Questions tagged [continuous-signals]
A continuous signal or a continuous-time signal is a varying quantity (a signal) whose domain, which is often time, is a continuum.
442
questions
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1answer
33 views
Frequency component not filtered properly
Are frequency components other than wanted signal present in the output? If yes then why does it not disturb the original signal? I think all practical filter responses are not ideal, so all frequency ...
0
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1answer
105 views
Linearity of the given system
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:
\...
0
votes
1answer
30 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 ...
1
vote
2answers
389 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 ...
2
votes
5answers
1k 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 ...
0
votes
1answer
28 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 ...
0
votes
3answers
665 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 ...
0
votes
1answer
124 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 ...
0
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1answer
556 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 ...
0
votes
1answer
218 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) ...
1
vote
2answers
110 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
votes
1answer
317 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\...
0
votes
1answer
26 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
vote
1answer
79 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
336 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.
1
vote
1answer
469 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 ...
0
votes
2answers
116 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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votes
2answers
482 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 ...
0
votes
1answer
135 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?
0
votes
2answers
3k 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
vote
1answer
218 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
vote
0answers
28 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 ...
0
votes
2answers
169 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 ...
0
votes
1answer
124 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 ...
0
votes
1answer
80 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 ...
1
vote
2answers
62 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 ...
0
votes
1answer
558 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 ...
0
votes
0answers
25 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-...
0
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1answer
26 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
478 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 ...
1
vote
0answers
90 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
vote
1answer
42 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 ...
0
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0answers
82 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:
...
0
votes
2answers
4k 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?
0
votes
1answer
26 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)>...
0
votes
2answers
183 views
Problem with Convolution in MIMO System
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 ...
2
votes
1answer
232 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
1k 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 ...
0
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0answers
36 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\...
2
votes
1answer
236 views
Eigenfunction property for LTI sinusoidal and the sinusoidal steady-state response
All LTI systems possess the eigenfunction property for complex exponential inputs. That is (restricting our attention to periodic complex exponentials), if $e^{j\omega_k t}$ is an input to the LTI ...
2
votes
1answer
1k views
Designing high-pass filters using impulse invariance
One of the main disadvantages of realizing digital filters using impulse invariance is aliasing. According to the Nyquist sampling criterion, in order for the frequency response of the digital filter ...
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2answers
1k views
Why Derivative/Integration in time domain act as Highpass/Lowpass filter in frequency domain respectivly? [closed]
It is one of Fourier transform properties
1
vote
1answer
82 views
Is it possible to replace an integrator system with an equivalent differentiator?
I have a system whose input-output relation is as follows
$$y(t)=x(t)+\int_{-\infty }^{t} x(\tau) \,\mathrm d \tau$$
Can I create an equivalent system by using differentiators rather than ...
0
votes
1answer
401 views
Using the flip-and-drag method to draw a convolution
So, we are asked to graphically convolve (using the flip-and-drag method) the following pair of signals: $$x_1(t) = \delta(t+1)-2\delta(t-1) \ \ \ \ \ \ \ \ \ \ \ \ \ x_2(t) = \begin{cases} -1-2t, &...
0
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1answer
22 views
How do I simulate a purely real signal being received on multiple antennae in an array?
I have a signal created at baseband and then transmitted as $$\Re\{s_{bb}*e^{2\pi f_ct}\}$$ which is then received at a 5 element array for further processing. How do I interpret the real signal at ...
0
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1answer
49 views
impulse response of a system from its step response;confusion
If the step response of a system is given as $$c(t)=(10e^{-5t}-2e^{-10t}+1)u(t)$$
then its impulse response is _______?
My Approach:
we know: $$h(t)= \frac {d}{dt} c(t)$$
Process(1):
$$h(t)= \{ ...
2
votes
1answer
42 views
How is the energy conservation principle preserved in the case mentioned below?
Suppose there are 2 sinusoidal signals $\cos(\omega t)$ and $\cos(\omega t)$, which implies that their individual power is $1/2$ unit and total power is $1$ unit. When added, the signal $2\cos(\omega ...
0
votes
1answer
65 views
Impulse Invariant mapping [closed]
Can someone help me to better understand the Impulse Invariant mapping? :
$$h[n] = T \cdot h(nT)$$
I don't understand why the discrete-time impulse response, $h[n]$, is taken from the sampled ...
1
vote
1answer
2k views
Proof of the convolution property of Fourier Series in continuous time
I am facing problem in understanding the proof of Convolution property of Fourier Series (FS) in continuous time CT;
that is: $$\mathrm{FS} \big\{x_1(t)\star x_2(t)\big\}=T\sum_{n=-\infty}^{\infty}...
1
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1answer
3k views
Impulse response of ideal filters
I am aware that an ideal low-pass filter in both continuous time and discrete time has a $\mathrm{sinc}$ impulse response. What would the impulse response of an ideal high-pass or band-pass filter ...
