Signal Processing Stack Exchange Community Digest

Top new questions this week:

Impulse response of a time scaling system

Assume a bandlimited signal $X(t)$. Given that the output for this signal is $X(t/2)$, what will be the impulse response $h(t)$ of such a system? \begin{array}{l} X( \omega ) \ =\ \int ^{\infty ...

fourier-transform impulse-response scaling  
asked by user8206055 3 votes
answered by Matt L. 1 vote

Friendliest python library for fixed point algorithm simulation

My primary programming language is python. Is anyone aware of solid python libraries to simulate fixed point algorithms in python? A quick google search revealed this: ...

python fixed-point  
asked by rhz 2 votes

Using a low pass filter to interpolate signal

In my DSP university textbook, the interpolation process is described as follows: In order to represent a baseband signal $x[k]$ at an increased sampling rate with the same shapes of its ...

lowpass-filter interpolation  
asked by filaton 1 vote
answered by DSP Rookie 0 votes

Response of a system using DFT

Let's say that we have two sequences, input sequence $x(n) = [0121]$ and impulse response of a given system $h(n) = [0, 1, -1, 1]$. I need to find response of this system to given input sequence. ...

dft convolution  
asked by cdummie 1 vote
answered by DSP Rookie 2 votes

Find a LTI system such that $\mathcal{T}\{\frac{\sin t}{t}\} = \frac{\sin 2t}{t}$

Let $x(t) = \frac{\sin t}{t}$ and $y(t) = \frac{\sin 2t}{t}$. Is it possible to find a LTI system such that $\mathcal{T}\{x(t)\} = y(t)$? If not, what's the reason for that? My try: Assuming ...

continuous-signals linear-systems frequency-response impulse-response  
asked by S.H.W 1 vote

Calculate the difference of the magnitude of discrete fourier transform - help inimplementing the formula

I have a time-series of length N generated by the following equation: x(1) = 0.1; for jj =1 : 500 x(jj+1) = 4*x(jj)*(1-x(jj)); end The functional form of the equation is x[n+1] = ...

image-processing matlab fft fourier-transform ifft  
asked by Sm1 1 vote

Degrees of freedom in coding (for a communication channel)

I was reading on my lecture slides about how to achieve diversity (i.e. transmit more copies of the same message in order to avoid its corruption; this technique may be realized by repeating the ...

signal-analysis digital-communications fading-channel channelcoding channel  
asked by Kinka-Byo 1 vote

Greatest hits from previous weeks:

How can I generate a sine wave with time varying frequency that is continuous, in C?

How can I generate a sine wave with time varying frequency that is continuous? How can I resolve the following problem? I want a continuous graph. I'm generating this simply like this: for(int i = ...

asked by deltafft 10 votes
answered by ederwander 13 votes

Gaussian Blur - Standard Deviation, Radius and Kernel Size

I've implemented a gaussian blur fragment shader in GLSL. I understand the main concepts behind all of it: convolution, separation of x and y using linearity, multiple passes to increase radius... I ...

image-processing gaussian blur  
asked by LodeRunner 22 votes
answered by Tarin Ziyaee 21 votes

How to Remove a Glare / Clipped Brightness from an Image?

I have an image Is there any way of removing the bright white spots ? Please help thanks Edit: After operating with gaussian and then displaying using imagesc get the following output which ...

image-processing matlab image-restoration  
asked by vini 21 votes
answered by Matthias Odisio 19 votes

Calculate symbol rate for QAM modulation

Not sure if this is the right place to ask, feel free to move it if any other site suits this better. Anyway I am referring to QAM modulation used in US Cable TV. I know it comes under Annex B which ...

modulation channelcoding  
asked by bobby 3 votes
answered by Jim Clay 7 votes

What does frequency domain denote in case of images?

I was just learning about the frequency domain in images. I can understand the frequency spectrum in case of waves. It denotes what frequencies are present in a wave. If we draw the frequency ...

image-processing frequency-spectrum dft  
asked by Abid Rahman K 115 votes
answered by Niki Estner 97 votes

Is a notch filter for 50 Hz without delay possible?

I am processing an EEG signal (2 kHz sampling frequency) from hardware and the built-in filter doesn't work as intended. FIR gives a delay, and IIR is unstable. The signal of interest is from ...

filter-design delay  
asked by Evil 13 votes
answered by Dan Boschen 19 votes

Kalman filter - understanding the noise covariance matrix

What is the significance of the noise covariance matrices in the Kalman Filter framework? I am referring to: process noise covariance matrix Q, and measurement noise covariance matrix R at any ...

filters noise kalman-filters tracking  
asked by Raaj 12 votes
answered by Roger Labbe 17 votes

Can you answer these questions?

Finding the system output by convolution

pretty new to this concept, so do bear with me. A linear dynamic system is described by the following differential equation: Transfer function H(s) is calculated to be = I've already found the ...

convolution linear-systems laplace-transform math differential-equation  
asked by Jisbon 1 vote
answered by Matt L. 0 votes

symbol synchronization

PLL is typically used in carrier synchronization and its diagram is well known, consisting of a multiplier, a low pass filter, and a VCO. In "Phase-locked Loop" at wiki ...

digital-communications demodulation pll symbol-timing  
asked by Cindy 1 vote

What is Maximally Stable Extremal Regions (MSER)?

In the paper , MSER is being defined. Please help me understand what is MSER and how to implement it. The paper says, The regions are defined solely by an extremal property of the intensity ...

image-processing image edge-detection  
asked by alyssaeliyah 1 vote
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