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Sense of zeropadding in a time domain

I have the task related to Radon transform which contains a subtask which uses resampling by means of DFT. Let's consider the non-periodical discretized signal (Fig.1) (for example the string of pixels) having 515 pixels length. In my…
Roman Shkarin
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Why can Quadrature Demodulation demod a Frequency Modulated Signal?

I use a Quadrature Demodulator in my SDR application, which is defined as: $\angle (S_n, S_{n+1})=arctan(S_{n+1}*\overline{S_{n}})$ So practically its amplitude is the angle between two Samples $S_n$ and $S_{n+1}$ where $n$ refers to a position in a…
Marius
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What are your tips for DSP self-study?

Perhaps a meta-question, but I'll post it here because some of you are bound to possess gold nuggets about continuing education. It might be closed for being subjective but I don't care because this community is small and this could be valuable info…
panthyon
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Gaussian Filter Close to Image Border

When applying Gaussian filters close to the borders of an image, algorithms usually zero-pad or replicate/mirror/wrap the borders. This is not good enough for my case, so I wonder if there is something better out there. As the idea of smoothing is…
serigado
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Discrete (Inverse) Haar (2D) transform implementations

I am interested in implementations of the Haar transform, and its inverse, such that when composed always result in the identity operation. My inputs are discrete ordinals within a given range - and I need the output of the Haar transform to be…
aSteve
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Is there a condition for bandpass sampling?

Consider a signal that has lowest frequency component $F_l$ and highest frequency component $F_h$. According to the theory of bandpass sampling, this signal can be sampled and succesfully recoverd if sampled at a frequency ($F_s$) twice the…
srk_cb
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Convex Optimization in Signal and Image Processing

In signal processing, convex optimization plays a useful role in problems such as sparse signal recovery and filter design. What other places does convex optimization appear? For example, in compressed sensing the Basis pursuit Denoising problem,…
curiousStudent
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Sampling of band-limited white noise

The context is communication where we have a front-end that samples a signal and a noise (but here we focus only on the noise). My goal is to determine the noise power that I should use to simulate (in Matlab) the discrete noise after the ADC. This…
Jérôme
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How to test digital filters?

First the question(s): How should I write unit tests for a digital filter (band-pass/band-stop) in software? What should I be testing? Is there any sort of canonical test suite for filtering? How to select test inputs, generate expected outputs,…
heltonbiker
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Can we do cyclic prefix with zeros in OFDM rather than with samples from end of the ofdm symbol?

considering an OFDM symbol of x(0)x(1)x(2)x(3)x(4)....x(n-2)x(n-1)x(n). To perform cyclic prefix we prefix some samples from end of this OFDM symbol to the beginning of the OFDM symbol, like x(n-3)x(n-2)x(n-1)x(n)x(0)x(1)x(2)x(3)........…
srk_cb
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Match Filter in Time-Frequency domain instead of just Time domain. Redundant, or better?

Assume you have a signal, and within it, some pulses are present. A pulse is a simple tone. You know the pulses' duration and shape. (Let us assume that a pulse is made of a couple of cycles, and then to which all those cycles are multiplied by a…
Spacey
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Is it possible to do single vehicle tracking using Fourier transform?

I am working on a project in image processing which is based on importance of phase only reconstruction of a signal obtained using Fourier transform.For more information about phase only reconstruction,you can see the answer given by geometrikal in…
sagar
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BPSK vs $\pi/2$ BPSK, what the benefits?

I have come across modulation techniques that have $\pi/2$ phase shifts from the regular constellations. For example $\pi/2 $ BPSK vs constellation the regular BPSK. Other examples include $\pi/2 $ QPSK vs. QPSK I am wondering what are the benefits…
Tyrone
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1D Deconvolution with Gaussian Kernel (MATLAB)

Suppose that I know the output and the transfer functions of a system and I would like to calculate the input function using deconvolution. To get a grasp of the idea I have created a simple demonstration using Gaussians. As a sanity check I first…
user26609
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Demonstrating the effect of aliasing

How does the signal look when we don't use the Nyquist rate to remove aliasing from a signal during sampling? Let's suppose the signal is sinusoidal, with a frequency of 500 Hz and an amplitude of 2. signal = 2*cos(2*pi*500*t) If I sample it,…
Sufiyan Ghori
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