# Questions tagged [discrete-signals]

A discrete signal or discrete-time signal is a time series consisting of a sequence of quantities.

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### Does Circular Convolution correspond to Periodically Expanded Linear Convolution?

I have a question whether circular convolution and periodically expanded linear convolution corresponds in following case or why it does not? Think about a signal $x[t]$ and a signal $y[t]$ both of ...
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### MIMO multipath delay [duplicate]

How is multi-path delay dealt with in MIMO systems? Most of the theory I have read on MIMO doesn't address multipath delay and assumes the multipath interference is limited to secondary antenna ...
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### Flicker Frequency for taking snapshot of monitor [closed]

When a snapshot of a monitor with refresh rate 60 Hz is taken with a camera with rolling shutter config operating at 30 FPS, what is the expected flicker frequency in the resultant image? I took ...
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### Window functions and the Fourier transform

I want to clarify the 'correct' way to use windowing and Fourier transforms. My question is somewhat related to this one, but I have a few additional queries. I have some real, non periodic signal ...
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### How to add a particular noise on a signal?

I have a simple ADC model (an input signal == sampled signal ). The adc should be modelled as with following values: 1.5 V (peak to peak).. meaning --> +1.5 V --> 0 dBFS ... how to do this ? The ...
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### Oscillations in a first-order discrete-time linear systems

According to my understanding, continuous first order systems do not exhibit oscillatory behavior because a first order system has only one energy storage element and thus oscillation is not possible. ...
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### Phase Difference offset when measuring phase difference between different FFT bins

In application where two sensors are used to calculate the phase difference of the incoming signal, what is the the phase difference offset which should be added when taking phase difference from ...
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### Hand implementation of Fourier transform have small peaks unseen in Python package

I've implemented the basic version of discrete Fourier Transform and I'm testing it using a pure sinusoid. However, small bumps show up in addition to the large peak. I tried Numpy.fft for this and I ...
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### Wireless Channel Multiplicative Model

Let's assume a SISO channel in the equivalent baseband, the standard channel model (discrete) is: \begin{align} y(k) = h(k)x(k) + z(k) \tag1 \end{align} Where $y(k)$ is the detected signal, $h(k)$ ...
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### Smoothing a discrete function with point wise variances

In Stark's Introduction to numerical methods  it suggests fitting local polynomials to smooth discrete data before the Fourier transform using least squares minimisation. This gives the ...
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### Linearity and time-shifting of $\mathcal{F}\{0.8^n\cos(0.1πn)u[n]\}$

To preface, this is not a homework related question but purely for self-study purposes. Hi there, I try to calculate $\mathcal{F}\{0.8^n\cos(0.1πn)u[n]\}$ by using the properties of Discrete time ...
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### Total Harmonic Distortion THD for the rectifier

I have a circuit with rectifier and this cause the non-linearity and consequently harmonic. I show it on the oscilloscope and then collect the signal from the oscilloscope to the computer by using the ...
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### Difference between Cepstrum and Spectral Envelope

I have no background in Signal processing and i don't understand the difference between cepstrum and spectral envelope. IDFT of the log magnitude of the DFT of a signal is cepstrum then what is ...
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### How to draw a finite-duration sequence

On page $359$ of the 2nd edition of the book "Signals & Systems", by Oppenheim and Willsky, the authors wrote the following words: "Consider a general sequence $x[n]$ that is of finite duration. ...
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### How can we do exact simulation for digital systems? [closed]

In digital control system, there are two basic techniques for finding the best digital controller. First, called the discrete equivalent, we find the continuous compensation and then discretize (best ...
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### convolution expression h(n,k) = h(n-k)

As a new to DSP concepts want to understand the meaning of impulse response and why we do $h(n-k)$ in convolution and $h(n+k)$ in correlation.
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### Why is DTFT of $e^{jn\omega_0}$ an impulse train?

update : After asking the question, I figured out that DTFT result is an impulse train. Now my question evolved to, how it is derived in this way? Using the DTFT formula seems not to be working, ...
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### FFT Phase interpretation of input signal with non-integer number of cycles in FFT window

It is known that if we take the FFT of a signal at such a frequency which has non-integer number of cycles in the sample window we get different value of phase even if the original signal was at phase ...
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### Phase difference between signals sampled at different frequencies

I want to know that if it is possible to measure the relative phase difference between a signal that has been sampled at two different locations with different sampling frequencies? Also can that ...
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### Impulse response of a system in z domain

The question 3-23 in the "Discrete-Time Signal Processing - Second Edition" is: and the solution is: I cannot understand the solution. In the second row of the answer when I multiply (-4) with ...
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### What did I do wrong with this simple filter build?

I tried to put everything I have learned from people here together to code my first filter from scratch. Unfortunately, it didn't go well and I'm not getting the expected output. The math/code became ...
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### Calculating average power of a discrete random signal with complex values

I have a Rayleigh channel that transmits discrete values according to the following: $$y(n) = h(n) * s_n + \omega_n$$ Where $y$ is the received message, $s_n$ is the symbol sent (constellation 2-PSM), ...
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### Proving for windowing function

Prove that $1+2\cos(\omega)$ is the same as $\frac{\sin(\frac{3\omega}{2})}{\sin(\frac{\omega}{2})}$ Knowing that $$p[n]=\sum_{k=-1}^1 {\delta[n-k]}=\delta[n-1]+\delta[n]+\delta[n+1]$$ Doing the FT ...
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### What is the difference between SFO (sampling frequency offset) and SCO (Sampling clock offset)?

What is the difference between SFO (sampling frequency offset) and SCO (Sampling clock offset)? I think they are essentially the same phenomenon?
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### Discrete signal - fourier transform coefficient period [closed]

if I have an example signal in the picture, how can i decide its period?
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### Confused about filter's cutoff frequency in rational sampling rate converter

A interpolator which increase sampling rate by L times is followed by an anti-imaging filter, the filter is said to have a cutoff frequency of Fs/2L. Is Fs here is the frequency before or after ...
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### Applying Wavelet on energy disaggregation as denoising technique to remove uncertainties

I would like to apply Wavelet in MATLAB as a denoising technique on Non-Intrusive load Monitoring data. The data was captured by sensors on each appliance and one sensor on the smart meter (Normally ...
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### Deep Learning based NDA Channel Estimation

I was wondering if it is possible to use Deep Learning to estimate the Channel Impulse Response for NDA synchronization? I understand Deep Learning is not normally used for regression problems but I ...
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### How to Emulate Sample Frequency Offset for OFDM in Matlab?

I am studying the effect of sampling frequency offset on OFDM, and in order to emulate SFO, I have to slightly change the sampling rate of the signal. In order to have a +5ppm offset, I have to change ...
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### FSK carrier frequency estimation

In the MPSK Modulations, Cyclic Spectrum Density method can give a peaks, for example for the QPSK: But in the FSK signal, this peaks do'nt appear. How to solve it?
I already have the value of Image Rejection Ratio (IRR) in dB for IQ imbalanced modulator and I want to simulate this effect using MatLab. How can I obtain $\alpha$ and $\theta$ to calculate the ...