of signals like the one in the first picture below and I would like to extract and compare the frequencies within them. I applied a Fourier transform which resulted in ...
44 views

### What language or framework would you use to develop and test natively algorithms meant to be ported on an embedded hardware later?

I am trying to find a nice clean solution to this problem since some days now, and couldn't make myself to stick to a solution. I need to develop some stream and block processing for audio, including ...

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