# Questions tagged [sampling]

In signal processing, sampling is the reduction of a continuous-domain signal to a discrete-domain signal.

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### Stability analysis of hybrid discrete-continuous systems

I'm trying to derive the overall state-space system model for a hybrid system, in order to plot its eigenvalues. The system is shown as follows: Which is originally from this paper: Modeling and ...
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### How does the sample rate work on an SDR?

How can an SDR, which has a sample rate of about 32MHz record signals with a frequency of 1GHz? Shouldn't the sample rate be at least two times as high as the frequency or am i missing something?
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### How to Calculate Frequency "X values" from a FFT/DFT Transformation

First of all I am totally new to the DSP field and I have no background in it whatsoever, but my work in biology has led me to data that would greatly benefit from DSP. Any answers devoid of specific ...
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### Upsampling after S/P convertor in MSK modulation

I have found this post "implementation a S/P conversion: different length / in Matlab" In the given implementation, Tsym = 2*ovs. ...
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### Sampling and Aliasing

What is meant to be explained in the section between the 2nd paragraph and the folding section in the Sampling sinusoidal functions section shown in this link? Why is $Nf_0$ written in $f+Nf_0$ ...
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### Optimum sampling frequency for decoding analog PDM stream?

I have an analog value coded as an analog PDM stream, which has a toggling frequency $f_{PDM} \approx$ 100 kHz when the value is at midscale. I am demodulating this value into a 32 bit result with a ...
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### Given a signal that is not bandlimited, how do you properly take the FFT?

I assume that the Nyquist theorem doesn't apply, at least not in the standard sense, for a non-bandlimited signal. In my case, I sample the signal (in the time domain) above the Nyquist rate and then ...
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### Given the Fourier Transform of a continuous signal how can I sketch the sampled signals discrete time fourier transform

I am given the frequency response for a continuous time signal X(jw) = 2 at w=0 and 0 at w = -10000pi and 10000pi. Looks like a triangle. I am told to sketch X(e^jw) the frequency response of a ...
1 vote
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### How does under sampling modify the spectrum of a signal in nyquist zones and BW?

I have two conflicting concepts when looking at the spectrum of a analog to digital signal that has been sampled. The nyquist zones. So any sampling frequency fs will make the spectrum replicate at ...
1 vote
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### How to convert discrete-time QAM pulses to a continuous-time signal using the IFFT (for OFDM)?

So I've run into some trouble in trying to plot the PSD of an OFDM signal. Specifically, I cant see how we go from the discrete domain to the continuous in time domain. I have a time vector, which is ...
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### Inferring shape of information signal from its DFT?

I came across this question recently, and I am very confused by (b)(ii). b(i) gives $x_n$ = [0.5, 0, -0.5, 0]. My approach to (ii) was to recognise that $X_m$ represents the frequency content of the ...
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### Calculate i. Sampling interval ii. Physical signal length ii)fundamental frequency of s iv. Maximum frequency tv. spatial distance (in mm)

Assume we have a 1D print pattern with a resolution (i.e., spatial sampling frequency) of 120 dots per cm, which equals approximately 300 dots per inch (dpi) and a total signal length of N= 1800 ...
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### Can someone please explain to me how to sample in the time domain?

I am trying to understand how the Nyquist-Shannon theorem applies to sampling in the time domain. Suppose I want to sample a function whose time constants I know. From what I understand, the bandwidth ...
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### What is the Fourier convolution theorem range of application (example of Dirac comb times rectangular window)?

$\DeclareMathOperator{\sinc}{sinc}$ I have questions regarding the Fourier transform of the product of functions or distributions and the range of application of the convolution theorem. Context When ...
1 vote
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### how can 16bit depth look like 10bit?

Recently I obtained some measurements using a consumer grade ECG device (wearable, thus designed for low power consumption). The device is claimed to have a dynamic range of 10 mV (peak to valley), ...
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1 vote
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### Multiplication term $\frac{ 1}{T_s}$ in sampling theorem

$$X(\Omega) = \frac{ 1}{T_s} \sum ^{\infty}_{k=-\infty} X_a\left \lbrace \frac{\Omega /( 2 \pi) - k}{T_s}\right \rbrace$$ What is the purpose of multiplying sampled ...
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### Estimating quantification and sampling error

I have a signal sampled from $\mathbb{R}^2$ at a frequency of $2\text{Hz}$. It is quantized from $\mathbb{R}^2$ to $\mathbb{N}^2$, seemingly using the round operator. How can I estimate the error ...
1 vote
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### Signal flow for conversion of audio to Lzeq (sound pressure level time-equivalent)

I'm developing an embedded system which takes in digital audio from an ICS43432 MEMS-microphone via the I2S-bus to compute the sound pressure level over variable ...
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### Channel impulse response vs sampling frequency

As part of my uni assignment I have to figure out what is the impact of sampling frequency on actual channel impulse response. One obvious thing is that the higher sampling frequency is, the more taps ...
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### Effect of sampling a cont. stochastic process on the variance

I am trying to understand the estimation of the power spectral density of a continuous time stochastic process from it's samples. Consider a normal wide-sense stationary white noise process with ...
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1 vote
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### Will or can a sampled signal with a limited sampling frequency have infinite bandwidth?

I know that a continuous-time digital signal with sharp edges (e.g. jumping from one y-Value to another discontinuously at the same x-value) will have infinite bandwidth. But what about sampled ...
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1 vote
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### Resolution of phase measurement using cross Correlation

The setup is the following: I am using a RedPitaya board to measure the phase shift of two input signals. These input signals will sweep logarithmically from 1kHz to 100 kHz in 10 seconds. Currently, ...
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### does T = 1/F always hold?

i just want to know if i use a sampling frequency of 100-110Hz and get a useful signal frequency of 50Hz (because of Nyquist–Shannon sampling theorem), is the period 1/50Hz or 1/100Hz? I've been told ...
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### Sampling frequency vs Signal frequency

I've started recently working with the ADXL345 accelerometer with the goal of finding the velocity. And so far, I'm getting "okay" results after applying a second-order Butterworth filter to ...
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### How does the RMS value of noise varies with sampling frequency?

I have been trying explore the background rates due to thermal noise (instrumental) through a simulation (python). So, what I have been essentially doing is the following ...
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### Artifacts on frequency spectrum

I made a spectograpm in C that takes in a wav file (44.1kHz), converts it to 8bit pcm(can't go higher because of memory constraints) and does 1024 sample FFT on a number of bins, using Welch method. I ...
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1 vote
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### Digital Up Converion and Digital Down Conversion

Description: I’m trying to use the standard sample rate of 61.44 MSPS on both sides of my digital transceiver(DUC and DDC), so I’ll upsample my data from baseband data rate 3.84 MSPS to 61.44 MSPS ...
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### Reconstructing function from samples

Assuming I have sampled my function with frequency above nyquist frequency, using the sampling theorem I can reconstruct my original function from the sampled values. Let's assume though that I change ...
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### Spectral function value of a frequency above the nyqist limit

this was the question on my today's exam on signals and systems: *We have a continuous function $f(t)$. Its value of the spectral function at an angular frequency of $8000\pi\ rad/s$ is \$\frac{1}{...
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