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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Transmit power of non-orthogonal FDM

It is known that the total power of an OFDM signal equals to the sum of the powers on each individual subcarriers. I am a bit puzzled by the total transmit power of a generalized FDM system if ...
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1answer
33 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 ...
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1answer
53 views

When does the convolution of $2$ signals equals zero?

For example, how can I determine if the convolution of $x(t)$ with $y(t)$ is equal to $0$?
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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 $H(s)$?
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2answers
153 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 ...
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0answers
20 views

3D wiggle plot for an analytic signal: Heyser corkscrew/spiral

Just reading The Analytic Impulse, A. Duncan, 1988, I met the name "Heyser corkscrew" for the first time in my DSP life, for a cisoid. This representation is quite common for analytic signals, but ...
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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 ...
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20 views

Which of these features may not be needed or redundant?

I am trying to extract some features of the accelerometer sensor and during the feature extraction each 5 second segment in the array is windowed and features are generated from these windows. ...
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3answers
73 views

Determine whether a signal is increasing or decreasing over time

I have a signal (x-axis: Time, y-axis: Data) which has more than 10000 samples per second. The signal itself represents some physical data (e.g. speed, acceleration, etc.) and has some noise on it. ...
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2answers
25 views

Why must outputs be the same for a pair of inputs for a causal system?

I'm trying to get a good understanding of causality and I can't wrap my head around the first definition of it, as noted in this Wikipedia article: Definition 1: A system mapping $x$ to $y$ is ...
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2answers
67 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 ...
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2answers
93 views

Detecting outliers/noise from sensor data

I am trying to detect outliers/noise as indicated on the diagram below from sensor data. Can anyone advice how to go about it? I can only do this in python, so are there libraries in python that I can ...
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0answers
35 views

Average Asynchronous Resample Latency

Given a sample frequence of 1 Hz and periodic events. The latency of an event is the time difference to the next sampling point. What is the average latency over infinitely many events? Events are ...
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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}} ...
2
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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 ...
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1answer
38 views

square wave frequency representation

New to this signals stuff and i'm confused about the frequency representation of the square wave. Correct me if i'm wrong, a periodic square wave is composed of odd harmonics sine waves which are ...
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1answer
42 views

Fourier Transform of triangle function $x(t)=\Delta\left(\frac{t-1}{2}\right)$

Can you please tell me if my working is right for the Fourier Transform of this function: $$x(t)=\Delta\left(\frac{t-1}{2}\right)$$ My workings are: I have used the fourier transform standard ...
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1answer
40 views

convert Fourier tranform of a signal to $\omega$ form?

Suppose we have this signal: $x(t)=5 \sin(2\pi 1000 t) \cos(2\pi 10000 t)$ I calculated the Fourier transform as below: ...
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4answers
170 views

Sampling Theorem: How to know the value between two samples of a Signal

According to Sampling theorem, in order to reconstruct a signal we need to sample it at the rate => twice the highest frequency component of that signal. (provided signal is band limited). Let's say, ...
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25 views

How to calculate the step response and transfer function

The output system is: $x(t)$ -->(S)--> $y(t) = \int_{-\infty}^{t}x(\tau) d\tau$ I am still not sure whether my work is correct, please some one advise me. I know that a step response is the ...
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1answer
26 views

Memorylessness of simple delay system

As usual, $y(t)$ is the output signal of a system, and $x(t)$ is the input signal. I'm wondering whether or not a certain system has memory. It's easy for me to see that the system $y(t) = ...
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1answer
34 views

Proof of a CTFT property

How do I prove that the absolute value of CTFT of a positive continuous time signal is less than or equal to its value at central frequency(0)?
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3answers
48 views

Does the hold part in sample and hold turns the signal from discrete to continuous?

I am trying to link sample and hold to discrete and continuous time domain. Could someone please confirm: When sampling but not holding for "an extended" period of time, you have discrete samples. ...
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2answers
53 views

Complex signal transform

I must strengthen my knowledge in the mathematical properties of signals, and would like to know the following thing: if I have a complex signal, written in magnitude and phase, it's like if I have ...
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0answers
54 views

Output of an LTI System With Given Frequency Response?

I will have my final exam this week. While I was studing for it I coudn't solve this problem. I think that I should work more about Fourier Transforms. I m thinking that the solution can be obtain by ...
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2answers
209 views

how to generate a smooth sine wave with time varying frequency in matlab

I'm currently designing a knock sensor for my FSAE team's car and I'd like to be able to test various software strategies with a fairly realistic signal (at least more realistic than a couple sine ...
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1answer
55 views

How can I approximate a signal

I have a signal as the below figure. I am looking for some schemes to approximate the signal. I have found some ways for that task: Using basis function (polynomial) to approximate the signal ...
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2answers
68 views

Is the book wrong? — How to sketch frequency response obtained from H(z)?

This question is directly related to digital signal processing, so I am asking here. How to sketch frequency response obtained from $H(z)$? I'm adding an example and its solution below. I did not ...
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1answer
45 views

Advantages of Splines in Compressed sensing

I am working in compressed sensing, basically in ECG reconstruction Normally we were using biorthogonal wavelets for reconstruction. Someone advised me to use exponential spline basis instead of ...
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1answer
54 views

reducing MIPS in detecting tones

Currently our software is detecting tones using FFT and checking if there is only a single peak in frequency spectrum. Our software needs to know what kind of input it is before taking action. So we ...
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4answers
455 views

The difference between convolution and cross-correlation from a signal-analysis point of view

I am trying to understand the difference between convolution to cross-correlation. I have read an understood This answer. I also understand thepicture below. But, in terms of signal processing, (a ...
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0answers
9 views

extended unwrap(), locating sawtooth peaks (weight of pass-through silo vs time)

Given is a recorded saw-tooth-like signal. (It's a weight of a bulk solid silo, continuosly and slowly emptied almost all the time, and quickly filled from time to time - without interrupting ...
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1answer
25 views

What is concurrent Signal?

I have come across with the term 'concurrent signal'. What does this type of signal means? What are it's importance?
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18 views

Obtaining SNR from SINR - 802.15.4

In the 802.15.4 standard, the following equation is used to calculate the BER: $$BER = 0.5 e^{-SINR/2} $$ I would however for my simulations like to avoid using SINR but rather SNR. I would like to ...
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0answers
47 views

Remove microphone rustle / clothing rustle from raw audio data

Thank in advance for the help. I have several GB's of raw audio data that I have collected as part of a research study. This audio is divided up into individual samples approximately 30 seconds in ...
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1answer
26 views

How do I use MATLAB to obtain a continuous state equation from a transfer function and ode45 to solve it?

I have the following transfer function that I am trying to model in MATLAB with some additional unity white noise: $$G(s)=\frac{1}{s^3 + \beta s^2}$$ I used the following to obtain the ...
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1answer
30 views

Power of periodic signal

Given a signal $s(t) = e^{j(t+\pi)}$, I conclude that the signal is periodic with period $T=2\pi$, so its power should be $$P = \frac{1}{T}\int_{-T/2}^{T/2}|s(t)|^2dt= ...
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0answers
57 views

converting higher order transfer function in s-domanin to the cascaded biquad transfer functions, also in s-domain

I'm trying to convert a transfer function (tf) in s-domain (num: b17*s**18 + b16*s**17 + ... + b0, den= s**20 + a18*s**19 + ... a0) to cascade of the biquad ...
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1answer
16 views

Why ignores constant when applying integral into differential-equation.?

I studied how to draw 'Direct-form I' and 'Direct-form II' from differential equation. The book taught me like this: $$\mbox{Give equation: }{a_0}{y(t)}+{a_1}{y'(t)}+{a_2}{y''(t)} = ...
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2answers
116 views

About Fourier transform of periodic signal

In Fourier transform for periodic signal, I checked different books and I found a different explanation in each book. Let's take the explanation in Signals and Systems by Rajeshwari & Rao: The ...
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1answer
101 views

properties of System

I am studying Signals and Systems. Anyone, please help me to answer the problems. $y(t)=dx(t)/dt$ is time invariant: True or False ? $h(t)$ is the impulse response of an LTI system. If $h(t)$ is ...
2
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1answer
63 views

Using superposition and time invariance to find RL circuit response

I am confusing reading book by Chaparro (Signal System with Matlab) in example 2.7. He give a question, a RL circuit with unit-step source $ v(t) = u(t) $ will result response, $$ i(t) = (1- e^{-t}) ...
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1answer
47 views

Making sense of the delay formula between two sensors in an antenna array?

In the image above, there is a formula for the delay of a signal at a given sensor 'i' in an antenna array. I don't understand how they arrived at that formula. Each antenna array element is ...
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1answer
85 views

Confusion in CT Fourier Transform Proof

I am confused trying to understand the Proof of Fourier Transform from Oppenheim book Signals and Systems. I am pasting the equations directly from the book: ...
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0answers
177 views

Proof of Properties of Fourier series in CT

I feel problem in understanding the proof of Fourier series properties Time scaling $$b_k = \frac{1}{T}\int_{T}x(t)e^{jk\omega_0t}dt$$ $a$ - scaling factor $$ = ...
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3answers
80 views

magnitude and phase Fourier coefficients

While solving Fourier series coefficients in example, i found couple of things which confuse me. How the minus sign changes to plus sign $a_1= 1-\frac{1}{2j} = 1+\frac{1}{2}j$? After plotting the ...
2
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1answer
94 views

Mathematical model of a signal in Compressive Sampling

Currently I am reading a paper on Compressive Sampling, and trying to understand each and every parts of it. When I came across the mathematical model of the signal in paper, I got confused. I have ...
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1answer
81 views

Proof for determining Fourier coefficients

While determining Fourier coefficients we have this equation $$\int^{T}_{0} x(t) e^{-jn\omega_0t} dt = \sum^{+\infty}_{k\ =\ -\infty} a_k [\int^{T}_{0} e^{j(k-n)\omega_0t}dt]$$ I want to ask that how ...
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1answer
36 views

Value of $A_k$ in Fourier series

Fourier series in continuous time domain while representing $a_k$ in rectangular form $$ a_k = B_k + jC_k$$ But when using the value of $a_k$ in the main equation: $$ x(t) = a_0 + ...
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1answer
37 views

Fourier Series Proof

I want to ask Question about the Fourier series in continuous time domain while reading a book signals and systems Alan Oppenheim. I have confusion in understanding the statement on page 189 of its ...