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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24 views

How to prove: high-slope/more change is high freq part of signal

Generally, everyone knows that "the part of signal with high-slope is the high frequency part." What is the definition or theory behind it? How to prove this well-known thing? perhaps, I miss ...
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0answers
15 views

What is the difference between a sampled time system and a discrete time system?

I am trying to evaluate whether I should control a system in simulink using sampled data system or discrete time system. The discrete model is as follows: The sampled time system is as follows ...
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1answer
42 views

Kiss fft does not work after giving it more than 32 samples

I am trying to take data from an accelerometer and apply Kiss FFT to the samples. I'm using a Freescale Kinetis FRDM-K22F board. I want to use 64 samples, but when I run the program I get an error ...
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0answers
42 views

How to check whether a continuous signal is periodic or not?

How to check if a continuous signal is Periodic or not? My notes says $\cos(\frac{3}{2}\pi t)$ is periodic because $T=4/3$. And $\cos(\frac{3}{2}t)$ is not periodic as $T=4\pi/3$.
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3answers
77 views

Sampling theorem and signals explained to a mathematician

Let $f:\left(-\frac T2,\frac T2\right)\to\mathbb{R}$ for some $T>0$. The Fourier coefficients of $f$ are $$\left\{\begin{matrix}a_0&=&\displaystyle\frac ...
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1answer
37 views

Obtain transfer function from signal flow graph

I have a pretty complex signal flow graph with all the blocks and the branches completely describing an analog filter, in the Laplace complex variable s. The signal $X(s)$ is the input and $Y(s)$ is ...
-3
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1answer
60 views

Ideal BandPass Filter

Let suppose x(t)=$\sum\limits_{k=-∞}^∞ R(t-kT)$ $R(t) = \begin{cases}1 &[0,2T] \\ 0 & \text{otherwise} \end{cases}$ x(t) is the input to an ideal bandpass filter with $\text{BandWidth} = ...
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1answer
32 views

Determine Frequency Resolution samples

Can someone tell me if the way I solved this problem is right? Suppose I have a signal $X_a(t)= 0.5cos(700πt)+0.6cos(720πt)+0.1cos(780πt)$ where $F_s=8000Hz$ I want to determine the minimum samples ...
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1answer
45 views

Sampling orthogonal signals

Suppose I have two signals $f,g$ which are orthogonal in the sense of the usual inner product on $\mathbb R^d$. Then if I'm not mistaken these signals have disjoint spectral support, i.e their fourier ...
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1answer
47 views

Analog signal can be discrete time?

I am new to this site and field too.I always thought analog is continouos and digital signal is discete. I read this today and got confused about analog signal Analog can be >continuous time(CT)or ...
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1answer
24 views

Adding Dirac Delta with Unit Step

What does the graph of the function $x(t)=-\delta(t)+u(t)$ look like? $$\delta(t)\ldots\text{ Dirac delta impulse}\\ u(t)\ldots\text{unit step function}$$ Will the impulse at the origin start ...
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2answers
57 views

Prove using superposition that an LTI system is linear

Given an LTI system of the form: $$ \frac{d}{dt}{x}(t) = {A} {x}(t) \ + \ {B} {u}(t) $$ where ${x}(t)$ is the state variable, ${u}(t)$ an input and ${A}$ and ${B}$ constants, how does one show, by ...
2
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2answers
78 views

Effects of DC offset on a signal

What are some of the reasons why DC offset is considered undesirable for a timeseries signal other than wastage of power during transmission ? Specifically, How does it cause spectral leakage and out ...
0
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1answer
104 views

Additive but not homogeneous continuous system?

I am trying to find an example of a continuous system that is homogeneous, but not additive. So far, the only example I could find was an example from this page, which describes system as $y(t) = ...
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3answers
63 views

Fourier transform of triangular function

Determine $X(\omega)$. $g(t)$: I understand how to create a box from [-1,1] of amplitude 1/2. $x(t) = g(t) * g(t)$ $X(\omega) = G(\omega)G(\omega)$ the solution I am seeing says that $G(\omega) ...
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2answers
72 views

“Perfect waveform” for cross-correlations?

I am well versed in cross-correlations, as my masters thesis heavily relied on them for music classification and beat detection. So this question focuses more on the signals that I am running an ...
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0answers
25 views

Continuum removal in spectral imaging

In reflectance spectroscopy, you often get curves like this one (blue line, x axis is wavelength in micrometers, and y axis is % reflectance): Usually, geologists use "continuum removal" to ...
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1answer
66 views

Extending a waveform

Apologies if this makes no sense or seems rather simple, I'm a Matlab newbie. Basically, I've got a .wav audio waveform which I am resampling to various different frequencies and then trimming the ...
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1answer
170 views

Why these harmonics always present?

I am using Audio Precision 2700 to test some test vectors. I have connected resistor banks as class - d power amp's load, and tap from this resistor using a XLR cable to the AP. When my power amp ...
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0answers
17 views

Time invariance and time variance [duplicate]

How can I write a MATLAB program that takes the given system described in terms input x(t) and output y(t) relations is input and finds out whether it is time-invariant or not?
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1answer
57 views

Usefulness of Matrix Notation for Linear Periodically Time-Variant Transformations

I am quit puzzled about a notation I found in Gardner's 1986 book titled Introduction to Random Processes. It is in the chapter on Cyclostationary Processes at section 12.4 which pertains to Linear ...
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0answers
29 views

What are some interesting things I can do with EEG data?

I have an EEG device and would like to experiment with it a bit. Some of the data I can read from the device, in real time, are: ...
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2answers
36 views

Spectral Content of two waveforms

I have found this interesting question here: Which of these two waveforms has a richer spectral content, and why? Intuitively speaking, I think that the first one is richer, but I cant really ...
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2answers
59 views

Generate a BPSK modulated signal with non zero mean [closed]

I want to generate a BPSK modulated signal with non zero mean. I don't know how to add a non zero mean.
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0answers
119 views

How can I simulate a broadband ultrasound transducer in Matlab?

I am using a Matlab model to send a broadband acoustic pulse across a fluid. The centre frequency should be 50kHz with 100% bandwidth. It has been suggested that I apply a window the pulse to ...
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1answer
184 views

What are the advantages and disadvantages of the Ridgelet transform?

I used continuous wavelet transform (CWT) to analyze the behavior of a 1-D smooth signal(extracting its modal property, damping and frequency components)in my research. Now someone asked: Why the ...
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1answer
45 views

minimum frequency in periodic components

Suppose we have the following signal model $y(t) = A_1\sin(\omega_1 t+\phi_1) + A_2\sin(\omega_2 t+\phi_2) + ... + A_p\sin(\omega_p t+\phi_p) + z(t)$ When we are sampling at sampling frequency ...
4
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1answer
93 views

“chirp” with arbitrary period

Say you have a linear chirp, which is a bit like a sinusoid with a gradually increasing period, but instead of the linearly increasing period, could you pick an arbitrary value, like the red line in ...
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1answer
38 views

Using the windowing Method

I'm trying to write a C program that can get the PSD of an recorded audio file, I'm using for the fftw3 library. I wrote a program that calculate the PSD so far ...
3
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1answer
68 views

Sinusoid with increasing frequency

How would you describe this signal? It's like a sinusoid but as if its frequency was constantly increasing: could you write down a mathematical description? Thanks. And no, this is not homework...
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0answers
121 views

Convolving two complex signals - relationship between phase

Suppose two continuous complex domain signals are convolved, how is the magnitude and phase of the resultant signal related to the magnitudes and phase of the original signals?
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1answer
51 views

Counter design for audio signals

I am designing a schematic in which a Counter is to be increased whenever a particular band of frequencies is received at the Audio input. We are receiving the audio input as electrical Signal and I ...
3
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1answer
86 views

Why $x(t) = \cos(\frac{\pi}{3}t)$ and $y(t) = \sin(\frac{\pi}{3}t)$ are considered identical signals?

Consider the following question that I toke from Signals and systems: Part I exercises, question 1: (b) With $x(t) = \cos(\omega_x(t + \tau_x) + \theta_x)$ and $y(t) = sin(\omega_y(t + \tau_y)+ ...
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1answer
93 views

First-order low pass filter with bounded derivative

Given a function $x(t)$ and a first order low-pass filter $\frac{dy}{dt} = \frac{1}{\alpha} (x(t) - y(t))$, is there a way to choose $\alpha$ analytically such that the derivative of $y(t)$ is ...
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0answers
28 views

Statistics of the output of a high bitrate signal filtered through a narrow band low pass filter

I was wondering what would be the statistics of the output of the filtering of an extremely wideband signal (e.g. 10 Gbps random data stream) through a narrowband low-pass filter (e.g. 10 MHz LP). I ...
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2answers
240 views

If low frequency travels longer distance, why our speech is not travelling longer distance?

It is know that low frequency signals travel longer distance that of high frequency signal. If so, our speech signal is low frequency signal, why it is not travelling further?
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49 views

How to find blood pressure from osciloscope image

We have measured the human blood pressure with the sphygmomanometer connected to relative senzor of the pressure and osciloscope. We measured the offset of the sensor as $U_{OFF}=1.01\ V$ and the ...
2
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1answer
199 views

Auto or cross correlation for synchronisation in MATLAB

I have multiples records of a motor sound, I would like to synchronize them first and then calculate their spectrogram. My question is how can I use the autocorrelation or the crosscorrelation to ...
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2answers
43 views

Continuous time-domain electrical signal that only has a finite number of possible values

I have recently started learning DSP and the book that I am reading challenges the readers to find a: continuous time-domain electrical signal that only has a finite number of amplitude values ...
2
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1answer
190 views

Order analysis or order tracking

Last week I've been trying to implement the Order Analysis in MATLAB in vain. I've read a lot of docs about it like this one , but I still can't figure it out. This will be my last shot. Say I have ...
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2answers
483 views

Difference between band pass vs. low pass + high pass?

I am reading a paper in which they filter EEG signal using a notch filter to remove the power supply component of 50 Hz, then a high pass filter at 0.3 Hz to remove artifacts resulting from breathing, ...
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0answers
43 views

The order analysis in MATLAB [duplicate]

Can anybody tell me how to calculate the order analysis / spectrum of a signal? I've been searching in vain. I want to use MATLAB to analyse the signal / sound of a motor. For more information about ...
1
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1answer
102 views

How to analyse the sound of Motor

I have a motor, that I want to analyse, using its sound, so I can its 'character' I was using the the simple fft, and figured out, that it wouldn't help, so I tried the order analysis, at least I ...
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0answers
29 views

Matlab:Sampling Curve into Frames and Plotting

I have a Output Curve of following characteristics http://i.imgur.com/hABfsiC.jpg Following is the data which represents the output curve cited above ...
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0answers
37 views

Help in simulink for detecting specific parts of the signals

I am modeling some real-time ECG signals in simulink, and as I detect the zero-crossings or the peak of the pulse for this signal, I want to display the samples at which this occurs in the scope. This ...
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1answer
162 views

Continuous-time mathematical formula for deconvolution filters

I have an elementary function $p:\mathbb{R}^2\rightarrow\mathbb{R}$ which (locally) represents an image. It's a polynomial, and its the result of the following 2D convolution: $$p=f\star G\star ...
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1answer
112 views

how to find the “Natural and Total Response” of the system

Hello there I am a Student. I need to know how to find the Natural and Total Response of the given system: where: $x(t)=e^{-t}u(t)$ and $y(0^+)=2, \dfrac{d}{dt}y(0^+)=3$. (If the image above is ...
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1answer
652 views

Convert normalized frequency to real frequency in AR model

Let us suppose that we have modeled signal using AR model, and suppose we have following model: I used spectral estimation function from MATLAB pyulear Now ...
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0answers
52 views

Disadvantageous of wavelet transform

i have question related to wavelet transform:we know that while Fourier transform is good for spectral analysis or which frequency components occurred in signal,it will not give information about at ...
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2answers
135 views

Spectral leakage - understanding the integer number of cycles while windowing

I am reading tutorials about windowing and have read following sentence: For an integer number of cycles, all smoothing windows yield the same peak amplitude reading and have excellent amplitude ...