Questions tagged [resampling]
The resampling tag has no usage guidance.
122
questions
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2answers
43 views
Resampling of DTFT
I have a constant digital signal that is 1 for every sample and of length 4.
4 point DFT coefficients are $$[4,0,0,0]^T$$ Obviously. I wonder, if I resample the DTFT such that samples are taken at $$...
0
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0answers
38 views
Composition of interpolation and decimation matrices
I understand that interpolation is a linear transformation of a signal vector that combines interleaving the elements of the input vector with zeros followed by a filtering operation to remove any ...
0
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1answer
40 views
How to Emulate Sample Frequency Offset for OFDM in Matlab?
I am studying the effect of sampling frequency offset on OFDM, and in order to emulate SFO, I have to slightly change the sampling rate of the signal. In order to have a +5ppm offset, I have to change ...
0
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0answers
23 views
resample interpolation decimation filters algorithm
I'm creating a program in order to perform Resample, Interpolation and Decimation Frequency.
...
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0answers
45 views
Weird resampling artifacts of a periodic signal
I am trying to grab time series data from a database storing data on a propritary format. When i chose a resolution which is not a multiple of the power of two of the sampling resolution i get these ...
0
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1answer
19 views
Decimating by last interpolating factor? (Multi-stage)
Let's say I have a multi-stage interpolator at the transmitter, which interpolates by 2, 4 and 8 (that is, 64). When decimating (at the receiver) why should I start decimating by 8, then 4, then 2, ...
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0answers
26 views
Where to do timing synchronization?
I'm trying to do timing synchronization. I was wondering where in the receiver chain I should put this.
At the moment, I have (in order, so the first thing in the receiver is 1 and the last is 4):
...
0
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1answer
111 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 ...
0
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0answers
36 views
Interpolation FIR filter Remez design criteria
I want to upsample an audio signal by a factor of 8.
The technique I was going to use was to upsample by zero stuffing and then interopolate using a low pass anti-aliasing FIR filter designed using ...
0
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0answers
42 views
Delay of non-polyphase vs polyphase FIR filters
I implemented a polyphase filter function for interpolating and decimating. It works great (I compared it to what I'd get by interp/decim by inserting L-1 zeros and I get the same results) except for ...
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0answers
96 views
Polyphase resampling delay
I want to implement polyphase resampling.
For this, I wrote a script in matlab.
The script performs the following sequence of actions:
...
1
vote
3answers
253 views
Resampling and removing high frequency noise?
I am currently working on a simple sampler that will allow me to load in a wav file and use my MIDI keyboard to play the loaded wav sample at the frequency according to the note played.
Now I need ...
0
votes
1answer
59 views
Upsampling and pulse duration
How does upsampling factor relate to pulse duration?
If I want to do pulse shaping and I have rcosdesign(beta,span=8,sps=4) should I upsample by ...
3
votes
1answer
164 views
Optimal trade-off between oversampling and filter length
For some sampling-frequency-preserving operations on Nyquist–Shannon sampled signals, such as:
a shift a.k.a. translation, and
differentiation by applying a derivative filter a.k.a. gradient filter,
...
1
vote
1answer
29 views
Method to rescale signals to mean length
I have a set of signals of varying lengths. I have provided an example of the same below -
Their lengths vary between 186 to 202, with a mean length of 197. I am looking to rescale them to the mean ...
1
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0answers
19 views
Converting the equalizer coefficients from VSA at 2 sample/Symbol to 1.5 sample/Symbol
I was looking for some feedback on conversion of equalizer/filter coefficients at different sampler rate.
Problem Statement:
We have built a transmitter system whose output is at 1.5 sample/symbol (...
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0answers
134 views
Understanding Upsampling Filter in Laplacian Pyramid
For the construction of a laplacian pyramid, images are downscaled and then upscaled again. My question is what is a wise decision of the kernel mask for the upscaling task ?
In more detail, lets say ...
4
votes
3answers
415 views
Absolute convergence of periodic sinc interpolation
An $N$-periodic complex discrete-time sequence $[x_0, \dots, x_{N-1}]$ can be resampled to an $M$-periodic sequence $[y_0, \dots, y_{M-1}]$ with $M>N$, using sinc interpolation:
$$\begin{align}y_m ...
1
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0answers
103 views
Why do I have to scale filter coefficients during bandlimited sample rate conversion?
I am writing an example for how to perform sample rate conversion using windowed sinc and polyphase filters.
Here is the C++ code as a github gist.
So far, this works, and I think I have understood ...
0
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0answers
30 views
delayed result in sinc upsampled signal
I have implemented an infinite kernel sinc interpolation.
For some signals I notice an artifact, visible at the right end of the plot.
I am wondering: is it a bug in my code or a phenomenon usual for ...
1
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0answers
230 views
signal interpolation (upsampling) by factor 2
The task is to interpolate the signal by increasing the sampling rate by factor 2.
Matlab has a dsp.FIRHalfbandInterpolator function.
Let's try using it.
...
0
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1answer
271 views
Extrapolate a 2D array using Fourier Transform
I need to extrapolate a given 2D array to a larger domain, keeping the spatial frequency. This is the original field:
(the data file in numpy npz format and a Jupyter notebook to plot it can be found ...
0
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0answers
53 views
How should I modify my filter coefficients for the filter to be unaltered, when I change my sample rate
I am guessing this is a commonly encountered problem, but I am lost on how to really solve it.
I have FIR filter coefficients that are used to match the frequency response of data sampled at 3 kHz. I ...
1
vote
1answer
208 views
Best way to resample an OFDM signal without interpolating + filtering?
I am working on a custom transceiver with a sampling rate of 3.84 MHz (256 OFDM subcarriers at 15 kHz, although 56 subcarriers are null). I would like to resample the signal to 5 MHz, in order to use ...
1
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1answer
125 views
Is it possible to lose half the samples, and yet see the full spectrogram as the original signal?
Consider an speech audio signal sampled at 16,000 samples per second. Plot its spctrogram.
If we delete every other sample from input signal, we get y[n] = x[2n] for all n.
It seems that if we plot ...
0
votes
1answer
82 views
Having Glitches trying to use a Sinc Function Interpolation on a Signal, by chunks of 1024 samples
I am trying to interpolate a signal using a third party lib that performs Sinc Function Interpolation on a signal. It works well if I input all the samples at once but introduce phase distortion if I ...
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0answers
124 views
Matching two signals with small time drift
I have two time-domain signals sampled at 100 Hz that were measured using two different oscillators and therefore have a time drift between them. I have two synchronization points, one at the start ...
0
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1answer
521 views
The condition in order to not loose information after upsampling and downsampling [closed]
If you have a signal x[n] and it is upsampled by N and then downsampled by M. what is the condition for not losing any information in x[n]
0
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1answer
848 views
Resampling from variable to fixed-rate [closed]
I have a gyroscope which reports x,y,z values to my embedded device.
The rate that one sample appears is variable and has a jitter of around 10ms.
However I later want to have a log file with a fixed ...
0
votes
1answer
347 views
Convert 96 Khz to 48 Khz audio: is this simple downsampling method ok?
I have an audio signal x sampled at 96 Khz. I have already lowpassed it with a cutoff somewhere between 20 Khz and 22 Khz, so there should be nothing left of ...
0
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0answers
119 views
Resampling or interpolating non-uniform 2D measurements
I am not sure what I should call what I am looking for, but I have some measurements that have 2 independent variables and I would like to get an interpolated value at a specified x,y coordinate. My ...
2
votes
0answers
54 views
How can I extract the 2 polyphase components of a signal after sampling at the half of sampling rate
Suppose I have a continuous signal x(t), which was sampled using sampling function s(t) whose sampling rate is Ts.How can I sample the continuous signal by Ts/2 instead of Ts in order to get two ...
0
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3answers
122 views
Various size arrays interpolation - resampling
sorry if it's stupid question but it’s third day that I try to figure it out how to do that. And just can’t find the solution.
Let’s say I have array $A$ size 4, and $B$ size 8. And I need to put/...
2
votes
2answers
323 views
How can I synchronize signal from an LED and TTL pulses better?
I would like to synchronize my video and voltage data using Python. (I obtain these data using Bonsai and Open Ephys for an open field exploration experiment.)
I sent $150\text{ ms}$ long TTL pulses ...
0
votes
2answers
502 views
Signal Resampling by a non integer factor with convolution
to start I am a newbie in signal processing, I just started a month ago so please be as detailed as possible.
From what I understood to resample a signal by a non integer factor you can do an ...
0
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1answer
159 views
Downsampling in MATLAB - why scaling filter coefficients?
Trying to undertsand how MATLAB does resampling, looking at toolbox/signal/resample.m.
This is the part where (downsampling) filter coefficients are calculated:
<...
0
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0answers
83 views
Length of a resampled audio signal
It seems to me intuitively if I have a signal $y$ with sampling frequency $f_0$, then if I resample that signal with $f_{new}$ the correct number of samples will be $\frac{f_{new}}{f_0} \cdot len(y)$.
...
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2answers
175 views
Resampling with and without replacement for estimating significance of spectral components
In order to test the significance of spectral components, it seems reasonable to randomly sort the data in order to destroy all the serial correlations / spectral order e.g. 100,000 times, and then ...
1
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1answer
496 views
Computational Complexity of Polyphase Resampling
does someone know the approximate computational complexity of a polyphase resampling algorithm?
I am trying to find a good argument to prefer a polyphase resampling of Scipy over the FFT resampling ...
2
votes
1answer
906 views
How do I resample an audio signal without altering its pitch?
I'm working on concatenating videos again, this time with different playback speeds. The video stream part is easy enough, but the audio part is what's stumping me at the moment.
Currently, I've ...
1
vote
1answer
3k views
Python, resampling tools dont work as expected
I've tried both using scikit.samplerate.resample and scipy.signal.resample. With neither of them can I achieve the result I want.
Scipy.samplerate:
...
0
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0answers
84 views
Non-uniform resampling - spacing between output samples given speed factors
I'm working on an implementation of time-varying resampling in python. I've got the windowed sinc interpolation itself working nicely, but can't figure out where exactly to sample my input data for ...
0
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0answers
154 views
Playrate change based on sinc interpolation generating phase shift?
I want to simulate the play-rate change function of a modern digital sampler. For the purpose I have constructed a sinc-resampling based algorithm of my own which changes the play-rate of a digital ...
7
votes
1answer
4k views
Python's $\tt resample$ vs $\tt resample\_poly$ vs $\tt decimate$
I have multiple signals each measured with a sampling rate 300Hz. They are mostly periodic, although there are some parts of some of the signals, that seem to be random and do not follow the rest of ...
13
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5answers
10k views
what is better: up- or downsampling?
I want to compare two signals or curves.
Unfortunately they have different sample rates. The first one is sampled at 30 Hz, the second at 2000 Hz. Matlab has the function 'resample' and I thought, ...
3
votes
0answers
7k views
Downsampling and upsampling of a signal in Python
If I want to downsample a signal in Python, is it better to use method resample from SciPy Signal Processing module or method decimate from the same module? What is the difference between these two ...
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0answers
55 views
How to initialize shift registers in polyphase filter based resamplers to avoid or compensate for group delay?
I have a signal a = [a(t0),a(t1),a(t2),..,a(tN-2),a(tN-1)]
I'm using a polyphase filter based resampler with filter length $L$ of $8$, fixed interpolation rate $I$ of $10000$ and decimation rate of $...
2
votes
1answer
252 views
Denoising short, non-uniformly spaced, bandlmited sequences
Consider a bandlimited signal $x(t)$ with bandwidth $BW$. Samples of this signal are observed at non-uniformly spaced sample points in the presence of noise:
$y(t_i)=x(t_i) + n_i \qquad i\in\{0,1,\...
1
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1answer
219 views
Updating FFT algorithm accordingly when upsampling/resampling
I have some experimental data from a shaker (vibration exciter) running at sine $10\textrm{ Hz}$ for test purposes (recorded using an ADXL345 accelerometer with $f_s=512\textrm{ Hz}$. I would like to ...
1
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1answer
138 views
Non-uniform acquisition to fixed sample rate
I'm facing a challenge that requires me to process a signal from an engine knocking sensor. The acquisition is done synchronously with the engine speed (every 0.1 degree) which gives me a range from ...
