Signal Definition and 935 Threads

I had a thought-experiment I was pondering the other day. If you could somehow isolate a single atom inside a vacuum inside a Faraday cage, how would that atom behave in terms of translational movement?

Hi everyone, I want to understand how these concepts work. Suppose that we have a signal x(t) which has a maximum frequency component of 3 Hz. So let the DTFT of this signal be like that: http://img341.imageshack.us/img341/1134/31096081.png Also let y[n] be the digital signal that we get...

So I was playing in MATLAB with signals. I recorded myself saying some sample sentence. I imported it as a vector (it was mono), and reproduced it and it worked. But then I told matlab, to skip every other element. Basically I wrote this: soundsc(a(1:2:end),44100). what I EXPECTED was to...

Question: What signal (voltage or otherwise) vs time displays do you have in your house? Answer? I am a little confused as to what exactly this question is asking. My initial suspicions say that a TV because they receive a signal over time and display that as picture on the screen. Also I...

Im having a little trouble about how to go about defining this signal. It has a sqrt(-1) in it raised to a power so this is where i get confused. No doubt my poor algebra skills may be holding me back from understanding this problem. The signal is x(k)=j^-k u(k) I need to determine: A...

Hi, I'm doing ICT (telecommunications) engineering and have enjoyed subjects which involved signal theory (using matlab, Fourier transform, modulation, filters etc). Just wondering if there is a job where I can use the theory/maths that I learned in these subjects?

I have a project where I'm trying to take a variable frequency input signal and converting it to a fixed frequency, variable duty cycle output signal. The input signal is a sin wave ranging from roughly 150Hz to 6kHz. The output signal needs to be fixed at 150Hz with a duty cycle range of...

Hi All, I am confused about what is meant in the mathematical definition for the energy of a signal. Why is it the integral of the magnitude of the signal squared? ∫(|f(t)|^2) How do I deal with the absolute value sign? I do not have much experience with absolute value signs in...

Homework Statement A signal goes through a black box and out comes another signal. Now I have the signal that came out and need to find the signal that went into the black box. This by analyzing a test signal and the output of that test signal. The analysis is done in the frequency domain...

I have tablet phone samsung galaxy tab... when I check the signal strength, it shows -82 dbm... I thought it is produced by the Signal PA (Power Amplifier) on the PCB... According to what I know, the signal from the handphone is so weak to reach the nearest terrestrial station on the...

hello I am in the final year of my electronics engineering technology program and I've really developed an interest in subjects such as analog and digital signal processing, filters, amplifiers, etc. are there jobs in these areas for people at my level? I've been doing some job searching and...

So I have a signal X, consider it like a signal from an axis of an accelerometer. This signal is a simple array: X = [ 200.2, 198.1, 197.2, 195.4, ... ] The problem I have is that the same movement, imagine a circle or something like that that user does can be done fast or slow (but its the...

Im taking This class EEL3135 and I am very lost and confused as to how to study or where to find resources to understand the material. does anybody know of a good website for beginner signal analysis? or a good reference ebook etc to help me out with it? the ones i seen are far too advanced...

Hello, I have some 10 signals in noisy and nonoise(noisy+good) situations. I just calculated the power of each signal in two cases and then used SNR formula for dB(10log noisy/nonoise). Now, I got noise levels in dB's. Here, i confused that these dB levels are referred to...

Hello, I have built an AM transmitter and now I can only receive signal within just 1m radius of the transmitter. I use a colpitt oscillator to get a carrier of 740khz. For the modulating signal I'm using a 1khz tone from a signal generator although I've also used an electret microphone. I am...

Hi there, I'm taking some measurements of a wireless signal using InSSIDer 2.0. Sometimes the signal fluctuation is upwards of 20 dBs, and sometimes the fluctuation is almost nothing. It is a very short range signal. There is minimal fluctuation in the signal shown when I'm 10 metres...

[SIZE="6"]Name 5 signals and the systems that process them. – Draw the block diagrams to show how the signal gets transformed. • Choose both Continuous and Discrete signal • Include some examples from Bio Medical Engineering.

Hi, I am new to signal theory and don't know what is time domaine signal and frequency domaine signal. Please some can explaine me clearly and how can we convert between those two domaines. I read the topic in wikipedia which makes me somepart clear but interested to know...

does bjt amplify dc signal? why or why not?

This may seem like a naive question to some people. I had always heard that Lqg can easily incorporate supersymmetry---that if there were any evidence of it, putting it into the theory would be straightforward. This goes way back, to papers I read in 2003-2005. Not sure exactly which, but it...

Homework Statement x(t) is input into a perfect lowpass filter with frequency response H(ω), having a bandwidth of BHz and a passband gain of 1. For B = (2πT)-1 Hz, calculate the ratio of the output signal energy to the input signal energy. Homework Equations x(t) = Ae-|t|/T The...

Homework Statement Describe how the concept of wave superimposition is used to create AM radio waves. Homework Equations The Attempt at a Solution O.K, I am not sure that I understand how this works. In the picture attached it shows the carrier frequency inside of the audio...

Hello folks, I am an out-of-my-depths biologist looking for some guidance. I have a reference signal and 2 other signals. Signal 1 independently measures the same event as signal ref but signal 1 generally underestimates signal ref. Signal 2 is measured the same way as signal 1 but but it...

When I put an o-scope probe into my (120VAC) wall socket, with no ground (reference) attached, just a single wire, I get a perfect 60 Hz sine wave, with about 35Vrms magnitude. When I plug the o-scope probe into the socket with the ground attached appropriately to the return of the same...

Hey, all. I've run into a real problem with my control circuit. The circuit is simple enough. I am designing a controller for a servovalve that looks something like this.The frustrating thing is, it works in one direction, but when I flip the switch to reverse polarity, it stops working...

i have a signal y(t).I have sampled my signal at T0,so i got y(nT0).I multiply this signal with a random number r uniformly distributed in the range 0.95-1.05.Now z(t)=r*y(nT0).How to get z(t) mathematically?

Homework Statement Solvinf the unit time step equation mathematically. Homework Equations x(t) = u(t+1) - 2u(t) + u(t-1) The Attempt at a Solution How can i solve this signal mathemtically :( and using plotted signals , i couldn't understand, here is my approach and I'm...

Considering the ADF (automatic direction finding) of an aircraft. Assuming the transmitting aerial is vertically polarised i.e mag field lies in the horizontal plane. And it is the magnetic field of the incoming signal that induces current in the loop. And what would be the rotating plane of...

it seems like a pretty commonly used computational/mathematical method in analyzing experimental data, such as voltage signals

How many out there have hearing problems? Can you suggest a way to add heads up display to a noisy sports car? Old sports car I am constructing uses one light bulb [on each side, at the rear] to indicate 1. turnsignal 2. braking 3. nighttime driving. I figure, if I can create a separated...

I recently simulated a parallel resonant tank circuit on multisim. I put an oscope across the tank circuit and I get an AC signal, but what interests me is that it is amplitude modulated. The oscillations slowly build up in amplitude, hit a peak and then die back down. I think that the...

How do I determine what percentage of a signal is reflected and what percentage goes through a wall. I know that I am over simplifying things, but for the purpose of my project I need a simple answer to this problem. What parameters are needed for the solution and how do we calculate this...

Hi everyone I really don't know how to start this questions, please help me. Thank you in advance for all your help & support. Determine if each of the following CT signals is periodic. If periodic find it period. a) x(t)=2sin(10$$\pi$$t-30degrees) b) x(t) = 2 cos ($$\sqrt$$2$$\pi$$t)...

Homework Statement Suppose we are given the following information about a continuous-time periodic signal with period 3 and Fourier coefficients a_{k} 1. a_{k} = a_{k+2} 2. a_{k} = a_{-k} 3. \int_{-0.5}^{0.5}x(t)dt = 1 4. \int_{0.5}^{1.5}x(t)dt = 2 Determine x(t) Homework Equations if x(t)...

hey there.. i just don't know how to start answering this question.. please help me get through this question.. thanks.. A channel has amplitude response and phase shift shown in the link below. State what type of distortion is imposed for each of the inputs given below: i) (cos 20 pi t) +...

Hi guys, I'm a bit embarassed that my first post here is in this section, but I'm taking a Elec. Eng. course abroad, which is out of my confort zone (i'm majoring in automotive eng.) and I'm trying to solve a few model problems. This one in particular deals with the DFT. Anyway:Homework...

I am using an FFT package (GFT) to analyze a signal from a pressure sensor. I am unsure of the results I am getting, so I decided to try to verify the FFT package using a known input. I am using a signal generator to produce a sine wave of +/- 5V @ 5 and 100 Hz. When I run the FFT on the...

Hi, I have trouble understanding these concepts http://cnx.org/content/m10055/latest/ if I understand is correctly, the energy is basically a number telling us how "big" a signal is while the power, is used for signals that don't decay, thus give us a infinite amount of energy, but still we...

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...

Hello. I've made a lab experiment of interference and with a CCD camera photographed fringe pattern which one can understand as a periodic signal. My question is: When I apply an FFT to the image is there any limit to the amplitude information I may get from lower frequencies? I read in the...

I don't understand why cells have thousands of different receptors which then exert their effects through the same few intracellular pathways. For example, I know that many different neuromodulators which act through metabotropbic receptors exert their effects on cAMP, which then exerts effects...

Hey guys, first of all this is my first post in here so I hope I am doing the procedure of asking questions the right way. My problem is; I want to add two signals and generate a 1.5 period of sinusoidal wave only at the beginnig. It will be a sine wave starting at t=0 and ends at t=1.5T...

Homework Statement Consider the signal x(t)=cos(4t)+cos(5t)+cos(6t), and the SLIT with impulse response: h(t)=\begin{cases} 1, & \mbox{if } |t|<T \\ 0, & \mbox{if } |t|>T \end{cases} For what value of T is the output of the system y(t) equal to Acos(4t)+Bcos(5t), when x(t) is the...

Hello, Recently I've been very interested into going into signal processing. I have a couple questions... 1) Exactly how much math do you need? Do you need anything past PDE's? 2) How are job prospects for this field? 3) Are you required to do any hands-on stuff? (e.g. build...

Hi I have a practical problem/question: I need to wire 2 PLC-s for communications (RS485 signal) and I am planning to use shielded twisted pair cable (Cat5 FTP). The signal cables are quite short - approx. 6 m. One possible problem that could arise: between the 2 PLC-s, there is a...

I'm trying to plot the PSD of a signal, I did it using the fft function but I was wondering if there is another direct method?

If I know the: Frequency Effective Radiated Power Height Above Average Terrain Radiation Center Above Mean Sea Level Radiation Center Above Ground Level of a radio signal / tower, is there a way to determine the rough range of the radio signal?

Hi Does anyone know what a 2-wire dc polarity reversing voltage signal is? I have never heard of this type of signal before. I have gone insane trying to google it but to no avail. Any sort of help will be much appreciated.

When a signal from an accelerometer is being filtered should a high or low pass filter be used? I am trying to isolate a particular instance in which we suddenly stopped but I am not sure wether a high or low pass would isolate this.

First off let me just say that I am not a EE and have never taken a signals course before though I am sort of willingly having to over come this for a work project. I am working with a sensor that is giving me a noisy signal and I am trying to figure out if there is any usable data in my data...