Signal Definition and 989 Threads

I'm a beginner at electronics, so please bear with me... I have a 3V signal that is triggered under a certain condition and stays on for less than a second (I have no control over this). This is connected to a DAQ that can only sample at very slow rates (Also, no control over this). I'm...

How to find the period of two signals added for example: if f= s1+s2 where s1 is a squre wave of (+ -) 1 A, period √6 secs and s2 is a square wave of (+ -) 1 A, period 1/√6 secs. Is this signal periodic if not why? Can anyone let me know about some link where I can learn all the examples...

Is there any recommended books for signal processing for self study? Or like a reference book covering most fields? my final bachelor year has been filled with prescribed papers but I'm thinking I will need to be familiar with signal processing. At the moment I am looking "Digital Signal...

I'm new to the field of signal processing and currently reading a paper which it uses cross-correlation of two signals for detecting some machine failures. But I'm confused with the complex conjugate in the equations. Take equation from wikipedia as example: (f\star g)(t)\equiv \int_{-\infty...

Hi, Does anyone have idea on how to determine signal frequency? I am a first year graduate student in biomedicine and previously studied some general engineering, not really very versed in mathematics. We have lots of data measured from human to analysis, including EEG, heart pulse and...

Hey, I'm an EE undergrad looking to tentatively specialize in signal processing. My relevant background includes a course in signals/systems, introductory feedback control (using Nise), analog communication systems (using Haykin), introductory probability, the usual Calc I-IV sequence, linear...

So this is a very simple question that I am having some trouble figuring out: Let s(t) be a finite energy signal with Fourier Transform S(w). Show that \lim_{w \to \infty } S(w) = 0 We know by defintion that the FT of this signal is \ints(t)e^{-jwt}dt and also that ∫|s(t)|2dt < ∞. I'm a...

Video Monitor Jack repair I have a Fahrenheit 7” LCD Wide Color Vision monitor that has a broken jack. From the monitor is only this female connector: Then there is a cable that goes from 8 pins to 24 pins (I count 12 on each half?): Next after that cable is the box, where the...

Homework Statement Given the following block diagram. Calculate the transfer function H(z) and find \theta (f=\frac{f_{s}}{6}) Homework Equations H(z)=\frac{Y(z)}{X(z)} The Attempt at a Solution Ok So I know i need to find my y(k) output equation from this. I can then rearange the...

Homework Statement You have two clock signals (one is 25/sec,other is 30/sec). Design a circuit that takes both clocks as inputs, determines the faster one within a second, and indicates faster one by lighting an led. The led should remain on until reset by a control signal. You may use...

In the digital communication class I took, people talk about how to do detection and processing at the baseband. But from what I read, it seems that many systems do the signal processing at some intermediate frequency without mixing it all the way back to baseband. My questions are why and how...

Hey guys, I got this problem. I have 9 fans motors in which i need to send a range of dc signal of 0-10 volts to each one. I had decided to buy a simple signal generator that can do the trick but soon realized that having one signal generator hook up to 9 motors at the same time will not be...

If someone in a distant stars is watching for signals of life coming from other planets, how far did the signal of life in Earth travel yet, in a cosmological context?

Hi, I have to detect overvoltage on each of the 3 phases (individually) of a 3 phase AC signal. The 3 phase AC source has a neutral that is grounded and I have to use the same ground plane for my PCB. I was thinking of using a full bridge rectifier for each of the 3 phase but the problem is...

Can someone explain the steps of this solution? In my linear systems class, we are doing Laplace transforms using transform tables and the properties. I can usually do the problems that closely resemble the table, but when they involve heavy algebraic manipulations, I don't know what to do...

Hi all; I am trying to amplify a dc signal using the AD524 amplifier . I connected the input- pin (pin 1) to the ground. pin 2(input+) to 0.5V (The 0.5 came from a varibale resistor). pin 3 (RG2) was connected to G=10 (pin 13). Ref.(pin 6) was connected to ground. Pin 7 (VS+) 9V. pin 8...

Hi There are several posts here on group velocity, phase velocity and the confusion caused by it. I also read that article posted on mathpages.com (who is the author ?). I have some questions after reading these things. Like that article says, there three kinds of 'speeds' concerning...

Homework Statement Observing a star with a telescope where a photomultiplier is applied, 5 photons per second are detected on the average. Assuming a Poissonian statistics and the the background is negligible, determine the integration time useful to measure the flux with a standard...

Hello, I'm not an electrical engineering student so please bare with me... anyways if let's say you swallow a pill containing a piezoelectric sensor to measure adsorption of a molecule in the stomach how can you detect the changes in frequency? if there is no "physical" electrical connections...

Hi, Is there any method(circuit) to retain only the positive frequency components of a signal? thanks in advance.

Homework Statement p[n]=x[n]w[n], where w[n] is the rectangular window. x[n]=\sum_{k=-∞}^{∞} δ[n-k] w[n]= 1, for -M≤n≤M; = 0 otherwise 1. What is X(e^{jw})? 2. What is P(e^{jw}) when... M=1? M=10? j is the imaginary number. (it's the same as i.) Homework Equations...

What method is usually used to locate exact place of radio signal source? Do exist some type of radio signals, exact place of origin which is completely impossible to locate?Well,at least up to few hundreds of feets?

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...

Homework Statement If a signal f1[n] begins in a moment N1 and ends in moment N2, and signal f2[n] begins in the moment M1, and ends in the moment M2, derive the formula which states in which moment begins and ends the signal f1[n]*f2[n] Homework Equations The Attempt at a Solution I...

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...

Homework Statement What is the amplitude of the spectroscopic signal if the inclination is 45 degrees? Mass star = 1 mass of sun = 1.9891 x 10^30kg Mass Planet = 10 mass Earth = 5.9736 x 10^25kg Orbital period = 1 year Homework Equations I'm not sure about even what equation to use. 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...

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 Let a system that converts a continuos-time signal to a discrete-time signal. The input x(t) is periodic with period of 0.1 second. The Fourier series coefficients of x(t) are X_k = \displaystyle\left(\frac{1}{2}\right)^{|k|}. The ideal lowpass filter H(\omega) is equal to 0...

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 I have trouble understanding what the components are suppose we have this discrete time signal x[n] = e^{j \frac{2\pi}{3} n} find the number of harmonic components Homework Equations The Attempt at a Solution in my book it says that we have a set of harmonically...

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...