A continuous signal or a continuous-time signal is a varying quantity (a signal) whose domain, which is often time, is a continuum.
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21 views
Expressing a square as product of rect functions
A square is centered at origin and length of one of its side is 'a' units.
In terms of rect functions, such a square can be expressed as product of two rect functions, i.e., $f_a(x,y) = A [rect(mx)] ...
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1answer
25 views
Frequency component not filtered properly
Does frequency component other than wanted signal present in output if yes than why it not disturb original signal??? I think all practical filter response are not ideal so all frequency component ...
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1answer
49 views
Time scaling of a signal [on hold]
I know that amplitude of $u(t)$ is 1. Now if we make $t$ to be $t/2$ will the amplitude be halved?
-1
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1answer
61 views
Linearity of the given system [closed]
I am given the following system and I am checking the additive property:
$$y(t)=x(e^t)$$
where $y(t)$ is the output and $x(t)$ is the input given to the system.
Now this is what I did so far:
\...
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0answers
34 views
bandwidth of a signal
I have a signal $s(t)$, the bandwith is $B$. I'm doing the fourier transform $S(\nu)$ and I'm adding zeros to the spectrum. I get a new signal $u(t)$
Is the bandwith of the signal $u(t)$ equal to ...
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1answer
25 views
Finding Harmonics Analytically
I've always obtained harmonics using simulation and never by hand.
My question is how can someone find the harmonics for a signal (say a square wave) by hand? What equations come in handy for finding ...
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1answer
24 views
How to calculate the power of a finite length signal?
I am confused with these concepts. If the signal is expressed as r(t), I know the power of the signal is given by:
But if the the length of signal T is finite and cannot approach infinity, how can I ...
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4answers
75 views
Difference Between Dirac delta and unit impulse function
The definition of Dirac delta function states that it gives a value of $\infty$ at t=0 and 0 elsewhere.
But, the definition of unit impulse function states that it gives a value of 1 at t=0 and 0 ...
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1answer
19 views
identify equilibrium region after large transient
I am looking at data from a mechanical system under an unsteady load. I'm trying to find the simplest way to identify the portion of the signal once the system reaches its new equilibrium. Here's a ...
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3answers
62 views
What is the magnitude of the impulse function at t=0?
The unit impulse function, in a few textbooks that I have referred, has a value of 0 at t≠0 , and an area of unity (1). The height of the impulse function also tends to infinity at t=0. But since it's ...
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1answer
79 views
Show that any continuous-time signal $x(t)$ can be represented as $x(t)= x_e(t) + x_o(t)$
Show that any continuous-time signal $x(t)$ can be represented as $x(t)= x_e(t) + x_o(t)$
where $x_e(t) =\frac{1}{2}[x(t) + x(-t)]$ and $x_o(t) = \frac{1}{2}
[x(t) − x(-t)]$
are even and odd ...
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0answers
10 views
Cut two signals from a correlated signal
I have the following situation, I did ACF auto correlation between temperature and strain. I got a shifted signal in temperature and I already shifted it.
Of course the shifted signal has shorter ...
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1answer
24 views
Negative exponential signal's energy and power
Earlier I have dealt with exponential functions multiplied with unit step function. But, energy and power of exponential function alone comes out to be infinite when I put limits of the integrals to ...
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1answer
45 views
Properties of Invertible System [closed]
I have come to the understanding that if these three properties hold true then the system is a memory system:
1) Time Scaling:
$$y(t)=x(2t)\,,$$
2) Time Shifting:
$$y(t)=x(t+2)\,,$$
3) ...
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0answers
24 views
How to select Input parameters of FIR band pass filter (narrow band e.g Alpha (8-12 Hz)). A basic question?
I have to filter eeg data (500 samples) offline using a FIR bandpass filter for alpha rhythms (8-12 Hz) providing the fixed order of filter (i-e., 128).
Can some one explain what should be the ...
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0answers
23 views
Where Can I find Data set signals of noise from a city?
I am looking any noise signals from a city (any). I mean two option. The best option will be getting signals in real time from a city (could be near to the traffic or a park) but outdoor. or get ...
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2answers
69 views
Adding/subtracting sinusoids
I'm trying to calculate resultant function from adding two sinusoids:
$9\sin(\omega t + \tfrac{\pi}{3})$ and $-7\sin(\omega t - \tfrac{3\pi}{8})$
The correct answer is $14.38\sin(\omega t + 1.444)$, ...
2
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1answer
57 views
Bridging CTFT and DTFT for a cosine
I'm trying to understand how I can start from the CTFT of a signal and end up with a DTFT.
For example if I take a basic example:
$$
x(t) = cos(\omega_x \cdot t) = \frac{1}{2} \cdot \left( e^{j\...
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1answer
17 views
Conversion of airflow signal into 1-D as a input for CNN [closed]
Trying to detect apnea from airflow signal. I have 100 files of the patient each file contains at least 8 hours of data and sampling rate is 32 Hz. How to prepare my dataset which is used as an input ...
1
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1answer
36 views
Separating two frequency component
How can we separate two frequency component when they get mixed means when signal get mixed with noise how receiver can judge which part is signal and which is noise ?
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3answers
109 views
Is $\arctan(t)$ an energy or power signal?
Is the function $\arctan(t)$ an energy or power signal?
I've tried working out the integrals for energy and power but I get stuck on both.
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1answer
56 views
How can I determine the order of filter?
This is my first study about signal analysing. I'm very confused about filter order. My problem is how can I know whether its 12-th order, or 2nd order like the book says so? I already knew that slope ...
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0answers
18 views
multi-user communications techniques
I am working on multi-user communications. But I saw several differences in communication with one user.
For example, there are several techniques to compensate for Doppler in a communication with ...
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2answers
32 views
Reconciling Continuous and Discrete Complex Domains
Having taken some courses in Systems and Stability dealing mostly with continuous time signals, I am accustomed to thinking about the Laplace and Fourier transforms dealing with complex and pure ...
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2answers
48 views
Is there a specific preferred order of operation on signals?
Basic Signal Operations Performed on dependent variables-- The periodicity of the signal is varied by modifying the horizontal axis values, while the amplitude or the strength remains constant. These ...
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1answer
27 views
PN code generation
Can we generate PN codes (maximal length sequence) using this technique in Matlab where L is the PN length?
pn=2*(rand(1,L)>0.5)-1
If yes, why?
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2answers
134 views
Understanding the frequency domain [duplicate]
I'm trying to understand what frequency domain is. I found general explanations on the Internet, for example:
frequency-domain graph shows how much of the signal lies within each given frequency band ...
1
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1answer
61 views
Determining sampling rate for signal reconstruction
I want to know how to determine the signal sampling rate required to reconstruct electrical signals whose frequency components are unknown, such as, for example, signals of charge/discharge voltage on ...
1
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0answers
18 views
Multiplicative Input-Dependent Noise [closed]
This question might not be exactly suitable to the question format of StackExchange but I couldn't find a better way to put it forward.
Lately, I have been dealing with ECG Signal processing and due ...
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2answers
70 views
How to convert a sound signal function to wave file? [closed]
I am new to understanding sound signals. A sound signal, as far as I know, is a real function of time $x:[0,\infty)\to \Bbb R$. For example, $x(t)=\sin(t)$ is a sinusoidal signal.
What is $x(t)$. For ...
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1answer
42 views
methods of crest factor minimization
i am studying the methodes CF minimization. and have a doubt.
in each methods there are steps with DFT and IDFT or like this FFT and IFFT.
Everyone provides the fact, that they use DFT and IDFT for ...
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1answer
42 views
Homodyne concept of receiver
I would like to understand a concept of homodyne architecture of I-Q demodulator and how the wave looks like at each step.
It is a bandpass Signal:
Step 1: multiplication with cos and sin wave. I ...
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0answers
28 views
How to calculate FFT when many samples are observed?
I was given a classwork(which I flunked) where a continuous time wave of the format below was given:
$x(t) = A\sin(\omega_1 t) + A\sin(\omega_2 t)$.
with different frequencies for $\omega_1$ and $\...
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2answers
47 views
Fourier series of $cos(\omega_0 t)$ in continuous time
Can any one please help me with understanding how we can calculate the Fourier series of Cos(w0t) using the formula:
I saw that they did the following calculus, but I Don't really understand how we ...
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1answer
33 views
Converting Time Shift to Phase Shift
I have just started taking signal & systems lessons and here is my question:
If we say that x0(t) = A.cos(w0t). (a cosine signal with zero phase shift, w0 ...
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0answers
24 views
How does this digital signal controlling a switch in the circuit affect the output voltage?
Suppose you have a circuit which has the input signal $x(t)=2\sin (ω_ot + \pi/6)$. The switch in the circuit is controlled with a digital signal of the form: $s(t)=\sum_{k=-\infty}^{+\infty} (u(t+ε-...
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0answers
95 views
How to do cross correlation in real time?
I want to measure the signal similarities between two time domain signals a and b in real time. I do not know where to start. I think cross correlation might help but not sure how. Please guide me :-)
...
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1answer
20 views
Investigating correlation for unequal signal lengths
I have measurements from two tablet sensors. The first sensor measures the touch pressure applied to the tablet and the second sensor is the acceleration of the tablet (in z direction). The sensor ...
3
votes
1answer
117 views
What techniques are available for correcting constellation rotation due to phase ambiguity?
In order for a receiver to recover a baseband signal, it needs a carrier signal equivalent to that used by the transmitter for upconverting the original baseband signal. Unless pilot tones are used, a ...
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0answers
43 views
Basic question on sampling frequency relationship with sampling rate?
I'm using Matlab and have a signal that I'm simulating and I want to take the fft of the signal eventually. The intermediate steps performed is fixing the number of samples and the samples per meter.
...
1
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0answers
65 views
How to generate the amplitude of a signal with a certain power spectral density?
I am a newbie. If I posted a question someone else already asked, please forgive me. Thank you!
Now, I have a power spectral density named $P(f)$ as a function of $f$. Let's say this function is ...
1
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1answer
32 views
Need help deriving the energy of a signal
I am solving old exam problems in preparation of my exam in signals, and I'm having trouble with a question.
For a continuous aperiodic signal with the spectrum $X(\omega)=\exp(-\omega^2)$
I am to ...
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0answers
80 views
Why does bandpass performance break down at low frequencies? [duplicate]
I've got a basic bandpass filter design that works great at higher frequencies, but breaks down at around 150 Hz. Here's the MATLAB code:
...
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2answers
432 views
Energy of Sinc function
How to find energy of sinc function $x(t) = \frac{\sin \pi t}{\pi t}$ with out the help of Fourier transform or Parseval's theorem?
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1answer
21 views
What would be the proper notation for denoting part of signal that satisfies a condition?
I have a signal $E(t)$ which start at $t=0$ and dies out overtime. What would be a proper notation to specify part of which is above a certain threshold (say for e.g. C)?. Is $E_{interested} = E(t)>...
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0answers
15 views
Can the Tonality index in psychoacoustics model be positive?
I have an issue with understanding the attached equation of Calculating the Tonality index.
If you trace the equation, it appears that it is always less than 1 because the spectrum unpredictability (...
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2answers
107 views
Problem with convolution
For a flat fading channel (SISO system) we have:
$y=h \star s+n$
But for a mimo system, we have:
$y=Hx+n$ with $H \in \mathbb{C}^{N_r \times N_t}$
Why is there not the product of convolution for a ...
1
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1answer
69 views
Fourier coefficients of sum of two functions with different fundamental periods?
If we assume $\quad x(t)\leftrightarrow a_k\:$ and it is periodic with fundamental period T.
How can we determine the fourier coefficients of the sum
$x(t-7)+x(-2t+3)$
I know that $x(t-7)\...
2
votes
3answers
207 views
What is the filter with the less phase shift?
I have to analyze a dynamic signal but there is too much noise so I applied low pass filter but then there is too much phase shift.So what is the most reactive filter I can apply to my signal ?
Best ...
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0answers
35 views
How can we find the signal power of $x_{out}(t)=\frac{1}{2}Am(t)\cos \theta$?
I am trying to solve the following question:
I have partially worked out the problem and we have:
$$x_{out}(t)=\frac{1}{2}Am(t)\cos \theta,$$
which is the output of the LPF.
and
$$x(t)=Am(t)\cos (2\...
