Questions tagged [sampling]
In signal processing, sampling is the reduction of a continuous-domain signal to a discrete-domain signal.
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Resolution after Oversampling, Filtering-Decimation
The ADC I am working on has a resolution of 24 bits and a Signal-to-Noise and Distortion (SINAD) of 108.4 dB. Assuming only quantization noise is present, the Signal-to-Noise Ratio (SNR) of the ADC ...
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How is the normalized power required for unipolar NRZ twice that of polar NRZ?
So, the normalized power for unipolar NRZ scheme is $\frac{1}{2}V^2$. According to my book, the normalized power required for polar NRZ is half that of unipolar NRZ. So, the power should be $\frac{V^2}...
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Plot amplitude vs freqency in DB
I have C++ App which wich plot 3 plot
amplituede vs sample
amplitude vs frequncey(used FFT for calculation)
amplitude(in dB) vs frequncey
I want plot 2 with y axis lable represent in DB, without ...
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Estimating spectrum with regularly missing samples from data
Suppose:
$$
s(t) = \sin(2\pi{f_0}t)
$$
Suppose I'm sampling the signal with a sample frequency $f_s >2f_0$ .
However, every $M$ samples there is a dead-time of $L$ samples.
Traditionally, the (...
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How can I plot a sinc function correctly?
I am generating a rectangular pulse using a piecewise function on Matlab. I have listened to some advice to use a normalization coefficient and the amplitude appears correct now. However, my issue is ...
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Is there a test/statistic for the reliability of my data given my sampling?
I'm in a situation where I'm sampling blood pressure data over time (unequal sampling) to capture potential peaks. On average, the frequency of circadian blood pressure would be 1. But in reality, ...
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Anomaly in Magnitude Spectrum plot of an ASK Signal
Following is a SciLab code and Plots for Modulation of ASK Signal:
My question is :
For these particular values of fm and t, I get two weird small spikes on either side of main lobe, which doesn't ...
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DAC sampling rate when using DSSS/CDMA
I'm currently not sure if I understood DSSS correctly.
Following example:
We have a shared RF network with around a thousand of users and we want to use CDMA. The RF link should allow the streaming of ...
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When converting real samples to complex, how much energy does the signal lose?
Assertion: When converting real samples to complex, the resulting complex vector will have half the energy of the original real vector. Simulation in Python tells me this is true. However, my proof ...
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Partially undersampling effect on FFT
I am struggling to understand the effects that partially undersampling a signal would have on its FFT. I have a complex signal consisting on a sum of sinusoids of different frequencies, which I am ...
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How does aliasing affect bits in an ADC?
I want to measure a signal whose frequency spectrum is infinite, but I am particularly interested in the frequency range $ 0 - 500 \ \text{Hz}$.
I have a 12-bit ADC. The ADC has dynamic range $ 6 \ \...
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Bilinear transformation with a high sampling rate (chebyshev filter)
I'm trying to design a digital Chebyshev filter of order 2. This gives the general transfer function
If I transform this and simplify I get
If I then expand the denominator and then normalize so ...
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Combining two time series with different cadences (different Nyquist frequencies)...?
If it helps, I want to do perform the below computation in python.
Two time-series - 30-min cadence (Nyquist of 24 cycles / day) lasting 27 days, followed by 10-min cadence (Nyquist of 72 cycles / day)...
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How to minimize RMS calculation error due to sampling?
Say I have a sinusoidal signal of 49.93 Hz, which is sampled at 16 kHz. A period of the input signal would then contain 16000/49.93 = 320.448 samples. Naturally, the number of samples has to be an ...
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Sampling a sinusoidal signal smaller than Nyquist rate
If we have a sinusoidal signal at 50 kHz and we sample it by an ADC with a sampling rate of 7 kHz. What would be the output of the ADC?
Since the sampling rate is way less than the Nyquist rate (...
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Why am I getting 2 frequency spikes in a mono tone signal?
I have a single tone sinusoid, and its fft in scilab is giving me double spikes, why is that?
Please explain me the concept of why is it happening.
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How does downsampling decrease the noise power?
I read one equation from a technical document, i.e., assuming the time-domain white Gaussian noise samples with variance $\sigma_{TD}^{2}$ in dB are sampled using ADC with sampling rate $f_{s}^{ADC}$, ...
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Noise variance of DT samples from CT track-and-hold signal
(I will be referring to info from these slides in this post, for your reference.)
Consider first for comparison a typical CT low-pass filter, without any sampling, for example implemented by the RC ...
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Symbols to samples at the transmitter and samples to symbols at the receiver
Suppose I have the $N\times 1$ vector $\mathbf{x}$ that contains binary phase shift keying (BPSK) symbols each with power $P_s$ Watts.
At the transmitter: I want to convert these symbols into samples ...
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Sample rate change using Lagrange interpolator
I'm trying to understand how to make Sample rate change by a non integer factor say $K=1.0012$
In real hardware I will be using cubic polynomial but for now I have chosen a linear interpolator. I have ...
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producing sine signal with few samples
I need to produce a signal of $\sin(2\pi\cdot 60\cdot10^6 t)$, where $t$ in sec, with sample rate of $2^{28}$ Hz.
Since the signal has period of $\frac{1}{60\cdot 10^6}$ sec can I somehow sample only ...
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Sampling a pulse train with a controllable square wave
I have an issue regarding a sampling process of a pulse train in an image sensor based on events. Basically, these are a family of image sensors in which each pixel outputs a train of pulses, and the ...
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Choice of $N_{terms}$, frequency grid in Lomb-Scargle periodogram
I am completely new to signal processing! Please explain as if speaking to someone who knows nothing more than linear algebra and what a Fourier transform is defined as.
I am working with an 8-month ...
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Decoding an analogue signal for a given sampling and signal frequency that aren't in sync
I am trying to decode an analogue signal, that is intended to be converted to a digital one and decoded as USART communication.
In the image shown the blue trace is the analogue signal, and the ...
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Understanding Sampling Frequency
I am new to signal processing and I am unable to understand the concept of sampling frequency. This YouTube video presents 20Hz to ...
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Find constants such that the Nyquist criterion is satisfied [closed]
I have been given the following spectrum, and I want to find a and b such the pulse satisfies the Nyquist criterion, given that the bandwidth of the pulse is 2 kHz and the sampling frequency is 3 kHz. ...
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Build a shifted signal samples from the original samples
I have the original samples $\{x_1(nT)\}_{n=1}^N$ of a signal $x_1(t)$, where $T=\frac1{f_\mathrm{s}}$ is the sampling period. I want to find the samples $\{x_2(nT)\}_{n=1}^N$ of the signal $x_2(t)=...
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Handling asynchronous MCU I/O peripherals
Technical Background
I'm making an audio processing board with an onboard microcontroller that takes in data via I2S from an ADC, applies digital filters, and outputs a stream of the same samplerate ...
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Sampling a QPSK signal in Simulink, changing the bit rate and sample rate
my goal is to sample a signal that I generate in Simulink and do some "real time" DSP. I want to try implement some signal classification techniques I have been learning.
I tried to make a ...
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How to approach signal reconstruction with sampling frequency not equal to reconstruction
I'm trying to figure out what kind of equations i can use in a situation like this:
I know the relation between $x(t)$ and $x[n]$ is :
but then $x[n]$ is multiplied by a pulse train, with a ...
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Does SDR configured with low sample rate automatically averages samples?
This is probably a basic question but I didn't find any answer online.
Suppose we configure a SDR (least say, with a maximum sample rate of 100 Msamples/s) with a low sample rate (e.g. 1 Msample/s).
...
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Effect of sampling rate and duration on discrete parameters of sine (spectrum)?
The DFT of
$$
\cos(2\pi f t + \phi)
$$
peaks at $k=\pm f$ if $t = \frac{1}{N}[0, 1, ..., N - 1]$ (for integer $f$, & within Nyquist). What about other $t$? What if we double the sampling rate or ...
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How to represent nonuniform resampling of signal using math functions?
I am working on optical coherence tomography algorithm. In main pipeline I should use nonuniform resampling to eliminate transformation of optical signal in IR-spectrometer (that signal disperses by ...
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Why does the white noise of a signal diminishes as sampling frequency increases?
I'm trying to understand how oversampling can help to reduce the signal to noise ratio, so I looked this document, and at page 6 it is said that:
Along with the input signal, there will be a noise ...
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Examples of digital signals occurring in Nature
In Chapter 1 of Oppenheim & Schafer's Digital Signal Processing, the authors state that not all discrete-time signals are the result of sampling continuous-time signals, and thus they are making ...
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Correlating signals in real-time when the time-delay is larger than frame-time
What are some possible approaches to address the challenge of correlating two signals when the time delay ($T_d$) from the source to the microphone is greater than the microphone's frame time ($T_f$)? ...
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Laplace domain transfer function from system sampled at discrete times
I'm trying to understand an analysis of a sampled continuous time system in the Laplace domain. The source analysis is here (PDF page 6, slide marked 11); I'll explain further below. Suppose I have a ...
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How to understand "independent sample rate" of windows?
A window metric called independent sample rate is given in a book that I recently read. It says that in spectral estimation, the variance of power-level estimates is inversely proportional to the ...
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Filter choice for the signal with the possible time jitter in sampling and frequency aliasing
I'm trying to filter data from the force sensor mounted on the end effector of the industrial robot arm. Mechanical vibration caused by the robot's motion (possibly by actuators, reductors, etc.) ...
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Sampling frequencies calculated on paper and in MATLAB not matching
So, I've been working on a signal described by the equation $$y(t) = \cos(2\pi \ |sin(2\pi t)|).$$ On paper, I've calculated a sampling frequency of at least 2 cycles/sec, since the frequency of my ...
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What is the minimum sampling frequency to reconstruct a 1 Hz sine signal by using only FOH?
Consider a signal $s(t) = \sin(2\pi ft)$ where $f = 1$.
Let's now discretise it by replacing $t$ with a vector of $n$ sampling instants equi-spaced by a sampling interval $T_s = \frac{1}{201}$ s, thus ...
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Is downsampling LTI for bandlimited inputs?
This question stems from the discussion we had on a previous question of mine.
The point of contention is whether the downsampling operator is time invariant or not. Which gives us a new condition to ...
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Can time aliasing cause peaks?
For the following I use the terms “time domain signal” and “frequency domain signal” as a Fourier Transform pair. The question is for generalized cases of continuous-time signals that once sampled in ...
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Minimum sampling rate to detect rising edges in PWM
I have a 20Hz PWM signal (0 - 5V) with a duty cycle of 30%. What would be the minimum/recommended sample rate to count all rising edges in this signal? I'm unsure because Nyquist does not really work ...
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Sampling Frequency of a Rotational Sensor
In the picture above you can see a sensor I've been dealing with, called a "Caliper". This sensor arm simply passes over the pits or bumps on a disk rotating with a constant angular velocity ...
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How to find sampling frequency in aperiodic signal?
I have a signal that is $x(t)=e^{-3/t^2}+2\cos(3\pi t^3)$ and I'm trying to find its proper value for fs. But I couldn't find a way on how to do it. I'm working on an interval $0<=t<=2$ and $x(t)...
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Parallel processing of FIR filter multiple samples per clock cycle
I have an FPGA that is limited in clock frequency, but receives data from a higher sample rate ADC by receiving N samples per clock cycle (all N samples are from a single ADC channel). So the FPGA has ...
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Measuring amplitude of a pure sine wave of known frequency close to the noise floor
What I want to ask you comes from a place where I can play with all the parameters as much as I want (I can measure as long as I want and as fast as I want, as well as change sensor/ADC).
The signal ...
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Is this how to show decimation in the frequency domain?
Let's say I have a discrete-time signal $y[n]$ that is passed through an Ideal Lowpass Filter (impulse response $h[n]$) to get $y_1[n]$. The filter has cutoff frequencies at $\pm \pi/N$ rad.
Now this $...
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Why is implementing a digital LPF with low cutoff frequency but high sampling frequency infeasible?
I am new to signal processing and I want to implement an LPF using SciPy. In order to do so, I used the following python code from: here
The code itself looks like:
...
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