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

learn more… | top users | synonyms

1
vote
1answer
22 views

Envelop detection with low sample rate?

I have a signal up to 3Mhz. The ADC that sample it has a rate of 1.5us . So a full T of the signal is 0.3us, and I can only sample each 1.5us. It sounds not enough, but i don't need to reconstruct ...
1
vote
1answer
41 views

Features of a non-periodic signal for comparison

I am looking for comparing a signal (256 / 512 point discrete | non-periodic ) (obtained after extracting some features from the captured image) with a database of around 5000 signals (256 /512 point ...
1
vote
1answer
30 views

Problems calculating Z-transform

I am trying to solve a class exercise in which I am given the following, in Laplace domain: $$G(s)=\dfrac{e^{-Ts}}{s+3}$$ $$H(s)=\dfrac{1}{s}$$ And I need to calculate $\dfrac{C(z)}{R(z)}$, which is ...
0
votes
1answer
42 views

Output a sine wave from samples-limits?

Using a micro-processor of 48MHz, I am trying to output a sine wave from the DAC (digital to analog ), and I am not sure if my ...
0
votes
1answer
24 views

Behaviour of the poles in transfer function $H(s)$, given system properties

If a linear system is causal and its impulse response is an energy signal. What's the behaviour of the poles of $s$-domain transfer function $H(s)$?
1
vote
0answers
26 views

Unique signal extraction from a cumulated signal

I'd like to start off by saying that I am not very experienced at signal processing, so I apologise in advance if I do not explain everything properly the first time. I would like to analyse the ...
0
votes
2answers
33 views

A question about the concept of the time

$\delta[n+1]$ equals to one only $n+1 = 0$ ? If the 1. is true, so what does a signal $x[n+1] $ stand for? Is this signal causal or anticausal? I mean, if 1. is true, $n = -1$, so is this signal ...
1
vote
1answer
23 views

Real Time Goertzel Algorithm

Why is Goertzel Algorithm considered a block algorithm? Given that my input is bounded, couldn't I just run it forever (taking every sample that comes out after some length N) given a big enough word ...
0
votes
0answers
19 views

Simple sample and reconstruction code - MATLAB

I am trying to go from theory to code. I take x (let say 16KHz is continuous time) then I sample it in 2Khz So I do ...
0
votes
0answers
18 views

Is adding zeros part of the Hermitian Symmetry process?

I have been reading about DMT/OFDM and every source I find defines their system differently. I simply want to know if zero insertion is part of the Hermitian symmetry process that produces real OFDM ...
1
vote
1answer
39 views

Why does Fourier zero-fill interpolation pad the middle frequencies?

In this: http://dspguru.com/dsp/howtos/how-to-interpolate-in-time-domain-by-zero-padding-in-frequency-domain the author says that we can interpolate a signal by zero-padding the middle frequencies in ...
3
votes
2answers
60 views

what is nyquist rate of $h(t)\cdot h(t)$ and $h(t)\circledast h(t)$

Let's say we have $h_c(t)$ as a continuous-time signal with bandwidth $B$ and we would like to sample it. To be able to reconstruct it correctly, the sampling rate must be greater than $2B$. Now ...
0
votes
0answers
12 views

How can i plot the power spectrum in terms of time history representation of a signal?

I have a signal and How to plot the power spectrum in terms of time history representation as shown in the below figure in MATLAB. and also i would like to plot the spectrogram as shown in the ...
0
votes
1answer
36 views

Filter Design near Nyquist frequency (complex curve fitting)

I'm fitting IIR filters to a complex transfer function with Matlab's invfreqz.m. My fitting results are very good, but when I come very close to the Nyquist frequency the phase response runs to 0 and ...
7
votes
2answers
272 views

What really means stationary and non-stationary?

I really struggle to find out what really means stationary signal. There are some nice definitions in textbooks and wikipedia. But what that means in practice? To understand what is it, please answer ...
1
vote
1answer
37 views

Importance of Discrete Cosine Transform over High Pass filter?

I have recently studied few work where the low and high frequency components of an image is accessed using the discrete cosine transform (one such example is presented here). Low and High frequency ...
0
votes
2answers
35 views

How to interpret output of matched filter with complex input?

I have implemented a matched filter based on the Fourier Transform approach. In the real numbers domain that means that I use as the coefficients of my filter (B) the inverted time-samples of the ...
3
votes
2answers
152 views

Special case: Band-limited in time domain and band-limited in frequency domain

I know except for some special cases, aliasing is unavoidable. Assume we time-limit a function, $f(t)$, so that it is zero outside an interval say $[0,T]$ to form $y(t)$. Then, in the frequency ...
1
vote
0answers
13 views

Power Spectral Density Via Rank 1 Update

I know that I can find the autocorrelation matrix of a series of finite length sequences via rank-1 updates using the relation: $\mathbf{R}[k] = \frac{1}{k}\mathbf{R}[k-1] + ...
-2
votes
1answer
28 views

Calculate Energy and Power infinite signal (math)

So we have example: $$x[n]=\left(\frac{1}{2}\right)^nu[n]$$ and I want to find $E_\infty$. So I found by wild search that this can be solved using this: $$E_\infty = ...
0
votes
0answers
39 views

Choosing correct filter parameters for IMU sensor datas

I have a IMU sensor breakoutboard using ITG3701, LSM303D LinkProduct. This involves accelerometer, gyroscope and magnetometer. I have connected the sensors to a Arduino and sending the datas to ...
0
votes
1answer
39 views

How many non-zeros samples in convolution

If I have $b[n]$ of length 30 (30 non-zero samples) and $c[n]$ of length 40 (40 non-zero samples). How many non-zero samples will $a[n]=b[n] * c[n]$ have? (Note '$*$' is a convolution). I think ...
4
votes
2answers
183 views

What is the difference between natural response and zero input response?

I am new to DSP and was going through different responses of a system subjected to an input. My understanding of zero input response is: it is the response/output of the system when the input signal ...
3
votes
2answers
69 views

Adding “realistic” noise to signals of different amplitudes

I have a question regarding basic signal processing, which I have to start using since I have started studying fault isolation. The thing is, I have three computed signals, which are gathered in the ...
0
votes
2answers
31 views

How do we actually obtain samples to form discrete time samples? [closed]

I'm in my second week of an online DSP class and I'm still kinda lost on some of the concepts of what we are actually doing. I'm hoping you guys can help clear up my understanding. Please forgive me ...
1
vote
1answer
56 views

Why is the signum function $=2u(t) - 1$?

Basically I couldnt find proof for this anywhere though it's a very simple and basic equation.
1
vote
1answer
68 views

Combination of accelation signals from two devices

I have $x_A$, $y_A$, and $z_A$ acceleration signals collected from a smartphone and I call it: set $A$ and I also have $x_B$, $y_B$, and $z_B$ same acceleration signals from smartwatch: let's call ...
2
votes
2answers
76 views

Signal correlation vs Pearson correlation between signals

I have some data which are the sets of values uniformly distributed along some measure (simple example - along the time intervals). I tested both the coefficients and found the difference, some times ...
0
votes
1answer
70 views

Why does this reconstruction produce a phase shift from the original signal?

After an FFT of a signal is done, it is plotted as in the image below, with the original signal is on the first subplot. Using the magnitude and phase data of each frequency, it's reconstructed, ...
1
vote
2answers
65 views

Causal system, order of numerator and denominator [duplicate]

Is it true that if the order of numerator of a system function is larger than its denominator, then we can say that the system is causal? (Without finding R.O.C.) Is there similar thing for ...
0
votes
2answers
52 views

Synthesis DFT Filter Bank

I have a DFT bank analyzer with N channels, but the the bandwidth of the signal occupies only the first 2 channels, therefore I'll reconstruct only these and not entire full bandwidth. I'd like to ...
-1
votes
4answers
94 views

What is the real difference between DSP and AI/data science?

I am very much into DSP, but lately everybody is talking about "Data science" and ...
1
vote
1answer
27 views

Cost function for adaptive algorithms

I am having little difficulty to understand that why most of the adaptive algorithms use error power or addition of error power as cost function/minimization criterion. I have read that minimization ...
5
votes
2answers
123 views

Eigenfunctions of discrete-time LTI systems

Given a discrete-time signal x[n], how does one determine if it is an eigenfunction of a stable, discrete-time LTI system? For example, consider $5^nu[n]$ ...
1
vote
1answer
32 views

Transfer function of an Exponential system in Z domain

Hi, I am really confused with the system in the diagram. The input-output relation of the system is given by $y[n]=\exp(x^2[n])$ I need to find the transfer function of this system $Y(z)$ in ...
0
votes
1answer
27 views

finding maximum frequency

Assume we have: $$x_c(t)=\sum_{k=-9}^{9} a_k e^{j(2000\pi kt)}$$ and Fourier coefficients out of $$|k|>9$$ is zero. So, it is band-limited. The sampling frequency is:$$F_s=\frac {6} {10^{-6}} ...
1
vote
1answer
54 views

Downsampling in DWT algorithm

I was working on wavelet signal decomposition and got confused with the downsampling part of Discrete Wavelet Transform algorithm. If we consider a signal $\{a_0[0], ... ,a_0[N-1]\}$ of length N and ...
2
votes
1answer
59 views

$2\pi$ periodicity of discrete-time Fourier transform

In my signals and systems course, we have learned that the discrete-time Fourier transform is $2\pi$ periodic, but the continuous-time Fourier transform is not periodic in general. For reference, we ...
1
vote
0answers
58 views

Sampling and zero crossing

I am sampling a sine wave of 50Hz(stepped down from 230V) at the rate of 500KHz. For identifying disturbances in the wave, i was thinking of comparing a cycle of incoming sine values with reference ...
0
votes
0answers
29 views

questions on the wavelet digital filters

I am new in wavelet transform and digital filters. My knowledge on wavelet transforms was mainly from its applications with the implementation using Matlab or mathematica. So my question might be too ...
0
votes
0answers
23 views

Performing Shifting, flipping, and scaling (the correct order?)

I've asked similar question in here however I feel posting a new question is better than modifying the previous one. My understanding for carrying out the operations should be done in this order ...
0
votes
1answer
23 views

what is the correct answer for shifting and scaling this signal?

The discrete signal is provided in the following table: $$\begin{array}{|c|ccccccc|}\hline n& -3 & -2 & -1 & 0 & 1 & 2 & 3\\ \hline x[n] & 3 & 2 & 1 & ...
1
vote
0answers
30 views

connection between theory that is done in $L^2(\mathbb{R})$ and its application on discrete signal

I have problems understanding connection between theory that is done in $L^2(\mathbb{R})$ and its application to discrete signals. Look at this paper: ...
1
vote
0answers
36 views

Discrete Fourier Transform for text analysis?

I would like to determine the number of text-blocks verifying a roughly similar pattern. I have the intuition that I could do it using some Discrete Fourier Transform (DFT)-like methodology. Example: ...
0
votes
1answer
48 views

What would the plot of an two sided digital signal look like?

Please, take a look at section, 1.2.3 (Signal Duration), Page-03, of the book Shaum's Outlines: Digital Signal Processing by by Monson H. Hayes. According to the definition, I can imagine how a ...
0
votes
1answer
61 views

Question about ASK, correlation, and frequency domain

So I'm currently studying ASK (amplitude shift keying) and how it is modulated and demodulated. The modulation take out data signal, $M(t)$, and multiplies it with our carrier frequency, lets say ...
-2
votes
1answer
43 views

Find $X_s(f)$ of a sampled continuous signal

I've been trying to find the transform of the following signal, but have not been successful, any help would be greatly appreciated: Find $X_s(f)$ of the following signal the "mathematical DAC" ...
0
votes
0answers
52 views

Number of samples needed to convert a analog->digital, frequency bound, signal with decent quality to the Fourier domain

Similiar question(s) have been asked before, but I didn't fully get the answer I was looking for, so I figured I'd ask again. My excuses if there's something really basic in signal processing I've ...
3
votes
1answer
57 views

What is the relationship between passivity of impulse response and passivity of the system?

What I mean by passivity of impulse response is that the energy of impulse response for this system is less than the input impulse signal energy. For example, in a discrete-time system, considering ...
0
votes
1answer
87 views

Why is cos(n/6) aperiodic?

This is a very common example in most Signal Processing books I have come across. x(n) = cos($\frac{n}{6}$) is a non-periodic discrete signal because it doesn't satisfy the periodicity condition for ...