Signals Definition and 410 Threads

Hi, newby here, hope I can get some help on this question. I have a project that requires me to use a standard 9 LED torch head, normally running on 4.5 volts (three AA batteries) My project needs me to use 12 volt batteries to supply a control box and finally the 'torch heads' a distance away...

I have been going through the ac signals coupled by a capacitor to a dc network.. Using superposition principle.. for solution it was shown that both bulk resistance and dynamic resistances for the diodes used are required... Why is this happening.. Since to what i know bulk resistance is...

Hey guys, I have a butterworth high-pass filter, and I was asked to find it's temporal response equation to the u(t) function. That part was easy, using basic Laplace tables I was able to find the following equation: y(t)=√2 e^(-31100t) *cos⁡(31000t+π/4)u(t) However, I'm supposed to be able to...

Hi On page 11 of this book, http://books.google.dk/books?id=Wv2OIC_SaDUC&printsec=frontcover&hl=da#v=onepage&q&f=false, it is stated that: "The phase modulation has an additional advantage: The first two sidebands at frequencies ω+Ω and ω-Ω have equal amplitudes, but opposite phases. A lock-in...

Alright, here is what I'm coming up with: we all know that most IR remote, if not all IR remotes works by the "lights on/lights-off" "principle", be the actual implementation “measuring” interval or space between 2 "ons" (or two offs), or demodulating one consistent on (or off) for a specific...

Hello. I have problem approaching the attached question and understanding how to solve it. I desperately need some help here. :confused: Thanks! :smile:

Hi All, Always wondered a few things about radio transmission, hoping to get some questions answered. 1. Is there a reason why certain frequencies are free to use by everyone and certain ones are reserved? Is it something to do with the fact that the cost (or means) to send signals on...

Hi folks, I'm currently a freshman at Memorial University of Newfoundland, in the science program studying Biology at the moment. However, I have recently began getting the crap kicked out of me in Biology by a 4th year Bio prof who has come down to 1st year apparently to sort people out, and...

Hello Forum, if we are trying to display a periodic signal (sine, square wave, triangular wave, etc...) on the oscilloscope we can use the trigger function: once the electron beam goes across the screen it returns back to the left side and starts "drawing again". 1) Does the electron beam...

Such as... http://img442.imageshack.us/img442/1999/image201202080002.jpg

I am a bit confused. http://pokit.org/get/bedc0ac7e1d17e01d7d58b021b81663c.jpg The function is y=x(2t) and the point of it is to show the property of time-invariance.(which we should fail in this example, because it isn't time invariant.) Input signal is x1(t) Output signal is shown for...

Hi everyone I have been in declining health since 1994. I was reading a newspaper about the smart meters BC Hydro is trying to force on us. The outright lies told about these smart meters and the real footprint they create, strong enough to kill rose bushes. Worse still, apartments will...

Uh... what do I say now? Do I repeat it, like a dolt? Why do pedestrian crossing signals count down then the traffic light stays green?

Problem: I have a sensor monitoring a process which is controlled by a feedback controller. This sensor fails from time-to-time and I need to replace it with a new one. I have always used the same type of sensor, say type A. Some sensor manufacturers are offering me an alternative sensor...

Hi In my notes I came across the following sentences:- Any signal consisting of the system's characteristic mode is sustained by the system on its own. The system offers no obstacle to this signal. Not getting what it means. Please, a little help needed. :-) Thanks salil

I am an Electrical Engineering.I want to ask that how different signals move in a cable without effecting each other..e.g interference etc.. I am not strictly speaking about it interfence but how at the end we can differentiate these signals and get one of our need.

Hi, I have a general question regarding the computation of Fourier Series coefficients for real and odd inputs. In this case, the following should be true: ∫x(t)*e^(-j*k*w*t)dt = ∫x(t)*sin(k*w*t)dt However, every time I compute my coefficients this way, I get the inverse sign of what it...

Hello PF, I have trouble understanding these 2 types of signals. I mean definition is clear, math is also mostly clear, but intuition isn't. Can somebody explain to me, why signals that have finite energy have 0 average power. Physical explanation if you may. I learned that average...

So I am 2nd year now and we started this new course Theory of Signals. Already I bumped into a wall when it came to understand basic stuff. Here is what I mean [PLAIN]http://pokit.org/get/0864633c869b647116b980428a07d4f1.jpg Here we have 4 functions, each representing one type of...

for one section of my project, i need to know the phase difference between two signal. they are both 40MHz, but out of phase by a certain angle. i have a AD8333 board from Analog Devices, it is a dual I/Q demodulator consist of double-balanced gilbert cell mixers. The board has 2 RF inputs, a...

Hi, I am currently working on a little science project, I came across this page about sending audio signals through a laser pointer. http://www.i-hacked.com/content/view/162/44/ I was wondering if it is possible if I did it with an ordinary light bulb. It said that the data is...

when we have x(-t) and we time shift it say x(-t-2) it shifts toward the -ve t axis.. where as x(t-2) the function is shifted on the + axis..why is it so?? see when we say there are 2 functions x(t) and x(t-2) it means x(t-2) is delayed by 2 sec with respect to x(t) therefore it shifts in the...

1)-why is x(t)+x(-t) always even??..no matter if x(t) even or odd? 2)-when we talk about unit step function...u(t)..and we add..u(t)+u(-t)..the value of both is 1 at t=0..so does'n't that gets added twice??..and it becomes 2 at t=0... 3)when we have x(-t) and we time shift it say x(-t-3)...

Homework Statement Hi suppose you're given two signals for example x_{1}(t) = cos(3 \omega_{0} t) x_{2}(t) = cos(7 \omega_{0} t) and you want to find out the inner product Homework Equations The Attempt at a Solution I mean, it's an integral right? But what will the boundaries be...

Hello, I am an undergraduate student and I am doing some data/signal analysis using the Time Frequency Toolbox for MATLAB (http://tftb.nongnu.org/). Specifically, I am using the Wigner-Ville Distribution (henceforth known as "WVD," as implemented in the tfrwv.m function in TFTB). Basically...

Hey guys, I was wondering if I could receive any help on a homework problem I have. I need to find the differential equation relating the input to the output. I've began working on it but feel like I've hit a brick wall in my work, any input? Homework Statement Attachment - Problem...

I have just had a very strange experience, and would like to know if there is an explanation for it. There was a small tin of black olives on my kitchen work surface. I put a teaspoon into the tin, to get an olive. The moment I did this, I heard what sounded like a radio broadcast of a...

i want to subtract photocurrents from two photodiodes. please tell me how to do this. also please tell me how to measure current and voltage with a lock in amplifier. Thank you very much

Just some background - I am trying to measure spurious radio signals around a carrier in dBc units. It seems easy until you consider the resoultion bandwidth you are going to set your specan up with. If you start with a large bandwidth the spurious signals can get mixed up with the carrier and...

Hypothetically, could the transmitter-receiver systems in cell phones communicate directly among other such systems at a range comparable to the range they can communicate with towers? With 4G bandwidth?

greetings, in case of signals we always deal with voltage why not current?

Homework Statement I have a trouble understanding what would be the output when for example we say let's input the signal x(k*n) or x(n-n0) to the system... this has given me problems when having to solve systems for which I have to check the property of time invariance suppose we have a...

Does anyone know what audio sampling signals? Not Audio sampling but Audio sampling signals Thanks.

Hi, I have a question and I was wondering whether you might help me, because I have done a lot of research nut no clues. Just bits and pieces. Thanks ALOT Homework Statement In digital transmission, what are audio sampling signals? What is the mimimum sampling rate required...

I have a set of discrete data that I have performed multiple Gaussian smoothing filters on to act as a low-pass filter. What I have come up with is something like this: http://i51.tinypic.com/152kieg.jpg I'm using findpeaks() in matlab, and a peak that I want is being taken over by the...

Anyone knows any good online lectures on Signals & Systems theory?

What is the condition for the continuous time signal x(t) to be periodic if it is the linear combination of n periodic signals. where x(t) = a_{1}x_{1}(t)+a_{2}x_{2}(t)+a_{3}x_{3}(t)+......a_{n}x_{n}(t) where x_{i}(t) is periodic with fundamental period T_{i} \forall i, where i \in...

hey I was just wondering if anyone can teach me how to graph a signal like this x[n] = { 1 for 0<=n<=4 { 0 elsewhere im not sure how to do this, what I have tried is x = [1 1 1 1] but this is not a function of 'n'.

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...

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...

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...