Questions tagged [resampling]

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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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18 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 ...
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3answers
338 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 ...
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47 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 ...
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24 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 ...
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95 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. ...
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1answer
137 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 ...
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48 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 ...
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1answer
83 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 ...
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1answer
89 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 ...
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1answer
53 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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80 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 ...
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1answer
192 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]
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1answer
383 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 ...
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1answer
186 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 ...
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0answers
75 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 ...
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52 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 ...
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3answers
61 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/...
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2answers
187 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 sent $150\text{ ms}$ long TTL pulses to a computer recording the voltage data, at the same time as to an LED in the field of view ...
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1answer
309 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 ...
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1answer
124 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: <...
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60 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
150 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 ...
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1answer
257 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 ...
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1answer
559 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 ...
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1answer
2k 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: ...
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64 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 ...
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117 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 ...
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1answer
2k 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 ...
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4answers
7k 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, ...
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0answers
5k 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
50 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 $...
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1answer
182 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,\...
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1answer
195 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 ...
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1answer
117 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 ...
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3answers
2k views

Upsampling - What purpose does the interpolation filter have?

I want to apply some nonlinear processing to a signal, namely: I want to implement a tube emulation which adds warmth/harmonic distortion to a digital audio signal. I am worried about aliasing, so I ...
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0answers
59 views

Compensate for residual resampling error with a quadratic phase vs frequency- possible?

With regards to the answer in this post Is it possible to do deconvolution with two data sets that have different sampling rates? I suggest the possibility of compensating for a residual resampling ...
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1answer
472 views

What happens when I try to resample a speech recording from 8kHz to 16kHz?

I have a question regarding resampling in the context of speech. Given a speech recording sampled at 16kHz, downsampling to 8kHz will basically remove half of the samples (each 16000 samples become ...
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2answers
2k views

Resampling of signal with non uniform sampling frequency

I have a non uniform sampling frequency signal and I have to convert it in a constant sampling frequency. I tried to interpolate it with an Hermite spline interpolation but it make a lot of wrong ...
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1answer
269 views

Uniform sample rate

I have some sensors connected to an Arduino Due. The Arduino sends the buffer of data over the its SerialUSB connection. The last element of this buffer defines when are passed 1 seconds (it is 0 "...
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1answer
239 views

Fractional Delay Filters and Cutoff Frequences

I am trying to implement an interpolator for arbitrary sampling rate conversion of a one-dimensional signal (a fractional delay filter). I am aware of the fact that interpolation is in general a ...
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2answers
241 views

Spline-Based Adaptive Interpolation Filters?

My understanding of interpolation specific to resampling applications is limited to the concept of inserting zeros, then designing a filter to minimize distortion in the passband and reject the images ...
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2answers
308 views

Ripple in time-domain using lanczos resampling

I'm seeing ripple in the time domain when resampling a "unity signal", that is, all ones, with lanczos filters. The ripple/error exactly resembles a cosine with a period of the sampling rate - ie. the ...
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1answer
304 views

Resampling scattered data with MATLAB's $\tt interp$ and $\tt resample$

I am recording acceleration data with an MPU6050 connected to a Arduino1 and stored on a SD. Here you can find the code. I need to calculate the FFT of an acceleration signal that was not sampled ...
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2answers
66 views

Upsampled input to an Adaptive filter?

I will try to explain the issue I am having as clearly as possible without going into my coding or maths. I have my own and a MATLAB Central implementation pf standard LMS in MATLAB. Fixed step size. ...
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1answer
447 views

Is dithering and noise shaping needed when upsampling an audio signal 8 times (from 44.1kHz to 352.8kHz for example)

The main purpose of upsampling before digital to analog conversion is to move quantization noise far beyond the audible spectrum to be able to filter it out by simple second-order low pass analog ...
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1answer
302 views

Does Zero Padding Work as Advertised?

I have trouble accepting the merits of zero padding in the frequency domain to give more points in FFT. Wonder if anyone else has similar thoughts. The mathematical 'proof'for the validity of zero ...
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1answer
212 views

ZOH with polyphase resampler

I'm trying to design a FIR filter(direct form) the coefficient of which will be used to design a polyphase resampler that does Zero-Order Hold resampling. If the direct form impulse response is ...
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2answers
1k views

Resampling an audio signal

I am trying to resample an audio signal in my application. It will be between 48kHz and 96kHz audio (both upsampling and downsampling). Looking at the Wikipedia page for resampling I see there are ...
2
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1answer
194 views

Rate offset and jitter concealment for streaming audio

Given streaming audio samples between two separated devices with separate non-synchronized but almost identical sample rates (say both 44100+-2ppm), what are some methods to best conceal any ...