# Tagged Questions

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46 views

### How to estimate THD?

I have a signal source that I can digitise and read. It produces mainly a 50Hz sine wave, but there is distortion as well. I'd like to estimate the total harmonic distortion for this signal. I've ...
32 views

### What could be the cause of this audio effect?

I'm working on VoIP application and at the moment the sound received from the other user is like this: Since there could be a myriad of reasons for this issue, debugging ...
48 views

### how to get an input test signal for convolution/ distortion method

i am trying to do some experiments with Total Harmonic Distortion. According to ...
56 views

### STFT on audio signal

I am trying to implement a STFT on audio signal as an exercise, and in order to do real-time filtering if I can get the "sound->STFT->inverseSTFT->reconstructed sound" chain to work. What I do for ...
77 views

### FFT Convolution: missing sample somewhere

For a piece of software I've been working on lately I need to implement FFT convolution for performance reasons. Doing so has been mildly succesfull but there is still a error somewhere causing lots ...
26 views

### Most efficient/sparsest piecewise linear approximation of signals

When standard linear regression is becomes unefficient, Piecewise Linear Regression Models are sometimes preferred over Polynomial Fits for tractable sigmal models. Indeed, they should be called ...
68 views

### Quantitative comparison of scaled-, delayed- and warped-signals

In several signal processing techniques, such as blind source separation (BSS) or deconvolution, one may wish to estimate a signal $x(t)$ and recovers $s.x(t+d)$, where $s$ is a scale factor, $d$ a ...
125 views

### Vinyl Crackling Effect

I want to know how can I achieve this effect: https://www.youtube.com/watch?v=DQg9M_47c3A Do I need to use a filter? And what can I use for the crackling, poping effect? Thanks in advance!
87 views

### Distances In a Single Image With Some Real References

Consider following image: We have some real references here: Stonehenge measurements (stone dimensions and distances), some strait lines at the back of carts, cart wheels that are almost of the ...
159 views

### How to estimate radial distortion from lens characteristics?

Is there a way to estimate the radial distortion coefficients without calibration, given the lens characteristics, such as its diameter and its focal length? Typically for camera calibration a ...
88 views

### Slight crackle with overlap-add frequency-domain convolution

I'm trying to make an FFT audio filter using overlap-add but there's some slight rhythmic distortion/crackle in the output. I have an irSize (impulse response size) of 512 samples and a blockSize of ...
105 views

### Can sample aliasing of strictly white noise lead to random walk (drift) in the sampled signal?

Aliasing of tones higher than the Nyquist frequency, and where the tone may have some degree of nonlinear distortion can appear as low frequency 'drift' or even near static bias in the sampled signal. ...
35 views

346 views

### importance of symmetric windows for STFT for practical applications

I am wondering why is the linear phase property of filters with symmetric coefficients important for some practical applications of short time fourier transform, such as image processing? I have read ...
597 views

### How to calculate Noise and distortion of an image?

I need to make an application in iphone which needs to calculate noise, geometric deformation other distortions in an image. How to do this? I have done some image processing stuff with opencv + ...
4k views

### Add odd/even harmonics to signal?

How do I add odd or even harmonics to a floating point signal? Do I have to use tanh or sin? What I'm trying to do is achieve some very simple distortion effects, but I'm having a hard time finding ...