Questions tagged [resampling]
The resampling tag has no usage guidance.
180
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Estimating spectrum with regularly missing samples from data
Suppose:
$$
s(t) = \sin(2\pi{f_0}t)
$$
Suppose I'm sampling the signal with a sample frequency $f_s >2f_0$ .
However, every $M$ samples there is a dead-time of $L$ samples.
Traditionally, the (...
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0
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1
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440
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Resampling to the same sample rate via Python
I'm working on machine learning model and tried to downsample WAV files with Python script, but it didn't work, so I made the simple version - script "resamples" WAV file from 44100Hz to the ...
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2
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102
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Effect of changing sampling rate of an audio signal
What will happen when sampling rate of an audio signal is changed? Does it changes signals duration or signals total sample or both?
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89
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Resampling a signal with variable sampling rate
I’ve created an upsample and a downsample functions (x2) using polyphase FIR filter.
I have a signal which comes in chunks where sampling rate of each chunk can vary between 1x and 2x (e.g. 48000 Hz ...
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votes
4
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954
views
Is adding a mean point between every two points a valid way of upsampling?
Suppose we need to double the sampling rate of an audio signal.
Is adding a mean point between every two points a valid way of upsampling? If no, then why not?
For example, in images, pixels may be ...
- 169
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23
views
Calculating the sample position for simulating the effect of gradually raising the playback rate
Suppose I have a sound recording of a tone whose instantaneous frequency keeps falling (continuously, not in steps) in inverse proportion to the running time -- i.e. the initial frequency is 1000 Hz, ...
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1
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1
answer
50
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Stringent filter requirements
I am trying to resample a signal using Matlab's resample function. The documentation explains that conceptually, it is upsampling by p, then applying an interpolation filter, then downsampling by q, ...
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2
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466
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Matlab "resample" function
Say I have a signal x(n) and I want to resample from rate 30Hz to 20Hz. In Matlab, I can make a filter with:
...
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0
votes
1
answer
80
views
Resampling in time
I have a huge dataset, way too much to be loaded into memory. I need to downsample the data to a new rate. Normally, this would consist of upsampling by N, applying FIR LPF, then decimating by M to ...
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1
vote
1
answer
76
views
Multiple questions about how to implement practical resampling
I am learning resampling theory, and for the time being I am specifically interested in downsampling. I have a textbook that is not a dsp textbook but has a section on resampling. The way they put it, ...
- 95
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74
views
Does the combined pointsample+bilinear upscaling algorithm have a name?
I have been performing digital image upscaling of pixel art in one of my hobby projects, and the two simplest upscaling algorithms are point sampling or bilinear upscaling.
Point sampling exhibits ...
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3
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568
views
How to align timeseries by decimating while preventing aliasing?
I have two pandas DataFrames, dfb and dfv, where dfb has a higher sampling rate than ...
- 179
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vote
1
answer
437
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Creating a polyphase filter
I need to design a 3/2 resampling filter using polyphasic filters. On my original filter I have coefficients $$h[n] = [a_0, a_1, a_2, a_3, a_4, a_5, a_6, a_7, a_8, a_9, a_{10}, a_{11}]$$ making it an ...
4
votes
2
answers
718
views
Resampling in frequency domain
I have a problem to solve, I need to get the frequency spectrum from the first plot, and then transform it into the second plot using resampling and filtering.
My thought process was, I can upsample ...
1
vote
1
answer
44
views
Frequency constraints on a down-sampled signal
I am preparing for an examination and am confused about one of the questions on the study guide. The question given on the study guide is given below.
We want to implement a change of sampling rate ...
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1
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164
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Resampling in real-time with non-integer ratio
I have a classifier that is trained on a dataset sampled at 100Hz. I am using this classifier on a MCU (the teensy 4.0 dev board) for inference and not training. However, the ADC chip I am using ...
- 123
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3
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726
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Convert Sample Rate of IIR Filter Coefficients
I have IIR filter coefficients and zeroes, poles for that filters. But all filters are generated with 192kHz sample rate. I have no other info about filter properties such as Fc or filter type or Q.
...
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39
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Oversampling of OFDM post-IFFT frame
I would like to build IQ radio waveform - first part - synchronisation sequence (ZC) and second part, OFDM frame with Cyclic Prefix(after IFFT).
I want to to oversample ZC sequence at transmitter, and ...
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2
answers
119
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Sample rate conversion of a complex bandpass signal
I have a complex bandpass signal. I need to upconvert it from 230.4 Msps to 245.75 Msps, i.e. by a factor of 16/15. What would be the best way to do it?
3
votes
1
answer
308
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java resampling implementation using sinc function
To be as succinct as possible, I've written a Java method that implements resampling of a signal using the sinc function interpolation formula. When I test this code with a simple sinusoid, I'm able ...
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2
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281
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Realtime sample rate conversion from variable source
Having all but given up on getting USB audio to work reliably, I'm looking now at taking the stereo 16-bit I2S stream from the Raspberry Pi 4's 40-pin GPIO header.
Unfortunately, that signal stops ...
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214
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Effect of sample frequency on deconvolution
I am a chemical engineer so I'm not very familiar with the methods of signal processing. Nevertheless I need to apply them now on my thesis work. Most recently a question occurred to me, that is ...
- 31
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96
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On-the-fly computation of a variable cutoff frequency polyphase resampling filter
I'm creating a polyphonic audio sample player and I want to let the user play each voice faster or slower using resampling by a rational factor (classical interpolate by L / decimate by M scenario), ...
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448
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True Peak detection
To measure True Peak, MathWorks's Matlab Help Center page suggests:
The signal is over-sampled to at least 192 kHz.
The over-sampled signal, a, passes through a ...
- 867
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81
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Downsampling a binary file
TEXBAT is a recorded dataset about spoofing scenarios for evaluating GPS signal authentication techniques.
On this project, there are recorded GPS signals stored as complex 16- bit samples at a rate ...
2
votes
3
answers
249
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Why are real-world digital images not bandlimited?
In the materials about image resampling, it always mentions that real-world digital images not bandlimited. However no explanation
is provided.
For example,
Sinc resampling in theory provides the ...
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votes
2
answers
82
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Image warping with heat map that "pulls" on pixels
I am looking for an efficient image warping function $$f: (\text{image}\in \mathbb R ^{M\times N\times3}, \text{heatMap} \in \mathbb R ^{M\times N}) \to \text{warpedImage} \in \mathbb R ^{M\times N\...
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59
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Representing changing sample rate in block diagram and frequency response plot
I have an discrete integrator which sums over a block of input samples to produce output samples at a lower rate.
The integrator sums a block of 8 input samples, multiplies the sum by a coefficient, ...
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1
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120
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Sinc Based Multi Dimension Signal Resampling on the Fourier Spectrum (DFT)
As a generalization of the following questions:
The Proper Way to Do Sinc Downsampling (DFT Downsampling) for Uniformly Sampled Discrete Signals with Finite Number of Samples.
The Proper Way to Do ...
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50
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Why does my field convert spatially anisotropic data to a spatially isotropic form as a part of preprocessing?
I've struggled to find any literature explaining this, so here's hoping someone can help out.
I work in a subfield of MRI where the data that we collect is 4D (3D spatial and 1D temporal). Due to ...
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582
views
Is it ok to resample impulse response?
I have some room impulse response at 48kHz sampling rate.
I have recording at 16kHz sampling rate.
I want to apply impulse response on the recording. What I do now is downsample impulse response 48kHz ...
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203
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How to upsample voice properly?
I have a low quality 24 kHz mp3 voice and I'd like to upsample it to 48 kHz for farther mixing with another ...
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0
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58
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Role of oversampling within resampling / pitch modification
I'm working on a pitch modification plugin involving resampling, and want the quality to be as high as possible.
I currently use windowed sinc interpolation and lowpass filter where required.
I ...
- 185
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149
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Downsampling a signal containing artifacts
I have 2 kHz-sampled signal that I would like to downsample to 256 Hz.
The original signal contains artifacts (= time intervals where data has too high/too low values. I know boundaries of the ...
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553
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Resampling pitch shifter
I’m trying to build a very basic resampling pitch shifter which reads samples from disk. I only want to change -+6 semitones without keeping the original sample length. I already have all the classes ...
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404
views
Does resampling to low number of samples lead to loss in high frequency content?
I am building an one dimensional Convolutional Neural Network and wish to feed it raw audio but it turns out that the number of samples is very larger. The audio was sampled at 48 kHz and the duration ...
1
vote
2
answers
197
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Frequency response of discrete time system involving interpolation and resampling
I am working on a problem towards calculating frequency response of discrete time system(does interpolation followed by resampling) which looks like:
x(n) is fed to linear interpolator(h(t) = ...
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vote
3
answers
70
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Theoretical considerations for Using Finite Arrays to Represent Samples of Signals of Infinite Length
Discrete signals can come from sampling continuous-time signals. A continuous-time signal can be of infinite support. For instance, a sin wave. In terms of mathematical description of signals and ...
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89
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What is the meaning of spectral contamination in image processing?
I resize the Multispectral image to perform IHS-to-RGB transformation. I used the Nearest Neigbour Interpolation method when resizing. While researching this issue, I saw that this is the best option ...
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538
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Streaming windowed sinc interpolation/resampling: trying to understand a Rust implementation
I'm working on a fork of the Rust dasp library, which is intended to be a DSP toolkit that abstracts over samples/frames/signals, and contains a number of functions ...
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1
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1k
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Python: Resample without equal
I would like to resample (downsample) a signal using python in order to get an even spacing and fill gaps.
About the signal:
It consists of a vector for y (amplitude) and x (timestamps)
Very slow; $...
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280
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Multiple choice on sampling and aliasing
I found some multiple choices in a well known book . The problem is that I don't get the answers in some and I want to do so.
Question 1:
The signal x(t) with Fourier transform $X(j\omega) = u(\omega)-...
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Remove noise introduced while converting a Delta-Sigma Modulated (DSM) signal into a pulse-code modulated (PCM) signal?
I'm writing a tool that converts a dsdiff audio file (dsd64) into a flac audio file (DSM -> PCM). The project is both a programming exercise and a signal processing exercise; I'm learning a lot ...
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382
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What are the 'phases' in this 2D scaler filter
I am pretty new to DSP and have been looking at how image scaling is done in hardware. I and came across a 2D scaler core for an FPGA here. I have read up a bit about polyphase filters, but am ...
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66
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draw sines at higher freq
I'm trying to plot some sine waves (code example in plain js here).
When freq is "low" (freq = 10 hz in that case), the plot is quite nice:
The problem ...
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1k
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Apply filter before or after Downsampling?
Context: I'm trying to do formant estimation. My first attempt didn't work out all that well so I'm trying to follow closely Praat since their formant estimation is remarkably accurate.
Question: I ...
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How do I change the sampling rate without changing the speed and pitch in Python?
I am building a voice recognition algorithm, and the use case specifies that it should be able to identify the targeted speaker from various audio sources, which means that it must be able to process ...
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1
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1k
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How to implement sinc interpolation
I'm trying to write my own high quality audio sample rate converter. I barely know anything about signal processing though so I need help.
From what I understand I need to sum together normalized sinc ...
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80
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How to transform a signal to go through specific points?
I have a 1d signal obtained using a Fourier based resample method (TDIFDZP) for which the resampled points don't necessarily go through the original samples. I want to transform the upsampled signal ...
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49
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Resampling with factor linearly moving from one value to another: calculate expected target length
I am resampling an audio (1D) signal, using a resampling factor that moves linearly from startFactor to endFactor; say the input ...
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