Communications Definition and 69 Threads

A new paper published recently in the Nature Communications journal suggests the AMOC will go through a tipping point by 2057. It is a controversial result that is being hotly debated in scientific circles. Wired magazine provides the backstory to the paper and the principal researchers...

In conductive media like seawater, EM waves experience attenuation related to their frequency. The skin depth formula calculates the depth at which ##e^{-1}## attenuation is reached. The skin depth is inversely proportional to frequency. In practical terms, only extremely low frequencies (eg 80...

In Star Wars, they move FTL by accessing hyperspace which is a short-cut of sorts or like a wormhole that allows them to travel very fast without breaking causality as they are technically not in this dimension. FTL signals are also sent through this same dimension (called hyperwave...

Hello, would anyone be willing to provide help to the following problem? I can find the Fourier Transform of the complex envelope of s(t) and the I/Q can be found by taking the Real and imaginary parts of that complex envelope, but how can I approach the actual question of finding the carrier...

Could quantum entanglement be used to send faster-than-light communications across vast distances in space, in the distant future? For example, if humans establish permanent colonies on Mars, it would take some time to send communications between Earth and Mars. Could a future technology...

Problem Statement: I am not quite sure how to approach this problem and would appreciate the help. I how the C/N is closely related to the SNR (Eb/N0), but the question does not give the bandwidth or data rate for me to use the formula above. From the constellation diagram, my guess is this is...

Hello everyone, I'm trying to find the Voltage Carrier Signal and Voltage Modulating Signal from the power spectrum of a AM signal 1) I change the scale dBW to W and I have this: From this I have that Pc (Power of the Carrier signal) is 50 W and I don't know how to continue with the...

I feel like the emerging idea of quantum communications; is that you can exchange data via the synchronous states of entangled particles, across any distance, in real-time. But, there's also this dilation in the physical world, at the speed of light, according to relativity. So- how would the...

Summary:: Looking for a title and an idea to do a research project on the topic of satellite communications Hello fellow FP, I am in desperate need for an idea to do a project, seminar, call it what you like, on the topic of satellite communications for a course. We covered the basics of...

Hi,The data sheet of an antenna system can be found at http://www.tcs.la/Portals/0/TCSXY.pdf. This description is taken from it: Our XY pedestal is ideal for tracking satellites in Low-Earth Orbits (LEOS) because it completely eliminates the problem of the overhead keyhole (lost data effect...

Homework Statement a) If this mixer is connected to a matching 50Ω resistor, what is the conversion gain? b) IIP3 (Third Order Intercept Point) is 15 dBm, what would be A1dB? c) What is P1dB?Homework Equations https://www.ece.ucsb.edu/Faculty/rodwell/Classes/ece218b/notes/Mixer1.pdf#page=9 b)...

Homework Statement A wireless communications system can achieve a theoretical maximum data rate of 200 Mbps using 16-QAM modulation in a 10 MHz channel and using a single spatial stream. What data rate could theoretically be achieved if the same system used 256-QAM and 8 spatial streams in a 20...

Hello, I'm looking for some insightfull answers for the following topic: I have a (slotted) waveguide where multiple (50) antennas (for sending and receiving) are located in a slot that runs along the waveguide (200 meters long). On both ends of the waveguide are probes located for the wireless...

Lets suppose for SF story purposes, that the article is right that claims direct "counterfactual" communication through entanglement became possible, without classical communication channel. How should i portray that option? If information sent by detecting when, in which phase coherence is...

Homework Statement [/B] As part of my coursework in a sensor systems module at university I was given the question: State the most important reason why the photovoltaic (as opposed to photoconductive) mode would be the most suitable choice for a long distance fibre optic transmission system...

Could please someone explain me, if entanglement can't be used to direct communication (that would be an FTL dream come through) how untappable quantum communication supposed to work? If regular data transmit still needed to get any useful information out of the entangled particles, why it can't...

When, in wireless communications, does the inverse fourth power-law become relevant? My understanding is that is that what cause the average signal power to degrade to the forth power is cancellation from self reflections. So by my way of thinking, an LOS point to point system, like a...

Given that the time is relatively slower for a moving object that a stationary object, does the relative difference have an effect on satellite communications? For instance, if a geostationary satellite, which is traveling very fast to appear stationary on Earth (and therefore experiencing a...

Some years ago there was a news announcement about a quantum commlink between Beijing and Shanghai, more recently a few weeks ago there was the announcement of the first ever quantum communication satellite. I've done some looking but I haven't found any analysis about whether or not this is...

So, I've been wondering: how would time dilation affect communications? For the sake of visualisation, imagine the Flash is running at 99% the speed of light in a circle around a fixed position. There's a building in this position, and inside this building are his friends. Due to time dilation...

I think we all know what an Alcubierre drive is, well this is similar in principle. Is it possible to conduct faster than light communication through the acceleration of a bubble of space time? is it even possible to do this without a ship, and just send it out as a warp bubble from a point like...

How is quantum entanglement used in superluminal communications? I'm not sure whether I have the right idea of quantum entanglement (and if I do not, please correct me), but I wonder how quantum entanglement is used if the particles in entanglement are autonomous (that is to say, they can't be...

As I want to do higher studies in physics ( and unable to get a good Bsc (hons.) physics program) which Engineering should I choose Mechanical or Electronics and communications? From what I hear ECE guys end up doing software jobs after their graduation and Mech has better chance of doing...

Hello all, I have noticed that most of the posts here are not related to Digital Communications, a branch of Electrical Engineering. I search the Internet for Forums to discuss different topics on Digital Communications and I found EDAboard forums, with one forum to Digital Communications...

Hi all, I'm an student of Physics so apologies if I'm just some silly questions here. The higher frequency bands typically give access to wider bandwidths (e.g wifi). Considering that higher frequencies bands (> 30 Ghz) are more susceptible to signal degradation due to ‘rain fade’...

Why are raidowaves used for Wifi and Bluetooth but microwaves for satellite communication among other things. I was under the assumption that radiowaves are used for communication only. What are the factors which play into this decision. Also, is there a link between frequency of a wave and the...

Hey all. I will get straight to the point. I am about to get into graduate school and I have the option to choose between Controls & Robotics OR Communication & Signal Processing. I am kind of not sure what to pursue, the reason is because I feel if I choose one I will unfortunately lose the...

Hi guys, I'm currently studying Beng Electronic communications engineering. I'd like to know more about the careers of electronic communications engineers. What typical job would I expect to get? The problem is that I really enjoy electronics but have no idea what I'll be doing at a...

I know its risky to rely on wikipedia, but on the page on quantum entanglement, it claims that possibly instantly, as soon as one of a pair of entangled particles is measured (say A), then the opposite one (say B) takes on the opposite value. Now to know this, I assume B must somehow know the...

I just saw an article regarding NASA's Lunar Probe that will use lasers to communicate high resolution images and data from the Earth to the probe for faster comms. My question is...in Outer Space with no atmospheric influence, at what distance would laser communications like this remain...

What is meant by achieving "full diversity gain over Rayleigh fading channel"?

Here's a quick question...though it may stick on your mind for a while and become a long question. Are all light waves going to be stable for sending communications or is...this is semi rhetorical...the freqeuency of the light going to make the communication of data subject to interstellar...

Hey. I offer this idea in hopes that somebody with more knowhow can contribute. Basically the idea is this. Scan IR/Microwave/Radio wavelengths for recurring bits of information that can be sorted into a working language. If the language seems that it reveals information in some sort of...

At my college we can choose to branch off and focus on computers or more traditional EE classes. I really like E&M physics, but hated my signals and systems course. I'd like to take electromagnetics, but that means I would have to take communcations as well (which I hear has a lot of signals...

What would happen if an uplink and downlink had equal frequency. I know 'swamping' would occur, but what IS swamping ? Would stationary waves be set up ?

I'm thinking of doing graduate school in the near future and was wondering whether I should go for power or communications for electrical engineering. I am interested in both fields so the work load won't really be a problem. What I am interested in is the pros and cons of doing either field...

Hey all, I started reading up on string theory the other day, and a colleague told me that string theory is already being applied in communications. He said that it is being used to account for the effect of gravitation on electromagnetic waves. This seems a little too hard to believe...

Just a little background: I'm a junior in mechanical engineering and only recently have I considered getting a minor not related to my field. For a career, I plan on going into something involving space exploration (a little vague yes). Now about the communications minor: I, myself, am not...

Homework Statement Communications satellites are placed in a circular orbit where they stay directly over a fixed point on the equator as the Earth rotates. These are called geosynchronous orbits. The altitude of a geosynchronous orbit is 3.58*10^7 m. What is the apparent weight of a 2000...

Hi All, Please find the question in the attachment. I would like to know if the intergration I have done is correct. If the intergration is correct I am not sure how to approach the rest of the question. If someone can point me in the right direction to solves this I would appricate...

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) +...

Homework Statement Consider a speech signal with a maximum frequency of 6kHz. It is sampled at 10kHz and stored. Suggest a scheme to reconstruct the toll-quality speech signal as close to the original signal as possible. Homework Equations The Attempt at a Solution

Hey there.. Got couple of questions that i hope u guys can help clarify my answer.. 1)Is it possible to design system with infinite signal to noise ratio SNR at the output when the noise is introduced by the channel? answer:No, because as long as there is noise at the channel. formula SNR...

In his 1996 paper on http://arxiv.org/abs/quant-ph/9609002v2" , Carlo Rovelli proposed that “a complete description of the world is exhausted by the relevant information that systems have about each other.” I’m interested in exploring here what such a description of the world looks like. I’m...

How to respond to "too long" internet communications when you don't have time? Hey everyone, To make a long story short; what do you do when you feel really lacking the energy or time to respond to long e-mails or Facebook wall posts/comments on statuses..etc? A few days ago I posted a...

Hi, this may be the stupid question for you but its important for me to understand difference between these. I am making an application which requires hex communication between master and slave but the problem is with me that i keep on doing string coomunication eventhough my instructor...

Hello. I was wondering about something the last few weeks and that is if the solar wind can affect communication systems between satellites. I am not referring to the physical damage that the solar wind might produce to the satellite, but the interference it might have on the radio signal that...

I am getting a bit older, and I have a Aluminum Communications Tower, and used to angle it up by myself from the back of the house to the side. Now I would like to lift the tower to its vertical position on the side of the house using the existing aluminum angled bracket plasma welded to a...

Homework Statement Does anyone know why number 1 VHF communications system powered from 28Vdc Battery Bus or 28Vdc Essential Bus and not from another source such as 28Vdc Main Bus or similar power source. Homework Equations The Attempt at a Solution I was struggling to find reasons as to why...

Hi. Who among you know a site where I can find a wiring diagram or schematic diagram of PAM (Pulse Amplitude Modulation)? I badly needed a diagram of it for my prototype in Digital Communications. I've been searching for it in Google but it only gave me different diagrams and I can't tell...