Signal Definition and 989 Threads

To avoid busy waiting...we use block and wakeup functions in our definition of wait() and signal() but its mentioned in Galwin that still we have not been able to eliminate busy waiting completely... "we have just removed busy waiting from entry to the critical section...futhermore we have...

I took the FFT of a signal that was taken at non constant time period (T), but at a sampling frequency(Fs) of 6.5 hz. Can I take the FFT of a signal with non constant T, and does it mean anything? Please see attachment. Ps. I used Matlabs, FFT command, which i think uses the Cooley–Tukey FFT...

Homework Statement Given a sine wave signal (20V PP) connected to a 10 kilo-Ohm resistor. Calculate the current through the resistor in terms of average, rms, and peak currents. What wattage rating should the resistor have? Homework Equations Vrms=(1/Sqrt(2))(Vp) V=IR The Attempt...

I have m(t)=0.2sin(w1*t) + 0.5cos(w2*t) ---> Note: the 1 and 2 besides "w" (omega) is not a coefficient, its a subscript to show that they are different. I found the Fourier transform to be M(F)=0.25[∂(f-f2)+∂(f+f2)] + 0.1j[∂(f+f1)-∂(f-f1)]. My question is, how do I sketch the magnitude...

I have found a circuit that uses a BAS16 small signal diode to level shift a 5V (or 3.3V) TTL signal down to a 1.8V TTL signal. The cathode of the diode is on the high voltage side and the anode is on the low voltage side, so it looks like it is backwards compared to the direction of current...

hi... after amplification of a signal through an amplifier, the amplified signal is 180 degrees out of phase with input..why?? thanks..

Hello everyone! I have a system with 2 lasers and a single camera. I have two trigger inputs going to each laser, they have a delay of minimum 350ms. These triggers are split and need to be connected to the camera to open it whenever the lasers fire. So i thought of a Tee junction where i...

I have the readings from a signal in a file (floating point values) that I wish to apply the Fourier Transform to. The samples (mV) were taken every 4 milliseconds and I wish to transform them into the frequency domain. How would I apply the FT to a set of values without knowing any...

Hello all, I'm an electrical engineering tech student working on a little side project and I can't find anything to help me with a crucial part. I have a gauge cluster out of an automobile that I want to interface with a computer to used while playing a racing game. I have a computer...

While studying the type of signal propogation in telephone wires, I read that it has a bandwidth of 400-3000 Hz and the signal travels with the speed of light(as in case of all electric signals). So electronics at the two ends communicate atonce. One changes the voltage at one end and the other...

Suppose you have a source that send a very strong straight beam of light (say laser ) Then you direct the light toward a distant wall with angle 45 degree as show in the drawing below Then if you rotate the source 90 degree in one second, what is the velocity of the visual effect (spot)on...

I've got a signal coming that can theoretically reach a maximum of 400V and at around 5A. This is not an AC signal, it's DC. However, I need to attenuate this signal down to a maximum of +- 10V. What steps do I need to take? How do I go about this? How to minimize loss of signal clarity?

Hello to everyone :) Since I did not notice a presentation section I put some info about myself before the question,. My name is Enrico, I am Italian (form Modena) and I am 18. I am studying Electronics&Telecommunications in High School and I have applied for UCSD/UCLA/Berkeley (I hope they...

Computationalism has a number of inconsistencies that haven’t logically been refuted. The purpose of this thread is to discuss one of them and see if there’s a way out of the problem and/or to help get perspectives on the problem. That problem I’ll call the “special signal problem”. In the...

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) =...

Hello, Can you suggest me some good Math books about Fourier laplace transforms, convolution, transfert functions and stuff ? Because all I have right now is some crapy math notes and an electricity book that doesn't mention anything about math theory. I tried google but I really don't...

I am trying to get an understanding of what a good signal to noise ratio in terms of decibels. My SNR is roughly 20 dB, and am concerned about being able to resolve the signal from this.

Hi All! I has probe (B-field induction probe) with non linear amplitude-frequency characteristic. I has calibration table with 3 columns: frequency, amplitude, phase. I has output signal U(t) recorded with sample frequency Fs during rather long time. Can I restore input signal (i.e. B-field...

Mathematica problem: Filter: H(jw)=(3.84+5 (j w))/(5+j (1.11 w^2)) Bandwidth where: |H|>1/Sqrt[2]*Hmax Calculate the bandwidht Tips or solution would be much appriciated Thanks

I'm not an engineer and so I appreciate everyone who contributes. 1)Is there any measurable cell phone interference from a car battery, alternator, or starter while the car engine is running if the cell phone is in the driver's seat? 2)What would this interference look like? Thank you.

Hey Guys, Im currently designing a primitive audio mixer unit using opamp circuits for simple filters/crossover networks. Prior to the signal being run through a power amp circuit I am looking to pass the signal to an ATmega328 MCU which has an ADC with a range from 0 to 5 Volts outputting to...

Hello, I'd like to know the relation between the sampling frequency and the quantization. If the sampling frequency is 200KHz, and the analog signal ahs a maximum frequency of 80KHz, How many bits will the qantization be done to have a 6Mb/s bitrate?

Hello everyone, My colleague and I are transmitting serial data over a visible light communication channel. How can we eliminate flicker? - i.e. when the signal is 01000100 the LED is dimmer than 01111011. When long strings of data are sent, it causes the LED to flash and it's detectable to...

letsa say i have an ak = cos ( k*Pi/4) + sin(3*k*Pi/4), the signal is discrete time, fundamental period N=12. the way i would derive its x[n] is.. Sum(k=0, to 11 of: 0.5*exp(j*k*Pi/4) *exp(j*k*w*n) + 0.5*exp(-j*k*Pi/4) *exp(j*k*w*n) + (1/2*j)*exp(j*k*3*Pi/4) *exp(j*k*w*n) -...

hello, i have a signal current I(t)=Acos(wt+theta) How can i calculate the signal power and noise power individually? thanks Reza

Hello everybody. I'm appologizing for a lame question, but taking for example A*cos(w*t) (whose spectrum is two impulses each of 0.5A in magnitude)-his power is 0.5A^2. It can be interpreted as a sum of squared magnitudes of its impulses. So, if I have a signal which consists of impulses...

I've been working on a guitar effects project for a while and I need a little help. What I want to do is add even harmonics to the signal. The way I've gone about it is this: I've used a diode to add harmonics to the signal. At very low volatages (<1v) the diode current may be approximated as...

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!

Hello! This is my first post here! :) I was just wondering, after experimenting with an indoor TV aerial, Wrapping Tin foil around the base, ensuring contact with the main metal conductor, I found that it improves the signal by around 5 times! (Positioned correctly of course). I was just...

Homework Statement If you had a function generator that generated wave forms so you could veiw them on a computer screen and it was showing a square wave with and input signal of 1V (amplituded 0.5 V) What would it look like if the signal was reduced by 10 dB. not sure what to do with...

I had posted a thread on another forum about building a 100GHz oscilloscope which resulted in the signal being chopped up by a bank of comparators and subsequently being fed into a video buffer for processing using currently developed parallel processing techniques. The subject of compression...

I was solving this problem, and I was comparing my answers with a classmate, and we got very different answers. I don't think I made a mistake here, but I may have missed something. Homework Statement Tipler - Modern Physics 5e 1-57. "Two observers agree to test time dilation. They use...

Homework Statement x(t) = u(t) - 2*u(t-2) + u(t-5) h(t) = exp(2*t) * u(1-t) Homework Equations Need to find convolution integrals for all possible intervals The Attempt at a Solution Ok, the first thing to do is to rewrite these equations in terms of \tau. Now i have: x(\tau) =...

The signal x(t) = e^{jt} is periodic. The signal x(t) = e^{-t}e^{jt} is not periodic. The decaying exponential makes the complex exponential decay and converge toward zero, but why is it not periodic? Also, this signal is not considered time limited since it never actually reaches zero...

Homework Statement What is the bandwidth of an AM signal if the modulating signal is x(t)=cos(2pi70t)+cos(2pi90t) and the carrier frequency is 10kHz? Homework Equations The Attempt at a Solution The carrier frequency is irrelevant because it just means the signal's spectrum is...

would it be possible in theory to take an audio signal, do an Fourier transform on it, divide all the frequencies by 10, convert it back to the time domain, transmit the resulting signal over 1/10th the bandwidth you would have originally needed, then reverse the process on the other end...

Am getting actually puzzled about some facts from telecommunication. When signal are transmitted from two mobile phones, the signal which is converted at the sending end from analogue by the speaker into digital on the mobile phone, does the transmitted signal actually wirelessly i mean is in...

Homework Statement If the received signal level for a particular digital system is -151dBw and the receiver system effective noise temperatyre is 1500K, what is E_b/N_o for a link transmitting 2400bps? solution says: (Eb/N0) = –151 dBW – 10 log 2400 – 10 log 1500 + 228.6 dBW = 12 dBW My...

Homework Statement 1. i need to obtain the result of x[n] * x[n] (convolution) where x[n] = δ[n] + δ[n-1] 2. I need to obtain the power of the signal x(t) = 4 cos (ω0t) + 2 sin (ω0t) + 2cos(4ω0t) for R = 1 k Ω Homework Equations 1.Who do you convolute 2 diracs ? 2. what is the correct...

Homework Statement The problem is to sketch the signal over time: x(t)=1+δ(t-2)+δ(t+2)+δ(5) Homework Equations N/A The Attempt at a Solution I'm not too sure how to begin this. Would it look like a square wave with different "peaks" over time?

I'm setting out on a project, and I need some basic direction. I am a programmer by trade; my father is a mechanical engineer who is pretty good at electrical circuit design as well---together we want to control a pipe organ by computer. The organ is already operated by electrical solenoids...

I'm utterly confused about this concept and the textbook quite efficiently confuses me further. I'll just try to explain it with an example: The circuit has a V(cc) = 10 V and V(ee) = -10 V. V(c) = 2 V, V(e) = -1.7 V, V(b) = -1 V, I(c) = 1 mA, I(e) = 1 mA. It says that allowable signal...

A discrete-time signal x[n] is filtered through a PAM p(t). The shapes of these signals are described in the attached image. i) Calculate and plot the output y(t) from this pulse amplitude modulation. ii) Let y[n])=y(nTs) be the sampled signal of y(t). Calculate and plot y[n] iii) Determine a...

I was trying to use the Ortec Aspec-927 MCA with Maestro-32, and realized the PMT signal is too weak for it to detect. I passed the signal through a 16-channel amplifier, yet it is still not detecting anything. I passed the output from the PMT into an oscilloscope, and the PMT is working just...

Homework Statement x(t) = e(-2t) * u(t) Ex = x2(t) dt Attached is the work I have done. Got stuck towards the end.

Homework Statement Sketch the signal: x(t) = 2^(-t*u(t)) over (-1 < t < 1) The Attempt at a Solution Attached is an excel fine with my work out. I want to know is it is correct.

Suppose you design the digital circuit with D-flops and need to deal with asynchronous signals. Typical logic is receiving the async signal with a D flop followed by another D flop to deal with metastability. But how does double flopping benefit against the metastability ? The first flop gets...

(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 read in several places that monochromatic light cannot convey information; e.g. in http://www.mathpages.com/home/kmath210/kmath210.htm. it is stated that "in order to actually convey information, a signal cannot be a simple periodic wave". But doesn't all light have the energy hf? And...