Signal Processing Weekly Newsletter

Signal Processing newsletter

Top new questions this week:

How to improve an FFT AM demodulator for NOAA APT satellite imagery?

My question involves proper FFT Technique for AM demodulation, in the special case where the modulation rate exceeds the carrier frequency. This question has a specific hobbyist application, the ...

fft image demodulation  
asked by Paul 1 vote
answered by JRE 1 vote

Realization of IIR resonator

The measure of a given frequency $\omega$ in a signal $x(t)$ is: $\frac{1}{N}\sum\limits^N_{t=0}x\left(t\right)e^{^{-i \omega t}}$ This is basically an average of the correlation between the signal ...

fourier-transform infinite-impulse-response moving-average  
asked by Shaggi 1 vote

How does taking the absolute value of a complex signal reflect in the frequency domain?

I have a frequency-domain representation $F[n]$ of the complex discrete one-dimensional signal $x[n]$: $F=\mathcal{F}(x)$. Is there a frequency-domain transformation of $F$ into $F'=\mathcal{F}(|x|)$? ...

fourier-transform frequency-domain  
asked by kkm 1 vote
answered by Jim Clay 0 votes

How to extract IF (instantaneous frequency) from Discrete Hilbert Transform?

The continuous time Hilbert transform is $$\hat x(t) := x(t) + j\left( p.v. \left\{\frac{1}{t\pi} \ast x \right\} (t)\right)$$ where $$ \theta(t) = \tan^{-1}\left( \frac{ p.v. \left\{\frac{1}{t\pi} ...

filters discrete-signals transform hilbert  
asked by user27886 1 vote
answered by André Bergner 0 votes

Audio Recognition and Learning

I'm a beginner with absolutely no experience in signal processing, but it has been a long-term goal of mine to do something that mixes music (a hobby of mine) and computer science (my "expertise"). ...

audio signal-analysis machine-learning  
asked by Lycus 1 vote

Construct a correlation matrix using the covariance method

I want to compute the autocorrelation matrix by using the covarience method. X(n) is the harmonic process $X(n) = \sum\limits_{i=1}^3 A_i e^{jn\omega_i} + V(n)$ $V(n)$ is unit variance noise. $ ...

asked by DigiDude 1 vote

Direct Form I Filter from Direct Form II

I am looking a way to make outputs match. For len 160 wouldnt the error be significant? For 40 ? I have included some sample output showing the error. Direct Form 2 Original void highpass(const ...

filters c  
asked by Parhs 1 vote

Greatest hits from previous weeks:

What are linear and circular convolution?

I have some basic understanding of signals and convolution. As far as I know it shows the similarities of two signals. Could I get some explanation in plain English of: what are the linear and ...

asked by Sturm 3 votes
answered by Hilmar 1 vote

QPSK Modulation/Demodulation in C++

I'm trying to implement a QPSK Mod/DeMod system in C++. So far i have a bit generator that generates N bits and stores it into an array: srand(time(0)); for (int i = 0; i < N; i++) { ...

matlab modulation digital-communications demodulation qpsk  
asked by Brian 3 votes
answered by John -1 votes

Can you answer these?

Normalized cut segmentation output correct or not?

I have implemented "normalized cut" segmentation. The change here is that, instead of giving an image as input, I have given an matrix of image. As my output looks odd to me. I need to know whether my ...

image-processing matlab computer-vision image-segmentation  
asked by nikhilk 1 vote

Selecting the number of cycles for wavelet transform

I'm trying some wavelet analysis of EEG signals, using the phase lock measures from [1], specifically the S-PLV measure. In order to calculate that we perform a wavelet transform on the signals and ...

frequency wavelet  
asked by Bar 1 vote
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