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

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Aperiodic discrete signals

What is the fourier transform for finite aperiodic discrete signals and for infinite aperiodic discrete signals? Are they different?
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18 views

Google's self-driving car and LIDAR interference

Firstly: I hope this isn't the wrong place to ask. I'm usually over in the coding forums. But this seemed like the appropriate forum for the question. It occurred to me that if several of Google's ...
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1answer
26 views

Find the fourier transform of g(k) from G(Z) for frequency=1/2

$$G(z)=\displaystyle \frac{\frac{1}{z}}{1+\frac{5}{6z}+\frac{1}{6}z^{-2}}$$ I found: $$g(k)=\displaystyle \left(\frac{-1}{3}\right)^k - \left(\frac{-1}{2}\right)^k$$ I don't understand how can i ...
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2answers
47 views

Finding fourier transform of a discrete signal from the z transform

Is it possible to find the fourier transform of a discrete signal if you know the $\mathcal{Z}$-transform of it?
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24 views

What is the ROC for this discrete signal:

$$ x(k)=4[u(k-2)-u(k)*δ(k-3)]$$ I found that the $\mathcal{Z}$ transform of the signal is $X(z)=4/(z^2)$. What would the ROC be?
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59 views

What is the impulse response of the system with this difference equation:

The difference equation is written: $$y(k)-\frac{5}{12}y(k-1)+\frac{1}{24}y(k-2)=x(k)-\frac{1}{2}x(k-1) $$ The system is linear, invariant and causal. For $x(k)=δ(k)$, the equation will be: ...
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2answers
58 views

Fourier transform of a discrete periodic signal

The given sequence $$x[k]=\delta[k-1]-3 \delta[k] + \delta[k-2]$$ represents a period of some discrete periodic signal $e[k]$ with period N=3. Find the Fourier transform of $e[k]$. This is an ...
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45 views

Real world dsp implementations examples?

Well,this may be basic, but i find you as the best option to answer this. I am electrical engineer and i have taken dsp courses. There is some algorithm that i am trying to implement on audio signal ...
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1answer
41 views

FIR filter design for response inside unit circle

I would like to design an FIR filter such that its Z-transform has a certain profile in certain regions. For example, if I'd like to have an FIR filter that nulls the decaying exponential ...
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0answers
24 views

DFT calculation for different sampling Frequency [on hold]

while representing a sinusoidal signal in DFT, we will be knowing the Sampling frequency. for example let input signal frequency is 50Hz, and sampling rate is 16, then sampling freq is 800 suppose ...
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0answers
26 views

Why doesn't the mel-scale use the twelth-root of 2 instead of a biased sample listener?

For the mel frequency spectrum, which is used extensively in audio-processing, the technique uses subjects to identify pitches of uniform distance from one another. Isn't this distance just the 12-th ...
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0answers
14 views

How to deal with Imaginary Value of Fast Discrete Curvelet Coefficient?

I want to classify the mean, energy, std, and entropy of discrete curvelet coefficients(wrapping) with Neural Net. But Neural Net can't deal with imaginary value. I have 2 option, either make it real ...
2
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1answer
46 views

Frequency response of a rolling linear regression

I am looking for a way to characterise the frequency response of the slope from a linear regression. We are exploring the effect of window length of the regression to the magnitude of the slope of the ...
2
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1answer
44 views

Per Window Normalization

I have PPG signal that should be normalized, with offline processing I'd just do $z$-normalization, $$ \displaystyle \frac{x- \mu_x}{\sigma_x} \quad \text{where } x \text{ is the signal.} $$ The ...
2
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1answer
30 views

How do DAWs align the phase when working with plugins?

I'm no signal processing guru, so I'm looking for a pretty basic explanation that I'll understand. I've seen this question about Phase Locked Loops, but I have a hard time understanding that, ...
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1answer
36 views

BIBO stability and input at system's pole

My understanding of BIBO stability is that if a bounded input is applied to a discrete-time, linear, time-invariant BIBO system, the output will also be bounded. A sufficient condition for this is ...
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0answers
4 views

SIFT: Finding unstable and stable intervals in interval tree

I try to understand SIFT. I have watched a couple of videos but still cannot catch the point that how we can mark an interval 'unstable'. What is exactly the definition of 'stable'? According to ...
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3answers
81 views

detrending in real time

I have a certain signal that has a linear trend that should be removed. The problem is that the signal needs to be processed in real time(sampling rate is 20Hz). If I only apply the detrending per ...
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2answers
50 views

how to match 2 signals that have same information, though shifted and scaled

I have 2 signals S1 and S2 that contain the same information, but S2 is shifted and scaled compared to S1 by an unknown amount (but small; eg shift would be of the order of 1-10 samples). What is the ...
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0answers
12 views

How to take IFFT of Connes Window?

The Connes Window function is defined as : w(f)=$(1-(\frac{f}{ \Delta f})^2)^2$ for $f<|\Delta f| $ w(f)=0 otherwise The inverse fourier transform of this function can be ...
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16 views

Change of group delay scale in matlab

I have a question concerning the conversion of a matlab plot group delay scale. The book Digital Filters for Everyone, 3rd edition, by Rusty Allred has a matlab plot of group delay in samples vs. ...
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0answers
13 views

How accurate is Wavelet packet decomposition for emg signals with frequencies from 10 to 40 Hz?

I have an electromyographic signal sampled at a frequency between 10 and 40 Hz in a time window of 300ms. Is wavelet packet decomposition adequate in order to perform features extraction for ...
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2answers
71 views

Output of a discrete-time LTI system different form than input?

This question is related to this one. I'm going through old exams for a 2nd year systems and transforms course, and came across this question. I'm posting this question just in case my other question ...
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3answers
58 views

Output of discrete-time LTI system guaranteed to be same form as input?

I know that in the continuous-time context, if I supply a complex exponential input to a Linear Time Invariant system, the output will be of the same form as the input - for example, if the input is ...
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20 views

Figuring out Signal to Noise Ratio of Spectral data?

I have some Raman spectral data of a chemical: Each spectrum consist of multiple tuples of (wavenumber, intensity) I have multiple instances of 1. taken with ...
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274 views

C implementation of LP filter

I have the following code, which I am told is a low-pass Butterworth filter. How do I derive the frequency response and phase for this? I only have experience in analog electronics and so cannot ...
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43 views

Spectral density of 1-bit nonlinear detector in terms of analog spectral density

Suppose we have a time dependent noise signal $\theta(t)$. We sample $\theta(t)$ with a device which has 1 bit of resolution and is itself stochastic in the sense that the readout value $u$ of the ...
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20 views

Help needed with the integral of an infinite series [migrated]

Can you please help me with the integral of this series? I came across it in a signal processing paper and haven't been able to figure out the solution myself. $$ ...
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2answers
49 views

System response: LTI system for $x[n] = \sin(\frac{\pi n}{4})$

Consider the LTI system with frequency response $$H(e^{j\omega}) = \frac{1-e^{-j2\omega}}{1+\frac{1}{2}e^{-j4 \omega}}, -\pi < \omega < \pi$$ Determine the output $y[n]$ for all $n$ if the input ...
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1answer
67 views

Any good C# library for signal processing?

Does anyone can link me to a good C# DSP library? I saw some good C++ libraries but I don't have much with C++. Is there any way to wrap them ? My main porpuse is to apply some filters(Lowpass, ...
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14 views

Zero Cross Rating synchronization

I send some pure sinuses that are representing bits. I found that after some bits the system is losing synchromization so for example: if I want to catch a 13Khz sinus I get 12.8K. I use ZCR to ...
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39 views

DFT: Basis functions and Significance of dividing frequency by Sample length

A time domain signal can be decomposed into sinusoids which are based on basis functions. For a N sampled input, a cosine basis function is defined as: $$C_k[i] = \cos\left[\dfrac{2\pi k ...
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How to shift with spline interpolation?

I have a sampled pulse shape: $ h = [1, 0.5]$ and I do not know what is its real underlying continuous-time pulse. I want to compute the samples of $h(t-\Delta t)$. If I write the continuous pulse ...
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1answer
48 views

find the phase coherence factor?

How to find out the phase coherence factor from the two different discrete signal ? For example: $$x_1=\sin((2 \pi \cdot 50 i) + 30)$$ $$x_2=\sin((2 \pi \cdot 50 i) + 60)$$
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4answers
125 views

What kind of features can I extract from this signal

I want to monitor (automatic-)gearbox failures on some vehicles. For each vehicle I have a captured signal representing the selected gear at each one millisecond. An example of two signals are shown ...
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1answer
14 views

Transform a continuous time differential equation of a Low Pass Filter to discrete time

Assuming I have a linear differential equation of first order low pass filter: $$RC*y(t)'+y(t) = x(t) $$ And Assuming i know now that the input x(t) is being sampled at a rate of $T_s$ how can now ...
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1answer
38 views

Confusion related to PN sequence : Terminology and application in statistical signal processing

A Pseudo-random Noise (PN) sequence is a sequence of binary numbers, e.g. ±1, which appears to be random; but is in fact perfectly deterministic. The sequence appears to be random in the sense that ...
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0answers
16 views

Get discrete point from frequency response

If we have b=[1 2 3] discrete points and we want to frequency response with 30 uniformly distributed dense grid which are between [0,3], are every points of b certainly represent from 10 frequency ...
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1answer
34 views

Fir filter not working according to frequency response

I have designed a FIR filter with following parameters fs=30, f_pass1 = 1, stop1 = 0.5, f_pass2 = 3, f_stop2 = 4, A_pass = 1,A_stop = 40 Here is code : ...
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0answers
20 views

Identify correlated colored noises that affect a signal

In the process of signal + noise, which is not stationary. In this case how could I a. determine what autocorrelated noise colors affect a signal. b. What mix of correlated colors affect the signal ...
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1answer
52 views

Detecting a specific pop in a real time audio signal

I am listening for a very definite pop in a real time audio signal. So far I have managed to get the audio signal in at a sampling rate of 44100.0 Hz and 2048 frames per second. I have visualized the ...
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0answers
38 views

how to find the distance of the root from the origin?

Good Day, I have 9 polynomial roots. i have plotted the roots. my problems are: 1)how to find the distance of the roots from origin? I want to find the distance of all the roots from the origin. 2) ...
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1answer
40 views

How to plot the root of polynomial in Matlab?

I obtained this polynomial equations: $$A(z) = 1 - 0.7987 z^{-1} - 0.125 z^{-2} - 0.511 z^{-3} + 0.06889 z^{-4} + 0.3465 z^{-5} + 0.4809 z^{-6} + 0.04951 z^{-7} - 0.5298 z^{-8} + 0.1828 z^{-9}$$ How ...
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3answers
81 views

Uncorrelated but overlapping spectrum.

This answer may be straight forward but I cannot figure out. One can understand the difference between cross-correlation and convolution from the link below: What is the difference between ...
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1answer
32 views

Condition for optimal value to be the average

In many single parameter estimation process average is the optimal. Can anyone tell under what condition average is optimal? For example is average optimal if the data is iid, Gaussian or something ...
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2answers
64 views

EM algorithm and Kalman filter

I am new to the subject of Kalman filtering and therefore my question might seem trivial. I see that there is a tight connection between Kalman filter and EM algorithm when one wants to predict the ...
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1answer
120 views

Zero Padding of FFT

There are many question related to the zero padding a time domain signal to get more frequency bins after performing Fourier transform. As I understand this process is equivalent to trigonometric ...
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1answer
43 views

For linear IIR digital filter, what happens for negative frequencies?

By negative frequency, I refer to Fourier transform. Often, the frequency response of a digital filter is only displayed for positive frequencies. For a linear IIR digital filter, what happens for ...
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1answer
144 views

Expectation maximization of moving average with binary source input

I am trying to do blind system identification of a univariate linear FIR model: I am unsure if the approach is correct or not and any help to further proceed with the maximization will be great. ...
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2answers
52 views

Digital signal derivative

I'm new to signal processing and I need your help: I have an array of 128 elements (call it Window) filled with 128 samples taken from a sensor. I was wondering how ...