Questions tagged [nyquist]
The nyquist tag has no usage guidance.
1
vote
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 ...
1
vote
1answer
53 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 ...
1
vote
2answers
66 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
vote
2answers
408 views
Nyquist frequency and DC
Im studying the DSP book by Steven W. Smith. On page 41 he covers the Nyquist frequency. He makes up an example by writing the following.
... consider an analog signal composed of frequencies ...
0
votes
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 ...
0
votes
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 ...
1
vote
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
votes
2answers
93 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
votes
1answer
33 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 $\...
1
vote
0answers
40 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 ...
0
votes
1answer
41 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 ...
1
vote
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 ...
0
votes
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
votes
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 ...
0
votes
2answers
69 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) ...
1
vote
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 ...
0
votes
1answer
257 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 $N$ ...
0
votes
1answer
27 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 ...
0
votes
1answer
58 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 ...
1
vote
1answer
55 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
votes
1answer
139 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
votes
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+...
1
vote
2answers
24 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 ...
-1
votes
4answers
109 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 ...
-1
votes
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 ...
2
votes
2answers
2k views
Bandwidth with complex sampling
On the transmit side, I have a 20 MHz carrier frequency carrying a signal with bandwidth of 40 MHz (so 0 Hz to 40 MHz, center at 20 MHz).
On the receive side, I have a dual channel ADC with each ...
4
votes
1answer
119 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 ...
4
votes
3answers
1k views
Nyquist plot interpretation when curve hits the origin
I'm a bit confused about the interpretation of the Nyquist plot when the origin is part of the plot. In this case I'm not even considering closed loops, I'm just looking at the Nyquist Plot of a given ...
0
votes
1answer
104 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<\...
0
votes
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 ...
1
vote
2answers
172 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.
...
3
votes
1answer
216 views
Fractional Delay Filters and Cutoff Frequences
I am trying to implement an interpolator for arbitrary sampling rate conversion of a one-dimensional signal (a fractional delay filter). I am aware of the fact that interpolation is in general a ...
1
vote
5answers
763 views
Confusion regarding Nyquist Sampling Theorem
The first time Nyquist Theorem was mentioned in class. It stated that we should sample at twice the highest frequency content of the signal. Example: If we wanted to sample $\cos(2 \pi f_0 t)$, the ...
0
votes
1answer
426 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. ...
59
votes
6answers
24k views
If humans can only hear up to 20 kHz frequency sound, why is music audio sampled at 44.1 kHz?
I read in some places that music is mostly sampled at 44.1 kHz whereas we can only hear up to 20 kHz. Why is it?
0
votes
2answers
71 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
votes
2answers
1k views
Root raised cosine pulse shaping filter
What are disadvantages of root raised cosine pulse shaping filter in digital communications and why does it need to be improved?
Links:
Square Root Raised Cosine Fractionally Delaying Nyquist ...
0
votes
2answers
63 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
vote
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 ...
0
votes
2answers
181 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 ...
0
votes
1answer
3k views
Nyquist criterion for zero isi
I am working with the Nyquist criterion for zero ISI when I find something that makes me think that I misunderstood this criterion.
What Nyquist says is that to avoid ISI in the sampling we must ...
2
votes
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:...
0
votes
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 ...
0
votes
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 ...
-1
votes
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
votes
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.
0
votes
1answer
104 views
Stable gain nyquist plot
From Modern Control Engineering 5th Edition page 469
The transfer function of a plant controller by a proportional controller is given by
$$G(s) = \frac{K(s+0.5)}{s^3 + s^2 + 1}$$
In the book $G(j\...
2
votes
2answers
807 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 ...
1
vote
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 ...
1
vote
2answers
449 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 ...
