The 2024 Developer Survey results are live! See the results

# Questions tagged [distortion]

The tag has no usage guidance.

90 questions
Filter by
Sorted by
Tagged with
1 vote
21 views

### Correct geometrical distortions from camera

I have video recordings of a behavioral experiment on mice. The camera is rigidly attached to the ceiling. Below the camera is a round table with round holes. Unfortunately, the camera is not strictly ...
• 147
12 views

### How does camera intrinsic parameters change after undistortion

Here is my goal: I have used OpenCV to estimate a camera's intrinsic parameters and distortion coefficients. In order to avoid having to deal with the camera's distortion going forward, I would like ...
42 views

### What measures are used to identify a faulty speaker?

I'm working on building a mobile app that would play a sound via speaker, record itself and process this recording to identify faults within speakers, what meastures or parameters should be considered ...
38 views

### Can a bad quality sound be measured via THD?

I'm trying to create an app that measures the audio quality, this is ideally to filter out blown out or cracking speaker who has different types of distortions, what would be the best measurement ...
23 views

### Constraints in Dynamic Time Warping for Speech

The Dynamic time warping is applied for time normalization. As shown in the diagram, two different signals with $Tx$ and $Ty$ time instants, are time-normalized to have $T$ time instants. $\phi$ is ...
106 views

### What exactly is transmitted in the channel in lossy compression?

Consider the problem of lossily compressing a memoryless binary source $X \sim \operatorname{Bernoulli}\left(\frac{1}{2}\right)$ at target Hamming distortion $D < \frac{1}{2}$. According to the ...
• 125
96 views

### Distortion-Rate function for standard Gaussian signals quantized with a uniform alphabet

Let's say $X \sim N(0, 1)$ is a standard Gaussian input signal and $Y \sim U\{y_1, y_2, \cdots, y_{16}\}$ follows a discrete uniform distribution (in fact, $\{y_1, y_2, \cdots, y_{16}\}$ is a ...
• 125
31 views

### Channel Estimate for OFDM shows distortion for first last order samples

The Channel Gain Estimation was obtained using Least Square method as follows: Hk= mean(Rx_LTS ./ Tx_LTS, 2); k= -26 to 26 Where Rx_LTS is the received long training sequence (52 samples after ...
• 41
104 views

### What kind of distortion effect is this?

Here is the image of a plugin distortion I have applied to a sine wave. The sound characteristic is heavily distorted and digital but still good sounding bass wave. Any ideas what kind of distortion ...
• 111
97 views

### Stream gate - removing samples from timeline. Pitfalls?

I'm working with gnuradio. What I want achieve is extract signal from full stream by some kind of stream gate (based on tags) and after that write to file only timeline where signal exists. In my case ...
• 1
1 vote
82 views

### Is this a noise or what? (Sinusoidal signal frozen for a short time)

I am studying a pair of AC signals for voltage and current. In a long run, I found a distortion happening as shown in the attached picture. I want to understand what could possibly have happened in ...
• 113
132 views

### Calculating THD vs. Frequency of an Acoustic System using the Exponential Swept Sine Method

I am working on analyzing the total harmonic distortion (THD) vs. frequency curve for an acoustic system. I am aware of the traditional method of exciting the system with a mono-frequency wave and ...
• 527
1 vote
346 views

### DSP function used by musical distortion plugins

In short: what kind of mathematical function was applied to this sine WAVE? I am trying to implement my own distortion plugins. Amongst other things I have read several chapters of Will Pirkle's book (...
687 views

### How to avoid harmonic distortions in a DAC?

I have a DAC which is assumed to be nonlinear, such that it produces unwanted harmonic distortions at integer multiples of the input frequencies. (EDIT: Any other nonlinear distortions, such as ...
• 183
278 views

### Troubleshooting distortion in room impulse response measurements:

I am collecting data for a project, where I am measuring the room impulse response by playing a sine sweep from a speaker (QSC K8 1KW Active Loudspeaker) and measuring it from the other side of the ...
1 vote
59 views

### WAV file audio sync/distortion issue

I was using Scarlet 2i2 audio interface plugged into an Android phone. Monitor headphones on the interface sounded great! I recorded a WAV file of a kids' concert with the USB Audio Recorder Pro app, ...
41 views

### Strange Look to Sampled Sinusoid [duplicate]

Ok so as part of a project for school I have been designing an FIR bandpass filter. The output should have been a signal which looks like a sampled sinusoid but there was a strange alteration on the ...
1 vote
88 views

### Nyquist frequency Plotting Distortions

I'm trying to plot some sinusoidal signals in Matlab. But while frequency is getting higher (closing to fs/2), results are getting distorted. I guess it's lack of my knowledge but distortion is ...
55 views

### Fixing distortion in photographic reproductions

I am currently building a photographic setup which I intend to use to make reproductions of a large amount of transparencies(positive and negative film strips). As I will be using a fairly small (1&...
• 103
273 views

### Advice on seperation of impulse responses for harmonic distortion orders

I am working based on Angelo Farinas paper: Simultaneous measurement of impulse response and distortion with a swept-sine technique. The purpose of the work is part of a loudspeaker measurement and ...
• 31
429 views

### Group delay compensation for non coincident drivers

Suppose I have a two-way speakers system which can be modeled as a two-way Linkwitz-Riley crossovers network with impulse responses $h_{lp}(n)$ and $h_{hp}(n)$. I would like to equalize the group ...
• 57
204 views

### What happens when filter ringing is far longer than the signal itself?

I'm digging into some (quite popular in my field) analytical practice that I find suspicious. The problem is to remove the trend from some very short (eg. 18-40 data points representing 200 - 800 ms) ...
102 views

### Signs of waveshaping polynomial coefficients

I'm playing with some basic functions for distortion purposes. Odd order polynomials generate odd harmonics, even order polynomials generate even harmonics. When I combine them, both types occur at ...
1 vote
61 views

### Deconvolution of signal with harmonic distortion

I came across these measurements done using a stepped sine sweep covering only some frequencies (~800 frequency points). I would like to get an impulse response from these measurements to convolve ...
• 11
141 views

### Emulating tape distortion of low-level audio signals

I'm working on a tape echo emulation in Reaktor, and I've based the frequency response, tape speed warble, high-amplitude saturation and tape hiss on a paper I found about the Roland Space Echo. ...
70 views

### Error correcting code? - using RGB space with a lookup table

This problem could be thought about as how to transmit a signal with 3x8bit RGB in a way that is robust to the distortion of antialiasing blends colors. The context: I need to rewrite a short utility ...
70 views

### High FIR order in time critical classification task

I have a question regarding filtering (bandpass in my case) as a preprocessing step before a classification task. The frequency band I am interested in lies between 0.5 - 22 Hz which results in a ...
1 vote
278 views

### Can harmonics be created or simulated a la carte

I am trying to learn about adding harmonics (audio) with a goal to make a plugin that can allow adjustment of the amplitude of each harmonic being added. I would not have the ability to write this but ...
1 vote
113 views

### Fixing integer overflow in wave file

I have this recording from my DAW that showed a strange form of distortion: the signal clipped at many places, but instead of simply being clipped (loss of information), somehow the integer value of ...
• 113
134 views

### Finding the Transfer Function of a Multiplicative Distortion in MATLAB

I have the frequency response of two signals shown above. One is uncontaminated, and the other is the same signal contaminated by a multiplicative distortion with two poles and two zeros. I need to ...
• 53
1k views

### How does image rotation affect the intrinsic camera parameters?

I am considering the problem of how to (manually) change camera model parameter to make it "valid" on a rotated image. This question tackles resizing, but does not consider lens distortion. ...
• 81
426 views

### Exponential Swept Sine Distortion

I was able to get passable results on fundamental measurements using and exponential swept sine. Now I am trying to get distortion information from the same measurement but am puzzled by the results. ...
1 vote
61 views

### Signal distortion under non-linear channel

The channel is given to have these characteristics, and its required to study the affect on Frequency Modulated signal and its demodulation. Since there are no sharp corners (like during clipping) ...
1k views

### What function to apply a Metamorphopsia (grid warp) translation?

How would I go about finding or creating a function to warp images dependent on grid lines surrounding an origin (I don't wish for a grid on my actual images): It should work in practically the same ...
169 views

### Understanding legacy code: Algorithm to remove radial lens distortion

The method below to remove lens distortion from a camera was written more than ten years ago and I am trying to understand how the approximation works. ...
204 views

### Total Harmonic Distortion THD for the rectifier

I have a circuit with rectifier and this cause the non-linearity and consequently harmonic. I show it on the oscilloscope and then collect the signal from the oscilloscope to the computer by using the ...
488 views

### Group Delay for Hilbert Transformer and Resulting Dispersion

An ideal Hilbert Transformer shifts the phase for all positive frequencies by $-\pi/2$ and all negative frequencies by $+\pi/2$ while maintaining constant magnitude everywhere. Group Delay is the ...
• 53.1k
233 views

### How to quantify phase distortion of a filter specific to a signal?

For example, a EKG input signal is filtered with a known transfer function that does not have linear phase. How do you quantify the phase distortion of the output signal given you have the input? I ...
• 15
1 vote
1k views

### How to prevent distortion after down-sampling?

I am new to audio signal processing, but in one of my machine learning projects that I am working on, I need to down-sample my audio somewhere in the middle of my neural network. Therefore, I need a ...
• 131
1k views

### How to measure SINAD of an audio signal?

I tried to measure the SINAD and SNR of a recorded audio signal using MATLAB. The following is the process I did to measure the 2 parameters: Firstly, I generated an FM modulated signal(1 kHz audio ...
• 1
272 views

### Distort voice to hide talker identity as much as possible

I need to develop an app which makes speech recognition. Because I need to be able to constantly improve the recognition capability, I would like to train the engine with real recordings and match the ...
• 21
275 views

I am interested in buying a device that measures the SINAD of the audio signal(FM signal) that I receive from PC. Here is the setup: Signal generator (generating 1kHz FM signal ) $\rightarrow$ ...
• 1
21 views

I am interested in buying a device that measures the SINAD of the audio signal(FM signal) that I receive from PC. Here is the setup : Signal generator -> attenuator ->HackRF connected to PC with SDR# ...
• 1
1 vote
835 views

### Linear vs Non linear distortion

I'm learning about distortion and I got stuck at "What is the difference between linear and non-linear distortion?" (Also in frequency spectrum i.e. Amplitude and phase spectrum)
1k views

### Precise 5th and 7th harmonics of a sampled sine wave

Does anyone know in decibels (to 1/100th of a dB) what the theoretical 3rd, 5th and 7th harmonic of a 0dB fs 24-bit (i.e. full-level; 0dB = -8,388,607 to 8,388,607) sampled sine wave without dither ...
• 101
1 vote
670 views

### Can I use SINAD for THD+N measurements? Are they inverse of each other?

I'm looking for a clarification, which I haven't really been able to find. It's probably obvious but I'd like to be absolutely sure of what I'm calculating. I noticed that the formula that calculates ...
• 129
61 views

### Audio sounds oddly distorted [closed]

https://clips.twitch.tv/TangentialObliqueLobsterSaltBae https://clips.twitch.tv/CharmingBashfulAlfalfaRickroll https://clips.twitch.tv/NaiveKindGorillaGivePLZ (Disclaimer: These were not recorded on ...
316 views

### Finding the memory polynomial model coefficients

I want to build a memory polynomial model given that I know the corresponding output signals for known input signals. What is the easiest way to find the coefficients of it? And how do we take the ...
531 views

### Dithering adds harmonic distortion after filtering and upsampling

I have an issue which I wasn't able to solve for a few days. I have implemented a polyphase FIR interpolation filter within an FPGA which does interpolate by a factor of 8 or 16 times. I do accept an ...
• 33