# Questions tagged [periodic]

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### Is there any rule of thumb for determining periodicity of a signal just by observation of mathematical expression?

Is there any way(rule of thumb) to determine periodicity of a signal just by observation of mathematical expression as rule of thumb mentioned in attachment for determining time invariance of a system
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1 vote
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### How to calculate frequency of a periodic signal?

I know there are similar topics but I can not find any solution in my situation. I have an accelerometer sensor and a basic microcontroller. Accelerometer data is collected in an array via i2C. I want ...
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### Difference between time period formulas? Continuous time vs discrete time?

For calculating period of continuous time signal,we simply divide 2pi by omega and get period value But in case of discrete time signal, procedure is not straight forward like continuous time, ...
• 1,088
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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 ...
84 views

### How can I check if a signal its periodic from the graph of FFT?

x is a vector of length 1000 that contains the samples of the signal; n is equal to 16 that its the number of bits of each sample; fa=256 Hz (sampling frequency); <...
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### confusions regarding periodicity?

I have a sequence $x[n]=\sin(\pi n+2)+\cos(2n/3 +1)$ I want to find its period and I have also attached my working I have two confusions Is there any effect of the constant term on period? constant&...
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1 vote
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### Change in frequency on differentiation

Is there any possible periodic signal can exist(even mathematically) whose period gets change after differentiation?
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• 571
1 vote
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### How sampling aperiodic signal will result in periodic repetitions of the same

I am reading "Digital Signal Processing" - Proakis and often read that sampling guarantees periodicity (not exact as read) But I wonder how sampling aperiodic signal will result in periodic ...
• 571
1 vote
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### Period of a continuous signal

So I have $$x_1=2 \cos(.6\sqrt\pi x+\pi/6)$$ and $$x_2= \sin(1.2\sqrt\pi x-\pi/3)$$ and need to find the period of $(x_1+x_2)^2$. Let $$a=.6\sqrt\pi x+\pi/6 ~~~\text{and} ~~~ b=1.2\sqrt\pi x-\pi/3$$ ...
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### Why Zero Padding in the Center of the DFT Interpolates / Upsamples the Signal (Sinc Interpolation / DFT Interpolation / Periodic Interpolation)

I'm experimenting with the Inverse Discrete Fourier Transform. Starting from the two-cycles continuous $x(t)$ signal below: I have the discrete signal $x(n) = \{ 1, 0, -1, 0, 1, 0, -1, 0 \}$ leading ...
1 vote
121 views

### Estimate "speed" of repeating signal pattern

I have a digitized signal containing a repeating pattern. One could call it periodic, but the time for one period is not constant. The "speed" with which the period is advanced can change over time. ...
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### Weird resampling artifacts of a periodic signal

I am trying to grab time series data from a database storing data on a propritary format. When i chose a resolution which is not a multiple of the power of two of the sampling resolution i get these ...
4k views

### How can a signal be both periodic and random?

Do any examples of such signals exist where the signal is both periodic and random? Because as I see it, if a signal is periodic then the randomness kinda goes away because you know what the signal ...
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### Fourier transform of a periodic/aperiodic signal

Generally speaking, I know that periodic signals (continuous-time domain signals) with period 2pi/wo have a spectrum with equidistance Delta-impulses of distance w0. My question is that, if we have ...
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### Is $x[n]=(-1)^{n^2}$ periodic?

Is $x[n]=(-1)^{n^2}$ periodic? The answer said no, but when I draw it on a graph, it seems to be periodic, with fundamental period equal to $2$.