# Questions tagged [resampling]

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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, ...
23 views

### 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 ...
• 31
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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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### 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 ...
• 121
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### 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 ...
• 101
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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 ...
• 101
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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 ...
46 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 ...
• 101
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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 ...
• 103
83 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 ...
88 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) = ...
43 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 ...
• 103
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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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### 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 ...
365 views

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1 vote
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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 ...
171 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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### 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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### 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 ...
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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512 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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### 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 ...
37 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
148 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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### 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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### Upsampling implementation

I have problem with upsampling implementation in the following way: My code: ...
• 3
475 views

### 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: ...
387 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
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### 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 ...
• 445
322 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 ...
1 vote
150 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
104 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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### 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 ...
• 159
119 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 ...
60 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 ...
• 355
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### 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 ...
• 309
351 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 ...
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### resample interpolation decimation filters algorithm

I'm creating a program in order to perform Resample, Interpolation and Decimation Frequency. ...
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### 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 ...
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### 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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1 vote
716 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
63 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 ...
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### 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 ...
• 173
1k 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 ...
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259 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 ...
• 173
384 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, ...
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1 vote
42 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 ...
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1 vote