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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3answers
80 views

Identifying steps in walking accelerometer

I have some recorded walking data from an android phone and want to determine when someones foot hits the ground using the acceleration data. I'm making an assumption here that the person will "bob" ...
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1answer
43 views

Energy of $\text{sinc}^2(kt)$ function multiplied by variable

I know how to determine the energy of $\text{sinc}^2(kt)$, but how does this change when I need to find the energy of $(kt)\cdot \text{sinc}^2(kt)$. If the $(kt)$ in front is squared (in energy ...
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1answer
40 views

PSD of a sum of two stationary real signals

I have 4 signals ($w_1(t),w_2(t),u_1(t),u_2(t)$ of which I know the power spectral densities (PSDs) $S_{w_1,w_1}(\omega),S_{w_2,w_2}(\omega),S_{u_1,u_1}(\omega),S_{u_2,u_2}(\omega)$ and the cross PSD $...
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1answer
28 views

What is the link between equation of a continuous signal versus equation of its sampled form?

I have just started DSP self-learning. I am a little confused by this 'end of the chapter' exercise question from Chapter 2 of "Understanding Digital signal processing" 3rd edition by Richard G. Lyons....
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1answer
40 views

Is calculus background a must for learn DSP? [closed]

I'm beginner in DSP and in the literature some Authors suggest Analog (Continuous) Signal Processing a prerequisite for learn DSP. But it demands calculus background, that I do not have. Is calculus ...
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1answer
77 views

Sampling signal after root raised cosine

I am generating series of 1 and 0. then pulse shaped them with root raised cosine and after than deciding to do match filtering and recovering the bits however it turns out that I am not getting the ...
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1answer
17 views

Relating phase shift to the ROL/ROR operations

Is phase-shifting in continuous-time analogous to the rotate-left (ROL) and rotate-right (ROR) operations in discrete-time?
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1answer
26 views

Graph of $[u(\tau)-u(\tau-4)]\cdot[u(t-\tau)-u(t-\tau-4)]$

I'm trying to visualize what would the following signal be like $$[u(\tau)-u(\tau-4)]\cdot[u(t-\tau)-u(t-\tau-4)]$$ Consider that $\tau$ is the independent variable here, $t$ is the shift variable. ...
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1answer
34 views

Help in sketching a CT signal with discontinuities

This is the Original signal: And I'm supposed to sketch $[x(t) + x(-t)] .u(t)$ I know that unit step signal will make the signal starts from 0 to $+\infty$ My problem is at key point (0) and key ...
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0answers
37 views

How do we find the Power Spectrum Density (PSD) and which data type is valid for that?

I want a simple explanation on how to find PSD and which type of data (in which units, I mean) can be used for doing so. If found similar interesting questions 1 & 2 and some on Mathworks, like ...
3
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1answer
70 views

How to do continuous signal processing (i.e without windowing)?

I'm working in speech recognition research, and I wonder if there is a way to analyse sound just like how ears do (i.e. without windowing), so for example to take some feature continuously with an ...
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1answer
34 views

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 ...
3
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1answer
49 views

Envelop detection with low sample rate?

I have a signal up to $3\textrm{ MHz}$. The ADC that sample it has a rate of $1.5\mu s$. So a full $T$ of the signal is $0.3\mu s$, and I can only sample each $1.5\mu s$. It sounds not enough, but I ...
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1answer
74 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
25 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 $H(s)$?
3
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2answers
168 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 domain,...
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0answers
32 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
38 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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0answers
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. ...
0
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3answers
109 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
28 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
73 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 Stability?...
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2answers
131 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
36 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
32 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}} HZ$...
2
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1answer
66 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
41 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 ...
1
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1answer
45 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
41 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: $X(f)=(j\frac{5}{4})[\delta(f-9000)+\delta(f+11000)-\delta(f-11000)-\...
2
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4answers
177 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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0answers
29 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
28 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) = \int_{t-...
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1answer
36 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
53 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
54 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 ...
0
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0answers
55 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 ...
0
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2answers
310 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
57 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 ...
3
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2answers
76 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 ...
0
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1answer
48 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 ...
1
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1answer
59 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 ...
5
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4answers
529 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
10 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 emptying....
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1answer
30 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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0answers
21 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
50 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
29 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
31 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= \frac{1}{2\pi}\int_{-\pi}^{\pi}|...
0
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0answers
74 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 ...
0
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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)} = {b_0}{x(t)}+{b_1}...