# Questions tagged [upsampling]

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### Applying 2D Sinc Interpolation for Upsampling in the Fourier Domain (DFT / FFT)

Related to The Proper Way to Do Sinc Upsampling (DFT Upsampling) for Uniformly Sampled Discrete Signals with Finite Number of Samples, how can one apply Sinc upsampling in the DFT / FFT domain for a ...
1 vote
46 views

### Up-sampling images and the Periodicity of the copies

In the three figures below, $H(e^{j\omega})$, $H(e^{2j\omega})$, and $H(e^{4j\omega})$ are shown. I understand that up-sampling shrinks the spectrum. However, I need a few clarifications: Why does up-...
81 views

### Upsampling of a signal

A low-passed signal, bandwidth limited to 4KHz is originally sampled 10 KHz. If I want to resample it at 20 KHz, I take these steps. Are these correct? Am I missing an step? First we need to filter ...
76 views

### upsample impulse response

I have a system and I know its impulse response $h$, this impulse response was recorded at $f_s = 48000 \texttt{Hz}$, now I can use Matlab to get the system output to an arbitrary signal ($x$) by ...
51 views

187 views

### Efficient Implementation of Digital Upconversion

I have an application where I have a pulse shaped QAM signal, at 2 samples per symbol. I need to take the I/Q samples and perform quadrature upconversion so that they can be output on a DAC that's ...
1k views

### Synchronizing 2 time series signals at slightly different sampling frequencies

I'm working with an embedded system that has two acquisition channels and unfortunately, their clock crystals are slightly out of sync. Even though both boards are configured by software to sample at ...
229 views

### when is downsampling followed by upsampling shift invariant

i have a set of images that i need to send through an hourglass-type convolutional system. I understand convolutions are shift-invariant, so i will ignore them the question is then: If I downsample a ...
251 views

### AWGN noise variance in upsampled BPSK signal

When I simulate BER for basic PSK schemes, I set the IQ complex noise variance to $\sigma^{2} = \frac{E_{s}}{2*R_{m}*R_{c}}*\left( \frac{Eb}{No}\right)^{-1}$ where $E_{s}$ = Energy per modulated ...
1 vote
49 views

### 3D interpolation of a volume with irregular upsampling

Given a collection of 2D slices which as a whole corresponds to a 3D volume (medical image of an organ), I only take specific slices (i.e. I replace the ones I dont want with zeros) and so, I end up ...
204 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 ...
1 vote
239 views

### Should upsampling impact the amplitude of an autocorrelated signal?

I want to autocorrelate a signal using numpy's correlate method. Let us consider a 10 minutes long signal sampled at 2,000SPS: ...
314 views

### How does upsampling/interpolation/oversampling help with noise shaping?

That's all, Why does upsampling improve the resolution and signal-to-noise ratio? What makes it so good for noise-shaping
315 views

### Why symbols have to be upsampling, if the symbol rate and sample rate is same what happen?

In digital modulation process, after constellation mapping and before pulse shaping, the symbols are upsampled with the number L(samples per symbol). At this moment, why symbol have to be upsampled, ...
45 views

### In repeated upsampleing and downsampling by 2, how do i calculate the output Y(z)?

For example, if X(z) -> {downsampled by 2} -> {upsampled by 2} -> Y(z) Given that: X(z) = 1+z^2+z^12+z^19 How do I compute the value of Y(z)?
86 views

### How is non-integer upres downres (1080p game on a 1440p screen etc) calculated

Please redirect me if this is not the right place to ask. I was unable to find a straightforward answer to this question. What I am wondering is, if I am playing a 1080p game on a 1440p display, what ...
1 vote
4k views

### How to correctly use sinc interpolation in Matlab?

What is the right way to use sinc interpolation for a given discrete signal $x[n]$? Following is the sinc interpolation formula: x(t) = \sum_{n=-\infty}^\infty x[n] \mathrm{sinc}\left(\frac{t-nT}{T}\...
137 views

### Perfect reconstruction in two-channel filter bank

[from Discrete-time Signal Processing by Oppenheim and Schafer, 3rd ed.] I was not able to prove this: If the analysis and synthesis filters are ideal so that they exactly split the band 0 ≤ |ω| ≤ π ...
1 vote
154 views

### Book suggestion for upsampling and downsampling

I want to ask for a good textbook or online material which explains in detail: -the time and frequency domain mathematics behind upsampling and downsampling. -easy to follow Note: Oppenheim's ...
5k views

### How can I upsample 22 kHz speech audio recording to 44 kHz, maybe using AI?

I have a 22 kHz mono audio recording, which is mainly speech, a reading. I would like to upsample somehow to 44 kHz, to improve the audible quality. I have read about there are AI methods for ...
How do we show $y_0(n) = y_1(n)$ when $h_k[n] = h[n] \cos(\frac{2\pi}{L} k n )$
The experiment is the following: Given a 1d signal, e.g., a vector of values $f$. Let $F$ be its DFT, i.e., $F=fftshift(fft(f))$, shift is just to have DC centered. Then we upsample $F$ as \$uF=...