Signals Definition and 434 Threads

I got an SMS educating people how to find out the presence of a hidden cam in a trial room of a textile showroom or bathroom. It goes like this :- "If you can't make a call in the room,the there is a hidden cam. This is due to the interference of the fibre optic with the signal transfer."...

Whats the difference between a discrete time impulse and a continuous time impulse signal ?

Homework Statement An astronaut makes a round trip at 0.80 c to a star 20 light-years away, while her husband remains on Earth. Each sends the other a signal once a year by his or her own reckoning. Assume that the period of acceleration when the astronaut turns to head back home is small and...

Homework Statement What is that oscillatory component? And is my answer for the following correct? x(t) = u(t) H(s) = \frac{R}{R + sL} y(t) will contain oscillatory component if R > \frac{1}{L} True or False? Homework Equations Basic Laplace Transform: u(t) \longrightarrow...

Assistance on the below question are very very much appreciated! :D Been pondering about them for quite some time. Problem: A sensor was placed on a car engine to record its vibration. If the speed of the engine is 4rev/s. Which of the following is true? A. The amplitude spectrum of the...

Homework Statement The Dirac function (unit impulse) is defined as \delta(t) = 0 where t \neq 0 the integration of d(t) between -ve inf and +ve inf is 1. Now I picture this as a rectangle with no width and infinite height. In fact I think of the width (along the x axis) as (1/inf =...

If signals x(t) and y(t) are orthogonal and if z(t) = x(t) + y(t) then E_{z} = E_{x} + E_{y}: Proof: E_{z} => \int^{\infty}_{-\infty} {(x(t) + y(t))^{2}} dt => \int {(x(t) + y(t))^{2}}^{2} dt => \int (x^{2}(t)) + \int(y^{2}(t))dt + \int x(t)y(t)dt => E_{x} + E_{y} because \int...

Hi A human body is a chemical machine. Every process, such as walking, sleeping, thinking, etc., consumes energy but rate of energy consumption varies from one activity to another. I have been told that when some body part such as forehead, hand, is experiencing, a lot of energy is consumed...

I figure that intelligent life couldn't have formed until, at the very least, the second generation stars that started birthing forth carbon (maybe 3 billion years after the Big Bang?). On Earth, it took something like 2.5 billion years until multicellular life formed, and so maybe we can...

y(t) = x(t) + \int (t - \tau)x(\tau)d\tau for it to be linear, T[kx(t)] = kT[x(t)] i'm wondering if i also multiply x(tau) by k. at first i thought I'm not supposed to so i have T[kx(t)] = kx(t) + \int (t - \tau)x(\tau)d\tau and kT[x(t)] = k[x(t) + \int (t - \tau)x(\tau)d\tau] = kx(t) +...

Homework Statement Determine whether or not each of the following signals is periodic if signal is periodic determine the fundamental period (note that these are discrete not continuous signals) Show your solutions 1. x(n) = \cos^3(\frac{\pi(n)}{8}) 2. x(n) =...

Homework Statement Determine whether or not each of the following signals is periodic if signal is periodic determine the fundamental period (note that these are discrete not continuous signals) Show your solutions 1. x(n) = \cos^3(\frac{\pi(n)}{8}) 2. x(n) =...

Homework Statement Compute Y(t). Homework Equations Y(s)= (s(2s+11)+ω(8s+4ω^2))/((s^2+ω^2)(s+9)(s+2)) The Attempt at a Solution (s(2s+11)+ω(8s+4ω^2 ))/((s^2+ω^2)(s+9)(s+2))= A/(s^2+ω^2 )+B/(s+9)+C/(s+2) Every example I have looked at does not have the ω variable, but I...

Hello, I need to calculate the correlation betweeen a pair of eeg signals in various bands (delta, theta, alpha...). Before I do so, I am filtering out frequencies below 0.5 Hz. (and also notching out 50 Hz.) I wonder whether the phase changes introduced by these filtering operations would...

On page 7 of the attached document, it says that because "the above geometry does not depend on t", the trajectory of the first signal must be the same as the trajecotry of the second, just shifted by \Delta t. I don't understand: a) how it doesn't depend on t? there's a dt in the formula...

Hi friends, I'm new in this forum and very happy to be here. I need your guidance on what to do with my Signals and Systems course which I expect to turn into a failure. I'm studying Electronics Engineering and I think I'm going to fail Signals and Systems because I got 9 out of 100 on my first...

I have 2 questions:(at least answer on question) 1) What is an amplifier? Is amplifier or a booster are same thing? What does an amplification do with signals? If an booster/amplifier is connected in a DSL line so will it amplify DSL connection to get better speed? 2) How to make a portable...

As per the theory of general relativity nothing can travell faster than the speed of light. Therefore we would always be in the past light cone of a distant celestial body, say planet X in another solar system, that is 100 light years away. A minimum of 100 years would have to lapse before an...

From the lecture notes: h[n] = \frac{1}{2}(\delta[n] + delta[n-1]) via property: H(e^{j\Omega})=\sum_{-\infty}^{\infty}h[k]e^{-j\Omega k} becomes: H(e^{j\Omega})= \frac{1}{2}(1 + e^{-j\Omega}) than my lecture divided by e^{\frac{-j\Omega}{2}} resulting in: H(e^{j\Omega})=...

Homework Statement Input and system response is as follow: x[n] = r[n] - 2r[n - 1] + r[n - 2] h[n] = \delta[n - 2] The output is: y[n] = u[n - 3] Is that true? Homework Equations The Attempt at a Solution I draw the h[n] and x[n] and they looked as follows: As for...

Homework Statement The system with impulse response h(t) = a_{1}\delta(t-t_{1}) + a_{2}\delta(t-t_{2}). Is this system stable or not?Homework Equations The Attempt at a Solution I drew the h(t) response and I got something like that: but I don't really know how to prove it. There is no input...

I'm looking for a device that can record EM signals of unknown frequencies (unknown to me) emitted by devices. For example if I point my remote control at it and start pressing buttons it should record intermittent IR frequency surges. Or for example if I build an emitter to modulate an...

"Radio frequency (RF) is a rate of oscillation in the range of about 30 kHz to 300 GHz, which corresponds to the frequency of electrical signals normally used to produce and detect radio waves." - Quoted from Wikipedia. How can electrical signals be used to produce and detect radio waves...

hello friends, I have a voltage and current input signal in simulink which has a small phase shift between the two signals. Is their a way so that i can eliminate this phase difference to zero? thanks

Homework Statement The signal y(t) is generated by convolving a band limited signal x1(t) with another band limited signal x2(t) that is y(t)=x1(t)*x2(t) where: --> X1(jω)=0 for|ω| > 1000Π --> X2(jω)=0 for|ω| >2000Π Impulse train sampling is performed on y(t) to obtain: --> yp(t)=...

x(t) = t, 0 \leq t \leq 1; x(t) = 2-t, 1 \leq t \leq 2; x(t) = 0 ,otherwise. I want to draw this signal, and I have something similar to this Is that correct? Also this is not periodic right? I just want to be sure 100% Thanks!

Hi there, This is a different question I tried. The signal is given as x[n] = 2u[n+2] - 3u[n-2] +u[n-4], and it has values x[-2]=2, x[2]=-1 and x[4]=0. True or false? I think it's false cause If I plug in all the x in each case ie, -2, 2 and 4, into the signal, than I get 3 different...

Hi guys, I have this question in the book whether a signal is Power Signal or Energy Signal. From what I have read signal is an energy one if its time-averaged power is = 0, or its non periodic. For non-periodic signal V(t) \neq V(t+T) I tried to prove that V(t) = 230\sqrt{2} Sin...

Hello, I'm a newbie of signal processing, I would like to calculate a frf between two acceleration signals. I have several realizations of each signal. These signals are stationaries and they aren't triggered, so signal arrays doesn't have the same length. I have got these acceleration signal by...

Will we get a high frequency signal from convolving 2 high frequency signals? Also will we get a low frequency signal from convolving 2 low frequency signals? How about convolving one low and one high frequency signal? My intuition tells me its low frequency signal. Thanks for any...

Homework Statement Find the period of the signal x(t) = 2 + 4cos(40Pi*t) + 3cos(60Pi*t) + 4cos(120Pi*t). Homework Equations The Attempt at a Solution The fundamental frequency (fo) = 10 Hz, since that's the greatest common factor of all the frequencies of the cosine signals. So...

Not a specific question per se but... Is it possible to convolve a discrete-time signal with a continuous-time one? if you have x(n) and y(t) can you calculate the convolution of x and y (say, by taking y(t) for t in the set of integers or by treating each x(n) as its value multiplied by...

Hello.. Am an Electrical Engineer, my FYP concerns the artificial limbs... I made a small research about the nervous messages, and how it flows from the brain until it reaches the muscles. In the arm i found that there are 3 nerves (Ulnar, Median, and Radial nerve) which are responsible for arm...

I am a little confused about convolutions. I know that convolution is the multiplication and then integral of the two signals. The confusion starts at the commutative property. If i try to change the time-shift from signal to another for any 2 general functions or equations the commutative...

Obtain the digital words corresponding to the indicated analog signal levels, a through j, as shown in Figure P8.38, that would be assigned by an A/D system with 2 bits. http://img256.imageshack.us/f/eehmrw1.png/ a. None of the above b. a=11, b=01,c=10,d=01, and e=01 c...

Homework Statement At the beginning of the year 2000, country A had a population p of 100 million people. The birth rate is 4%/year and the death rate is 2%/year, compounded daily. Every day, 275 immigrants enter country A. Neglect leap-year effects. Write a difference equation for the...

Homework Statement \int_{-\infty}^{\infty}{u(t)e^{-t}(\delta(t+1)+\delta(t-1))dt Homework Equations \int_{-\infty}^{t}{u(t)dt = \left\{\begin{array}{cc}0,&\mbox{ if } t< 0\\t, & \mbox{ if } t>0\end{array}\right. \int_{-\infty}^{\infty}{f(t)\delta(t-a)dt} = f(a) The...

Hi, Suppose you have an OFDM signal, e.g. DVB-T. In this case the spacing between the carriers is 4464 Hz and there are 1705 carriers. So the total bandwidth is 7.61 Mhz in baseband. First: Am I right that the spectrum is wide but very sparse? So There is a peak at 0Hz, 4464 Hz, 8928 Hz...

how many types of brain signals are there? or if a person thinks of writing a word the signals that perform this action what are those called..? (brain signals is not my subject but i want this knowledge to further use it in a signals and systems project relating to human brain) thnx

(I posted this in the elctrical engineering forums because it's technically not homework, but it probably belongs here...it got no replies there) I'm hoping this thread can clear up some confusion I have with complex signals and moving back and forth from physical signals to the mathematical...

Hey, I'm hoping this thread can clear up some confusion I have with complex signals and moving back and forth from physical signals to the mathematical models. I'll probably ask some questions specifically, but if you would like to help me please treat this whole post as a question because I'll...

I have an application that requires me to multiplex between >7 sinusoidal signals (15v ~1-100kHz) with as little distortion as possible. I'm not really sure what would be the best way to go about doing this though. My first thought would be to simply use a low capacitance multiplexer, like...

I mean, several light years from here, is it possible to distinguish between the signals coming from Earth and the massive amount of electromagnetic radiation emitted by our Sun? From a great distance, every solar system must appear dot-like. Is it possible that civilizations are actually...

Homework Statement I have difficulty in understanding the meaning of fundamental cutsets.I don't really know how to find the fundamental cutsets.Can someone please guide me.It would be the best if there are any examples and links cited for me.Thanks in advance.. Homework Equations...

HI ALL Well i want to know the power electronics required to transmit signals for sensors,limit switches ,push buttons up to PLC, and if analog device signals like potentiometer could be transmit tted with these ,how can i do this . i am using Plastic Optical Fibre and please help me with the...

What is the point of repeating the TR 90 degree pulse in MRI? I understand you must modify the TR time to get different T1 times, but since the echo signal is read, would'nt all the echo signals be read to the same intensity after a 90 degree pulse?

Question one Homework Statement x[n] = 5sin(0.22*pi) The root mean square (RMS) value eof a sin wave is known to be A/root(2) where A is the amplitude. If the noise in a system is known to have an RMS value of 0.5, what si the signal to noise ration (in dB) of the x[n] in this syetem...

Homework Statement Consider two signals gl(t) and g2(t). These two signals are delayed by amounts equal to tl and t2 seconds respectively. Show that the time delays are additive in convolving the pair of delayed signals, whereas they are subtractive in crosscorrelating them. Explain with...

Homework Statement Determine the Fundamental Period and Frequency I got this question wrong on My midterm and I was wondering if you guys could give me some feedback on it x(t) = cos[50(pi)t] + sin[15(pi)t] Homework Equations T(fundamental Period) = 2(pi)/w // w is the frequency...

what is the bandwidth of single tone signals? taking the F.T. for a cosine signal gives a delta at the signal's frequency, so does it mean that its bandwidth is zero since it is occupying only a single freq. in the FD.