Signals Definition and 434 Threads

Do receivers only receive signals or they emit emf?

I am an electrical engineer, and I know that my question is not directly relevant to the pure Physics but anyway, my question is that how electric signals move inside wires? how to initiate the electrical signals knowing that in order for the electron to move in a circuit, we need a continuous...

Homework Statement July 22,2017. Homework Statement Television and radio waves can reflect from nearby mountains or from airplanes. Such relfections can interfere with the direct signal from the station. a. Determine what kind of interference will occur when 75-MHz television signals arrive at...

I need to calculate the composite power at the input of an RF distribution system, is it just the sum of the signals in milliwatts at the input? I can measure each individual signal with an a spectrum analyser but I do not have a power meter to anable measurement of the total power.

Homework Statement continuous time LTI system is given with differential equation y'(t) + 5y(t) = 10u(t) a) Find transfer function of system and determine is it stable or not. b)Find frequency characteristics (amplitude and phase angle) of given system c) Find impulse response using Laplace...

Hello everyone. Iam trying to get my head around the difference between real and complex numbers, but Iam having a hard time... I read that the difference is that a complex signal contains phase information. If I look at a real signal --> x(t) = Acos(wt + Θ) and compare...

I have 2 rubidium clocks which both are generating 10MHz sine wave. Some reason my system is giving bad data. So, I am deciding to inspect every single part of the system. I am trying to check the rubidium clock and make sure it have to be in nanosecond time variation, because: t=1/f = 1/10e6 =...

Hello All, Is it possible to analyze signals/photons/pulses from a 57Co source (strength 2 microCi) using a ADC (multihit readout) with 5 GS/sec? Just to look at pulse height spectrum..also I am interested to make a coincidence counting between 122 adn 14.4 keV levels! I heared that these ADCs...

Can we send a quantum linked signal into space and be able to tell immediately whether or not it is ever observed?

Homework Statement [/B] How are we able to go from the first line to the second line and then the second line to the third? Homework Equations Euler Identity: e^j(theta) = cos(theta) +jsin(theta) The Attempt at a Solution This problem is more about preliminary theory in my opinion so I tried...

so, continuous signals as sums of weighted delta functions can be represented like this: if you switch order of some variables you get ∫x(τ)δ(-τ+t)dτ, and since,I presume, Dirac delta "function" is even I can write it like this ∫x(τ)δ(-(-τ+t))dτ=∫x(τ)δ(τ-t)dτ=x(t) and we got ourselves a...

in terms of calculating energy and power, why don't we use absolute value of signal and then integrate it from -inf to +inf instead of squaring it and then integrating it over -inf to +inf? for example ∫|sinx|dx (from -inf to +inf) will give you, relatively speaking, the same answer as...

Homework Statement [/B]Homework Equations i(t)=5u(t)+ 3u(t^2)The Attempt at a Solution

Homework Statement Find the closed form of the impulse response of the system y[n] = 7y[n-1]-12y[n-2]+x[n] using the peel away and guess method. Ie, by using Python code to find the geometric ratios and amplitudes of the outputs as n grows large, then calculate residuals, and find the...

So there's a spaceship 5 light years away from Earth and they want to send a signal to Earth but a cloud of interestellar dust don't let them use light or radio signals so they decide to send a gravity signal. So they produce a violent huge thermonuclear explosion that will send some particles...

Hi I have a question about current start signals in a simple circuit such as explained in http://amasci.com/elect/poynt/poynt.html. Turning on a switch somewhere in the circuit, sphere of influences, i.e. motions of electrons in wire and generation of Poynting vector around the wire, start from...

Hello everyone, I am interested in analyzing sounds (both spectral plots and time plot). What type of hardware would I need? There are a lot of free softwares online... Are there educational hardware tools that are not too expensive? thanks!

If i have two sinusoidal ac signals of 220V with the different phase angle i.e. there is some phase difference between them. Then can i make the phase difference zero?? Please tell

i just had my first Signals processing Lecture, during AM modulation part my prof said that: V_AM(t) = (V_main(t) + 1) * V_Carrier while V_Carrier = sin (omega * t) 1-is there a proof that we get the envelop of a function by adding one then multiplying by some trig value? 2- what's the...

How are transistors able to amplify full AC signals? What I mean is that a transistor will conduct only if the base emitter junction is forward biased and when you apply high enough treshold voltage to turn it on. Like 0,6v. Then looking at the graph above, from 0 to 120 and from 120 to 0v the...

Homework Statement I obtain Autocorrelation function of two signal: as Homework Equations [/B]The Attempt at a Solution [/B] I want to know what is Normalized Autocorrelation of above equation? Thanks

Hello, PF! I've been learning some process control on my own lately, and some questions have come to my head while on it. Consider the following on-off control loop: Let's say we want to control the temperature of the fluid inside the tank. We set up an on-off control loop and establish a...

I would like to improve my knowledge of signals. I just came across this topic while reading a book. So I would like to know how to find out that the given signal is power signal or energy signal. For example please solve the following and give your explanation in reference to that. e^j(2t+π/4)

Hey guys! This is my first day on the forum so, hey! I'm a third year electrical engineering student and I'm really having some trouble with Signals and Systems so I want to know what helped other people understand it so that maybe I could try some of their methods. What were your biggest...

I understand what is Monochromatic frequency signals from https://www.physicsforums.com/threads/monochromatic-waves.570958/, but could somebody kindly give a brief explanation about "why does a monochromatic frequency signal result in poor PAPR (Peak to average Power Ratio) performance"...

Hello everybody, I'm a little bit confused about two types of amplitude modulation. We distinguish here: Case I : Amplitude Modulation with suppressed carrier (https://en.wikipedia.org/wiki/Double-sideband_suppressed-carrier_transmission): Case II : Amplitude modulation with carrier: Now...

So many people walk while looking down at their cellphones that a couple of German cities have started embedding traffic signals in the pavement at crosswalks. German city puts traffic lights on the ground -- for you phone gazers (CNN)

Not sure if this is the right section or if this might be better off over at Cosmology... or...? So this is actually around a story concept I had, and while I would like to get the science as right as possible, I expect a certain amount of hand-waving to get past some of the difficult and...

I have two systems that are approx. 300-400ft apart that I am connecting via a 10 Gig fiber connection. The fiber I am using is a 100um core MM fiber and the switches will be using a 50um core OM4 (4700 MHz*km) SFP module. Is there a way to find out what type of loss I should be expecting, is...

This question is a little basic but.. how are signals stored in a Fourier Transform function f(t)? In my PDE class we were always given a base function to put in terms of sin and cos. But when taking a bunch of samples, all I end up with is a table/array over some time T. How might I use this...

In my electrical engineering Textbook, In the beginning of it, when they were introducing analog and digit signals, they said an analog signal was a signal that depends on some sort of changing continuous variable such as time. The later went on to say that Analog signals can be depending on...

How many NMR signals and peaks will there be for a di-substituted benzene ring and why? The ring has one CH3 and and a Cl ortho to the CH3. (This isn't a homework problem but I am running into same issue whenever I encounter rings wrt NMR) i am specifically confused as to how to apply...

Hi there, why the decomposition of periodic Composite signal give discrete frequencies and decomposition of aperiodic signal give continuous(in decimal) frequencies. please kindly do explain the concept behind in as simple words possible. Thanks

Can someone kindly explain , what is the frequency of non periodic signals? Periodic signals have frequency of number of cycles completed in one second and but non periodic signals don't have repeated pattern so what would be the frequency of non periodic signals. Kindly do explain it in simple...

Does all the signals detected by He-3 detector caused by neutrons? When the He(n,p)t reaction occurs, will proton cause any secondary x-ray photons since it de-accelerates in matter.

I've recently got back to writing more of my SF novel (after a lengthy interval) and picking up the threads again, I find myself instantly confounded by a problem that has been waiting for me all this time: detecting spacecraft at a distance - by which I mean distances counted in dozens of AU...

Hi all, On a vehicle I recorded an output signal that is positive and it's variability is lead to the 30 input signals, but not all together at the same insant. Just by checking the pairwise correlation between signals in a time periond, I'm able to detect which input signals lead to the...

Hi all, Building a frequency offset locking circuit for laser spectroscopy. First electronics project so been hitting a steep learning curve. Long story short, I have two branches in this circuit that take a AC signal run it through a diode and low pass filter to measure the envelope and output...

Hi All, I am a EE student and thinking about doing the following classes in Spring 16 - Signals & Systems + Electromagnetic + Physics 3. Any suggestions is Emag and Signal and systems very hard?, what Math do you need? (Dif Eq) Is it a bad a idea taking these classes at the same time...

Why exactly do electrical engineers represent sinusoidal signals with the frequency in terms of radians/sec but phase shift in terms of degrees? Why don't we represent the phase shift in radians? I'm curious where/why this convention originated.

Are all real life signals infinitely continuous and differentiable? I'm thinking yes because a finite discontinuity in one of the derivatives would imply infinite to take place in the next higher-order derivative. And infinite means infinite energy.

I have two signals (time series) shown in the plot below. Just by looking at the figure, we can see that the two main peaks of both signals are very closely aligned (correlated), however the red signal has additional features elsewhere which don't match the blue curve. I am looking for some...

Homework Statement In this book of mine , I saw this statement,"The digital-system designer is restricted to the use of binary signals because of the lower reliabilty of many-valued electronic circuits." . Why is so? How can we say that the many-valued electronic circuits are not reliable...

Homework Statement Good Day, On an oscilloscope, when two incoming signals are out of phase, in an XY setting, an ellipse appears on the oscilloscope screen. The phase shift between the two incoming signals can be found by the formula: sin^{-1}((Y_{max})/(Y_{int})) where Y max is the...

Thank you all for helping. Today I have another question: If individual charges move at around (10^ -4) m/s, then how come signals are being able to travel at great speeds- like approaching speed of light? Isn't it too fast?

Hello Forum, I know a little bit about how the oscilloscope works: an electron beam hits the scope screen and traces the waveform. Once the beam reaches the right side of the screen it zaps back to start tracing again. Is it possible that while the beam returns to the lefthand side of the...

Dear everyone, I am thinking about what know of machines in RF lab can catch heart beat signal, In the RF lab with spectrum and network analyzers, also have Function generator and more. They are just working on signal with high frequencies, but heart beats are very low frequencies about...

I have managed to work out parts a and b of Exercise 13.7 from MTW (attached), but can't see how part c works. I can see how it could work in (say) the example of taking a radar measurement of the distance to Venus, where we have the Euclidian distance prediction and the result of the radar...

Hi all, I am working with some data which is a combination of gamma ray signals and some other gamma ray background. Someone told me that I can use Poisson distribution to separate the data from the background but I am not sure how. Does anyone know how to use Poisson or any other viable method?

Homework Statement Find the impulse response for the systems governed by the following equations: 3y(t)'+5y(t)=x(t)+x(t)'[/B]Homework EquationsThe Attempt at a Solution I tried to obtain the homogeneous solution for h(t)[/B] and then I failed to obtain the coefficients of the solution