# Questions tagged [sampling]

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

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34 views

### ADC sampling rate and signal bandwidth for FHSS

If i am correct; for a radio receiver the ADC sample rate will have to be higher than at least twice the BW of the data (disregarding sparse sampling techniques). So for frequency hopping spread ...
33 views

### Simulating Effects of Sampling after Butterworth Filter

Is there anyway to simulate the effects of sampling an analog signal with Python/MATLAB? I am trying to show what happens to the frequency domain (magnitude and phase) of the analog signal after it ...
121 views

### Minimum sampling frequency, quantization, and bitrate calculation

An analogue sensor has a bandwidth which extends from very low frequencies up to a maximum of 14.5 kHz. Using the Sampling Theorem what is the minimum sampling rate (number of samples per second) ...
61 views

### What is the Uncertainty or error due to sampling frequency?

If I want to detect the distance between two peaks in a signal sampled at 100 Hz. Then is it right to say that the first and second peaks occurred within 0.01 seconds of uncertainty? Therefore, the ...
15 views

### Dynamic sampling points based on the first order derivative of signal amplitude

Problem: I need to measure an arbitrary experimental data set $x(t)$ where t = linspace(min,max,N). However, the experiment is extremely time consuming and I don't ...
37 views

### Relation between continuous time transfer function and sampled approximation

Suppose I have some continuous time system and associated transfer function: $$y(n)=x(n)+x(n-1)$$ $$H(j \omega) = 1+e^{j \omega (-T_s)}$$ Now suppose I create a discrete-time approximation of this ...
66 views

### I/Q sampling with just one ADC

Usually I/Q sampling is performed on two signals with a 90° phase shift using separate ADCs. Suppose I have only a single (fast) ADC available to perform I/Q sampling, which approaches do exist? Is ...
46 views

### What should be IQ sample rate at least?

As i read, IQ sample doesn't need nyquist criteria. What is the mathematical representation of this result? Why IQ sample doesn't need nyquist frequency? I know that can be set to nyquist frequency ...
131 views

### Under what conditions is there a one-to-one mapping between continuous-time and discrete-time signals?

As the sampling theorem dictates that the uniform sampling frequency must be at least twice the maximum frequency present in the bandlimited signal (Nyquist rate), a question arises about the ...
44 views

### How to measure correlation between 1 bit samples and theoretical original waveform?

I'm investigating quantization error. I have an analogue waveform that looks like this and is of theoretically infinite resolution:- I've sampled it as (8 bit oscilloscope readings & 0b1) to ...
110 views

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### Is Sum of Absolute Value / ${L}_{1}$ Norm of Differences Convex?

I'm not sure how to approach this exercise. One idea is to derive it w.r.t z, show that there is a min-extremum at $z=f_k$ and then show that for each value from the right and the left of the loss ...
28 views

### sampling using L1 optimization

As much as I understand the F should be the interval medians (correct me if I wrong), according to the next slide, where is also the Loss function defined: What I don't understand is the next note in ...
120 views

### Why Is the Total Time Equal to $N \cdot {T}_{s}$ and Not $\left( N - 1 \right) \cdot {T}_{s}$ In the Context of DFT?

In the definitions of the DFT DFT $$X(j)=\sum_{k=0}^{N-1} x(k) \exp \left(-i 2 \pi\left(\frac{j}{N}\right) k\right)$$ Let us say, if we have $10$ points, $N=10$, each sampled at $0.2$ seconds, why ...
39 views

### Quantization and Sampling - putting it all together

So after I learned this two topic: quantization and sampling, I'm learning the way to look at both of them and try to optimize the split of a given amount of bit B to N and k, where N is the amount of ...
41 views

### NUFFT of non-uniformly sampled signal

I am trying to understand how to use nufft from the Matlab doc. My goal is to compute a FFT of an image (2D) which has missing points (not sampled). I have a list x and y of coordinates of the points ...
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### The peak in frequency spectrum from sampled data is higher than the true amplitude

I am given a task to do sampling on the function $$f(t) = 1.3 \sin(2\pi \cdot 10 \cdot t)$$ with sampling frequency 4 Hz and start at time t_start = 0.0877s, so ...
51 views

### Relationship between amplitude and sampling rate

I'm loading a signal with librosa in python. With the original sample rate of 22050 Hz, i get the following waveplot: When i choose to resample my signal with the sample rate of 512 Hz, i get the ...
270 views

### How Do I Measure the Time Duration of a Finite Length Discrete Sequence?

Assume I have a five-sample time-domain sequence (none of the five samples are zero valued) and the time period between each pair of samples is one second. Measured in seconds, what is the time ...
22 views

### Response time of residual current device and sampling times

The table below is from this document: Schneider RCD When the maximum response of the device is 40 mS, does it measure current doing RMS or peak detection? The document does not explicitly say it. ...
26 views

### Impulse invariance vs. DT representation of a CT system: Where is the inconsistency?

Suppose you have a continuous-time (CT) system $h_c(t)$, bandlimited to $B$. Your goal is to represent the system as a discrete-time (DT) system $h[n]$, sampled at $f_s \leq 2 B$. Clearly $h[n]$ won't ...
254 views

### What can be meant by “bandlimited”?

This question was a source of disagreement on whether "amplitude aliasing" can occur for a signal bandlimited to below half the sampling frequency. The question was closed before the ...
426 views

### Amplitude modulation vs sampling rate? [closed]

As a sampled tone's frequency nears $f_s / 2$, amplitude modulation grows apparent: ("Actual" curve in grey; blue is what we get if taking samples (dots) "at face value"). This is ...
54 views

### Coherent Sampling vs Windowing for 50/60 applications

Let's say I need to sample 50/60 Hz signals to find RMS. I can use for example 1kHz sampling frequency. That means 100ms sampling is 5 cycles of 50Hz and 6 cycles for 60 Hz. That's coherent sampling. ...
586 views

### Increasing SNR and Dynamic Range using Oversampling

How much gain in dynamic range and SNR can be expected if we are to oversample a signal with fixed analog input bandwidth. For Example if I have a analog filter at the input which limits the bandwidth ...
103 views

### Aliasing at $f_0 + kf_s$

In this question, it has been proved that $x(t) = \sin(2\pi f_0 t)$ and $x_k(t) = \sin(2\pi (f_0 + k f_s) t)$ have the same sample points. So sinusoids with frequencies $f_0$ and $f_0 + kf_s$ will ...
39 views

### Sampling frequency error in OFDM [duplicate]

If the sampling rates at receiver and at transmitter are different, there will be ICI. However I don't find any practical technique to estimate and compensate this kind of error. Is it true that we ...
64 views

### Inverting a sampled system

I'm doing some self-study for an upcoming exam and came across the following question: My first idea to solve it was using the bilinear transform to get some approximation of $H(Z)$ (or just using ...
19 views

### fo we need RMS in SNDR of harmonic distortion

In my system we have the following. $$V_{in}=1+\cos(2\pi 900,000)$$ $$V_{sample}=V_{in}-0.01V_{in}^2$$ $$V_{noise}=200 \times 10^{-6}V$$ After the input i get in $V_{sample}$ the following ...
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### why we do multiple aliasing of high order harmonics

the general rule for aliasing. If my sampling frequency is Fs=800Mhz signal frequency =120Mhz. for the 4th harmonics 480MHz its 80MHz above nyquist frequency(400Mhz) thus its mirrored 80MhZ back to ...
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### Goertzel filter for non-equidistant sampling

We have a sensor that reports a new value asynchronously only when the value changes. Therefore, we receive samples at arbitrary time stamps. We basically receive value + timestamp of the measurement ...
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### Why negative harmonics copies in sampling

i have a signal of 120Mhz and sampling at 800Mhz. we look at the region of fs/2=400MHz so obvios we have harmonics of the fundamental which is 240 360. But in the document i see that there is another ...
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### Multiplying signals in discrete-time vs continuous-time

Given two discrete-time signals $a[n]$, $b[n]$ and its product $c[n]=a[n] b[n]$. The ideally interpolated, continuous-time version of $c[n]$ is \begin{align} c_1(t)&=\sum_{n=-\infty}^{\infty} a[n] ...
73 views

### Sampling Dirac function and a DC signal

Can we sample the Dirac function? $$x(t) = \delta(t)$$ Can we sample a DC signal? $$x(t) = 1$$ I think that we can't sample $x(t) = 1$ because the Fourier Transform of $x(t) = 1$ is \$2\pi \delta(...
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### Downsampling vs. ADC with lower Sample-Rate

I would like to know in general where the advantages and disadvantages are: Downsampling of a high sampled continuous analog signal in FPGA or µC and Direct use of a lower sampling rate, i.e. using ...