Signal Processing Weekly Newsletter

Signal Processing newsletter

Top new questions this week:

Is it possible to design noncausal filters in Matlab?

I'm trying to design a lowpass IIR filter with 5Hz cutoff frequency (sample frequency is 200Hz). i know how to create it with fdatool, or with functions such as 'butter' or 'ellip'. However, i think ...

asked by lorenzo0820 3 votes
answered by Matt L. 4 votes

Implementing overlap add method for convolution with a slice of the filter

In overlap add method for convolution a filter $x$ of length $M$ will get convolved with a signal $y$ of length $N$ where $M << N$, i.e., $z = x * y $. Here the signal $y$ is sliced into ...

matlab convolution  
asked by Vinod 3 votes
answered by Mark Borgerding 4 votes

When calculating the Nyquist frequency should carrier frequency be included

This isn't my field, so please forgive any misnomers on my part. I'm looking into buying a amateur radio receiver, and I'm thinking about what sampling rate I need. I'm most interested in satellite ...

asked by FraserOfSmeg 2 votes
answered by MBaz 2 votes

Effects of DC offset on a signal

What are some of the reasons why DC offset is considered undesirable for a timeseries signal other than wastage of power during transmission ? Specifically, How does it cause spectral leakage and out ...

discrete-signals signal-analysis continuous-signals  
asked by Naveen 2 votes
answered by rrogers 1 vote

convolution matrix for image scaling

Is there any way how to compute convolution matrix for Nearest Neighbor (bicubic, bilinear) image scaling (upscale/downscale)?

image-processing image convolution  
asked by thomas 2 votes
answered by Mikhail 0 votes

BandPass and StopBand FIR filters (Hamming) is not working

I have two groups of 3 frequencies of tone (music), First Group Tones: 39 (77.7817 Hz), 40 (82.4069 Hz) and 41 (87.3070 Hz). Second Group Tones: 83 (987.7666 Hz), 84 (1046.5022 Hz) and 85 ...

filters window-functions bandpass finite-impulse-response  
asked by chepe lucho 1 vote

Sub pixel shift causes weird results

I am trying to shift an image on a subpixel level, with the method described here: ...

fft image python  
asked by 317070 1 vote
answered by hotpaw2 -1 votes

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

Why is the Fourier transform so important?

Everyone discusses the Fourier transform when discussing signal processing. Why is it so important to signal processing and what does it tell us about the signal? Does it only apply to digital signal ...

asked by jcolebrand 58 votes
answered by Lorem Ipsum 81 votes

Can you answer this?

Analytical expression for convolution of two 2D DFTs

I am trying to do an image analysis problem on some images, and I want to calculate some things in the frequency domain which are giving me problems. Say I have an (discrete) image $I(x,y)$ of size ...

image-processing dft convolution  
asked by A. Kennard 1 vote
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