Questions tagged [nyquist]
The nyquist tag has no usage guidance.
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1answer
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Amplitude Response at greater than half the sampling frequency
I am hoping to clear up some confusion I have. In a lab I am taking, we analyzed the amplitude response of a simple system. We found that as we increased the input signal frequency to greater than ...
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0answers
23 views
Minimum sample frequency that allows reconstruction of information signal but VIOLATES Nyquist?
Say in the frequency spectrum, you have an information signal between (-100, 100) Hz, and a noise signal between (-700, -500) and between (500, 700) Hz. What is the minimum possible sample frequency ...
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1answer
37 views
Nyquist frequency , sampling distance
I have few questions I tried to solve regarding nyquist theorem, and I would like to see your opinion if I'm doing it correctly?(one I know the answer second one not sure).
1.Let $f(x)$ and $g(x)$ be ...
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2answers
67 views
Nyquist sampling
I know that if $f_\mathrm{m}$ is the "Nyquist frequency" (max frequency) and $f_\mathrm{s}$ sampling rate then $f_\mathrm{s}>2f_\mathrm{m}$.
Am I correct so far?
I have a signal $x(t)$ with max ...
1
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1answer
54 views
Do Nyquist samples have the same sum as the integral of the signal?
Assume I sample a signal according to the Nyquist criterion. Then I perform a simple summation / integral over a linearly interpolated signal. Is this equivalent to the integral over the continuous ...
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0answers
21 views
Why are patterns repeated in the frequency-power graph of a periodic signal?
The original question was posted here.
I have a signal, which I'd like to treat as a non-continuous function now, let it be $signal(t)$. It looks like this:
Zoomed in a bit:
I create a Lomb-Scargle ...
1
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1answer
36 views
Nyquist Rate (Sampling Frequency) for $ {f}^{2} \left( x, y \right) $
We are given that $f(x,y)$ is highest frequency is $\omega$ what will be the frequency sample rate if we want to restore the function of the form $g(x,y)=f^2(x,y)$
Would it be correct to say that ...
2
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2answers
95 views
Why does a higher sampling frequency mess up my bandpass filter?
I was designing a bandpass filter in python using some of the scipy.signal modules.
I am plotting the frequency response of my filter to verify that my desired frequency is in the passband. However, ...
0
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1answer
34 views
Calculate bandwidth of a signal for Nyquist–Shannon sampling theorem
I have to calculate the minimum sampling frequency for the Nyquist–Shannon sampling theorem which is Fc > 2*B, where B is the signal bandwidth.
I have this signals: $\text{sinc}^5(t/2 - 4)$ and $\...
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0answers
41 views
Proving Nyquist Sampling theorem for strictly bandlimited signals
I understand that the Nyquist sampling theorem dictates that the minimum sampling frequency, $f_s$, be s.t. $f_s > 2B$, where $ B $, is the bandwidth of the signal. I have read the explanation for ...
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1answer
43 views
Effective Nyquist frequency / signal resolution for overlapping time averaged signal samples
Say that I have a continuous signal. If I sample the signal at sampling rate f_sample, then the highest signal frequency that I can resolve without worrying about ...
0
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1answer
35 views
What does the frequency band mean when it comes to finding aliases?
The time signal which i'm trying to find the aliases for is:
$$x:{\mathbb R}\rightarrow {\mathbb R}\\\ x(t)=\cos(50t) +2\cos(70t).$$
If the sample period is $T_s = \frac{\pi}{60}$ then according ...
0
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1answer
33 views
Number of discrete samples required for the longest wavelength
I am trying to understand the effect of the critical Nyquist frequency when applying the Goertzel algorithm for estimating the power spectrum of a discrete signal. (Goertzel doesn't really matter, ...
0
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1answer
24 views
Frequency spectra of a sampled process
I have a process $X$ with frequency spectra
I sample this process with sampling frequency $f_s = 2$.
What will the frequency spectra $R_z(f)$ of the sampled process $Z$ look like? I realize that ...
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2answers
71 views
Higher order harmonics during sampling
I am studying about the sampling theorem in conjunction for ADC. I got little confused while reading about aliased frequencies. I see that as per the Nyquist theorem, the sampling frequency (fs) ...
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1answer
76 views
Is it possible to lose half the samples, and yet see the full spectrogram as the original signal?
Consider an speech audio signal sampled at 16,000 samples per second. Plot its spctrogram.
If we delete every other sample from input signal, we get y[n] = x[2n] for all n.
It seems that if we plot ...
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1answer
59 views
Follow up question regarding: “Complex sampling can break Nyquist?”
I'm having some trouble understanding the sample rate limitations when considering a complex baseband signal.
I understand (based on the linked SE questions below), the either (1) physically ...
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1answer
56 views
Minimum Channel Bandwidth for PCM
Please check if my answer to GATE IN 2010 question 11.20 is correct/can be improved upon.
So, every $\frac{1}{f_s}$ sec, a sample is taken. The signal amplitude is quantized into $2^n$ levels such ...
0
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1answer
168 views
Passband vs Baseband Bandwidth
Bandwidth is the difference between the upper and lower frequencies in
a continuous band of frequencies. A key characteristic of bandwidth is
that any band of a given width can carry the same ...
0
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1answer
33 views
Nyquist Stability Test
Currently I'm learning about Nyquist Stability Test and I'm few days stuck on one thing and I don't understand that so I wanted look here for help.
Given is transfer function $K\frac{2s-11}{s(s^2+s+...
0
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1answer
28 views
Nyquist Theorem adding two same frequency near to Nyquist Frequency with phase shift
This is my first question on this platform. Sorry if I made mistakes.
What happens if we add two or more same frequency signals near to Nyquist Frequency with phase shift and sample them?
For ...
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2answers
25 views
Discrepancy in stability conditions when calculating via RH criterion and Nyquist criteria
I have the following open loop transfer function for a unity feedback system.
$$G(s)=\frac{K(s+20)^2}{s^3}$$
1.When using RH criterion it can be easily proved that the closed loop transfer function ...
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4answers
110 views
Nyquist Theorem - Why unique frequencies upto Fs/2 and not Fs? f+Fs is start of Aliasing
If any frequency, f, displays an alias at f + Fs, This shows that unique frequencies have a range of Fs. Why does Nyquist theorem say that actually there is only half of this with unique frequencies ...
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2answers
44 views
Digital Filter Design using difference equations
I am reading a chapter on digital filter design from analog filter design using difference equations. What they do first of all is that they map $s$ (Laplace variable) to $z$ ($z$-transform) by the ...
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1answer
122 views
What is Faster Than Nyquist signaling?
Faster than Nyquist signaling is used to improve the spectral efficiency by reducing the time spacing (relaxing the orthogonality constraint) to pack more data in the same channel while tolerating a ...
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1answer
107 views
Applying Nyquist's sampling theorem to a real signal
I'm struggling to fully understand the Nyquist-Shannon sampling theorem.
For some message input signal $m(t)$ that is infinite in time (i.e. is not identically $0$ for any interval $t_1<t<\...
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2answers
66 views
Is it possible to discretely sample the function
I had a few questions on sampling(I'm quite new witht his), I tried to answer them, I think that I did the first one correct , but not sure about the 2 other:
.
given the next functions,Is it possible ...
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2answers
72 views
How do ADC/DACs deal with out of sync signals near Nyquist frequency?
Let's say a converter is sampling continuously at 48 kHz and the incoming waveform is a sine wave at 24 kHz... How does it faithfully recreate the waveform if the samples are taken at points that are ...
0
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2answers
64 views
Understanding the conditions for recovering a discrete time signal through sampling
So, we had a very brief introduction to the Nyquist-Shannon sampling theorem (the discrete time version).
While discussing this, we have seen that multiplying a discrete time signal $x[n]$ by an ...
1
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1answer
68 views
Distortion of a signal consisting of two periodic components
We have a signal
$$x(t)=U_1\cos\omega_1t+U_2\cos\omega_2t$$
whose frequencies are $f_1=100\,\text{Hz}$ and $f_2=600\,\text{Hz}$. This signal is being discretisated in time using unipolar ...
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1answer
444 views
A voice signal is band-limited to 3.3 kHz. What is the Nyquist frequency?
I'm having a some trouble with an assignment I have to do. I don't come from electrical engineering background and would appreciate any help I can get.
"A voice signal is band-limited to 3.3 kHz. ...
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0answers
33 views
Conditions for representing (perfectly) an analog signal as a digital signal
Consider the following cases:
Sampling with a frequency of the "signal's central frequency"
Sampling a BP signal with twice the frequency of the signal BW.
Sampling an LP signal with the highest ...
2
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2answers
67 views
How to classify filters?
In class, we have defined four types of filters: low-pass, high-pass, band-pass and band-stop. I have understood that in order to classify a filter into one of the fourth, one can use the signals:
DC:...
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1answer
260 views
Stability of open-loop transfer function from its Nyquist plot
I am facing a confusion on understanding system open-loop transfer function stability from its Nyquist plot.
According to the formula, for open loop transfer function stability: $$Z=N+P=0$$
where $N$ ...
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2answers
45 views
Determine minimum sample rate for continuous sinusoid
Consider a signal $$ x(t) = \cos(175\pi t) $$ which is sampled to produce discrete time signal $$ x[n] = x(nT_s) $$ The fundamental period of $x[n]$ is $$ N_0 = 7 $$
Given this, what is the smallest ...
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2answers
185 views
compensation for irregular timestep for FFT
I want to run a clustering algorithm (svm, knn) on the ferquency spectrum data of a temperature sensor that published at irregular times.
Here is the temperature data to take the FFT:
I got the ...
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2answers
79 views
Sampling theory
Imagine I have a 1 kHz sine wave with very low noise. (Assume a signal generator output with 1v peak to peak clean signal). I am using an ADC to sample this signal. Take the following cases:
Sample ...
0
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1answer
105 views
Does the Nyquist Sampling Theorem hold for a triangular wave?
Does the Nyquist Sampling theorem hold for a triangular wave produced by a function generator?
For example, a triangular wave with a frequency of 15 Hz sampled at 60 Hz, 180 Hz and 15000 Hz.
1
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1answer
36 views
Highest frequency of collected force signal [closed]
I have collected force at the footrest during paddling at two occasions. During one occasion I accidently collected the force signals at 150 Hz instead of 1500 Hz. During the other time the data was ...
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2answers
462 views
Minimum possible sampling frequency for continuous time signal
A continuous-time signal $x(t)$ has the magnitude spectrum $\lvert X(F)\rvert$ shown in Figure 6. The signal is sampled to obtain $x(n)$ using the sampling frequency $F_s$. Determine the minimum ...
2
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2answers
822 views
Understanding Nyquist rate
I'm starting to learn signal processing, and am trying to understand Nyquist rate a bit better.
From what I understand, if I sample at a rate > Nyquist rate I'm supposed to have no data loss.
I'm ...
0
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1answer
130 views
Smallest sampling frequency to fully reconstruct a signal
Given the spectrum of analog signal $x_a(t)$ which is imaginary and band-limited, find the lowest sampling frequency to be able to reconstruct $x_a(t)$ from samples $x[n]$.
My attempt: Bandwidth of ...
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2answers
58 views
Sampling below Nyqust Frequency
My understanding of Nyquist's theorem is that you need to sample at a rate that's twice the bandwidth of a signal to fully recover it.
What exactly does the bandwidth mean in this context and what ...
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2answers
173 views
Invertibility of Room Impulse Response: Reproducing Research Paper
I have been trying to reproduce this paper¹. Few things which are unclear to me. The paper talks about finding whether a given Room Impulse Response(RIR) is invertible or not based on Nyquist plot.
...
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1answer
133 views
Lock-In Amplifier Sampling Rate
For a digital lock-in amplifier (synchronous demodulator) I have a sinusoidal reference signal in the range of 10-15kHz, the amplitude and phase I want to observe changes very slowly <10Hz.
My ...
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1answer
60 views
Sub nyquist sampling, required number of samples for time sparse grouped signals
Question: Does it make sense to perform compressed sampling if the non zero samples are grouped in time? If so, what is the minimal length of the vector x that should be acquired to allow full signal ...
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2answers
553 views
Nyquist sampling rate
Please i need help in understanding Nyquist sampling rate. What is the implication of sampling at a lower rate than the Nyquist rate, at exactly the Nyquist rate and at a rate higher than the Nyquist ...
1
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1answer
457 views
Find the nyquist sampling rate?
I have a signal $x(t)$ for which I want to find the Nyquist frequency :
$$ x(t) = \frac{\sin{\pi t/2}}{\pi t/2} \ast \sum^\infty_{n=-\infty}\delta(t-10n)$$
I am trying to solve this in the time ...
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1answer
374 views
How does sampling rate impact Discrete-Time Kalman Filter state space modeling assumptions?
Consider a very simple, discrete-time constant position-type model for state updating in a Kalman filter:
$$
x_{k+1} = x_k + w_k
$$
The Kalman filter will be run with update interval $T_s$ such that ...
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3answers
286 views
Am I violating Nyquist?
I am using a DAC to transmit 2 different voltage levels. High and low. At 1Gsps. There is no carrier wave or anything. These are just raw 0 and 1 time samples going across a wire.
On my ADC I am ...
