Questions tagged [resampling]

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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?
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Python Resampling: Are there any methods that associate higher frequency with lower frequency? [closed]

Associate higher frequency periods with the lower frequency periods in which they end. When data are distributed, values are assigned only to the higher frequency periods that end in the lower ...
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3 votes
1 answer
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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 ...
1 vote
2 answers
77 views

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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3 votes
2 answers
152 views

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 ...
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1 answer
47 views

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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0 answers
17 views

How to apply a filter that prevents aliasing when reindexing a dataframe to a new datatime index

I have two dataframe and I want to reindex the second dataframe to the index of the first dataframe by downsampling it. This however creates alliasing and as a result an artificial flattening of the ...
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2 votes
1 answer
265 views

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 ...
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0 answers
51 views

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
152 views

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 ...
2 votes
2 answers
55 views

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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Frequency repartition and transformation in channelizer and synthesizer

I am trying to get my head around channelizers and synthesis filterbanks. I stumbled across this thread, with its attached paper. In the explanation of the synthesis filter bank, the following ...
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1 answer
43 views

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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Particle Filter estimation: sinusoidal signal

I am designing a particle filter for the extraction of a sinusoidal wave with known frequency and sampling frequency from Gaussian noised biased measurements ($y=x+\text{bias}+\text{Noise}$) My state ...
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5 votes
1 answer
80 views

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 ...
2 votes
1 answer
49 views

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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1 vote
2 answers
309 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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1 answer
110 views

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 answers
33 views

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 ...
0 votes
1 answer
80 views

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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1 answer
334 views

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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0 votes
1 answer
135 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
117 views

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) = ...
0 votes
3 answers
45 views

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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1 answer
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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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-1 votes
1 answer
299 views

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 ...
0 votes
1 answer
711 views

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; $...
0 votes
1 answer
247 views

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)-...
1 vote
1 answer
140 views

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 ...
0 votes
1 answer
269 views

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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0 votes
2 answers
61 views

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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0 votes
1 answer
575 views

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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0 answers
1k views

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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2 votes
1 answer
766 views

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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1 answer
43 views

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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0 answers
41 views

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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1 vote
1 answer
193 views

Oversampling a signal

I’ve built a circuit with an analogue sensor (70 Hz bandwidth) connected to a 24 bit ADC, which is oversampling the signal at 10 kHz. Nyquist sampling theorem implies I should sample by at least 140 ...
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0 answers
46 views

Resampling assessment

I'm trying to figure out which of the resampling methods is best in my job. Comparing the original image vs. bilinear, bicubic, bicubic spline, lanczos. For now I have considered metrics like MSE RME ...
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0 votes
1 answer
237 views

Upsampling implementation

I have problem with upsampling implementation in the following way: My code: ...
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1 answer
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Upsampling in Python

I'm trying to perform upsampling in Python. Given the signal 's' and factor of upsampling N, I wrote the following code: ...
2 votes
2 answers
519 views

Does resampling cause phase shifts?

I have a signal sampled at 40MHz, I would like to resample it to 37MHz. The signal is not periodic, I did resampling with Matalb resample function and it doesn't cause phase shift (as far as I ...
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1 vote
1 answer
76 views

How to correct for delays in a PAM-X signal with orthogonal CDMA?

I have a receiver which receives data bits at a rate of 5kbit/s. The number of data bits per burst is low (say, 16 bits). These databits are obtained after despreading the incoming signal using an ...
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0 votes
2 answers
434 views

Downsampling issues

I have this data that need to be downsampled so that it can be fed into a classifier. The issue is that I need to downsample from 1000Hz into 20Hz. If you see the graph below, the blue line is the ...
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1 vote
2 answers
172 views

Fourier Transform of sampled reflectance measurements

Goal: Calculate the complex index of refraction ($\hat n = n +jk)$ from reflectance measurements. Data: Reflectance measurements for various materials were taken with a FTIR (Nicolet™ iS50 FTIR, ...
1 vote
2 answers
129 views

Rectify signal basic question

When rectifying a signal by squaring it, is it necessary to upsample by a factor of 2? Why is this?
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1 answer
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Upsampling question- Aliasing/imaging problem

I'm trying to study vibrations in a non-stationary shaft by upsampling the original signal. The original sample rate is at 25.6kHz, and it is being upsampled to 36kHz. In the FFT of the upsampled ...
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0 votes
3 answers
122 views

Interpretation of sample rate

I'm a little confused about the sample rate: If I have an audio file that was recorded with a sample rate of 48kHz, this means that there are 48,000 values per second in this file, right? So when I ...
0 votes
1 answer
67 views

Obtaining a high sample rate digital approximation to an analog filter from lower frequency measurements

Consider a set of dense, but generally irregularly-spaced frequency response measurements of some real low-pass analog filter. Denote the maximum frequency for which a frequency response measurement ...
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0 votes
2 answers
77 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 $$...
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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 ...