Signals Definition and 410 Threads

Is there any other way to send signals a significant distance other than with EM radiation or (doubtfully) gravity? By signal I mean the complex information that we are able to send via radio or other EM transmission. I don't think there is any other way other than EM radiation but I cannot...

Can the aggregate brain waves from a stadium crowd register on a state-of-the-art EEG at midfield?

How do you "read" the flirting traffic signals women send men? Have you noticed that when you're around someone you feel attracted to, you feel different on the inside than you do when you're around someone you aren't attracted to? Well, apparently we send off subtle body language signals when...

This suddenly came up in a MRI class. I kinda understand IQ modulation (both amplitude and phase are modulated). But how does IQ demodulating a signal help, specially MRI signal. In case you don't know a MRI signal, its just a exponentially decaying sine.

The other day, I was sitting down watching TV, then I turned the TV off, and the DTV, and I noticed a sort of ringing high frequency humming in my brain. But the strange part was that when I turned my head 90 degrees, it stopped or got really quiet. Turned my had back to normal position sound...

what are the preprocessing steps to be performed on a speech signal in order to extract its fundamental frequency accurately? which sampling frequencies and cut off frequencies are to selected to get a better result?

Can a generic, not necessarily harmonic, signal of time be represented as a complex signal with a real and imaginary part? Usually the complex rappresentation is used for time harmonic signals and linear systems. The "real" time signal is transformed into a complex signal. At the end of the...

Could someone explain to me the meaning of the following concepts: 1. Filtering out AC: is used to reduce the ripple of a DC power supply. 2. Filtering out DC: Only time-varying signal will pass through a capacitor. The circuit on either side of the capacitor can be at different DC...

As stated in title: I have full knowledge of the 2 signals. They have the same Power Spectral Density. However, only certain components of the 2 signals have the same phase. Is there any way of extracting these components, or at least their PSD functions? Is this doable at all? The phase I...

Ok I've got an output from a mp3 player which has two channels (L & R) however the device I'm connecting it to can only output mono sound, so what I did was merely connect the left and right channel wires together but what I'm wondering is AC signals are not so clear cut to me, I'm currently...

I know that y(t) = t x(t) is unstable, for bounded inputs yielding unbounded outputs, but would y(t) = x(t)/ t also be unstable? when t is going in the negative direction? please help. test Monday.

I was wondering what kind of things you would need to transmit to a satellite or something on Mars and get video and whatever other signals back from there. Like transmit controls there for a rover to take and possibly to bring it back. So for the journey there and back.

I want to transmit digital signals over an existing electrical network. Can someone give me an idea of how to go about it?

I know what complex numbers are, but what actually is a complex signal as opposed to a real signal? I know a little Fourier Transform and in that context it is described as the difference between a cos wave and sin wave signals. But when I read about it in mobile communications it is described...

Need help! Digital signals. Energy and power Homework Statement ∞ ∑ (3)^2n n=0 FInd the energy of the signal Find the power of the signal The Attempt at a Solution Energy: (3)2n = 32+34+36+...=9+81+...= ∞ N Power: lim (1/(2N+1)) * ∑...

O.k., I'm not sure how to phrase this, but I'm going to try. If I'm confusing in my question, just ask for a clarification. I want to know how detecting the source (or direction) of an interstellar signal works? Specifically, a theoretical signal sent from an alien civilization at us. For...

Hi guys..how do u generate two identical voltage signals using the simplest BJT circuit?appreciate any help...

Why is it that very low frequency signals cannot be transmitted by antennas? (Or why is it inefficient?) Thanks!

Dear All: Any idea for the following interesting question: As we know we can calculate inner product of two wave functions A and B as <A|B>. here both A and B are vector in hilbert space. here we may use fourier transform to get momentum representation of A and B, and get same...

how does one calculate a gain in signal e.g sine wave. do we take peak-to-peak (or peak) of the output divided by peak-to-peak(or peak) of the input?

When someone gets hurt or infected, its usually very painful when the doctor works on that exposed area. The only reason why you feel the pain is because the nerve ending shoot electrical signals to your brain. Would it be possible to devise an electromagenetic collar that goes around the arm or...

Hello there, My project is a Smith Chart calculator/simulator that takes the Zo and ZL of a transmission line and calculates various data like SWR, SWR(dB), return loss, coeff I, E, P, etc. It also constructs and plots on a graphical Smith Chart. I want to take this one step further and...

I ran a time-domain simulation in HSPICE & I am trying to analyze the frequency content of the transient current draw...(FYI- I have the power systems "impedance vs. frequency" curve, and my aim is to determine the noise voltage on my power rail given its impedance now) So I run FFT...

Would there be paradoxes arise if information could pass instantaneously? If there where no limit how fast things can move. I know that in SR when faster then light travel is allowed, the casual order differ for different observers. Are there paradoxes in the classical Galilean space-time...

Is it possible to separate a specific frequency signal from a wide range of signals from a decoder/demux. For an example if you had a frequency range from 1 hertz to 100 KHz, is it possible to separate a signal of let's say 60Hz from the other signals.

Hihi, I don't understand what is the meaning that BNC cable transfer high frequency signal? For example, I use BNC cable for the connection between my diode controller to the diode laser. I also use BNC cable to connect my photodiode to the oscilloscope. I'm not sure what is the...

I was wondering, If we had a system in which we limited the stray capacitance by shortening the cable (standard co-ax) to about 1 foot, and we put a REALLY fast signal down there, say of the order of fs. Would we see a sharp spike which was of the order of the RC time constant (capacitance...

Group, I am a novice on learning Signals and Systems on my own . Got hold of Schaum Series on Signals and Systems after reading its reviews. I got confused in the "response of a LTC(Continuous-time LTI system) to an arbitrary input" Can somebody give me an idea about this? Also...

[SIZE="5"]please help me in this problem: two discrete signals x[nT]={0 0 1 0 0 2 2 2 2} h[nT]=[-1 2 3 3 2 1] find there convolution if the impulse response doesn't start from zero ,use the table or the matrix

[SOLVED] Speed of signals in digital phone line? I know that the rate of information transfer in a phone line is 64 kbit/s. I originally thought that this rate of info transfer was the same as the speed of transmission but I now know that this is not true: the speed = distance / time for signal...

Hey guys, For school I have to study the zero-crossing demodulation method of reconstructing an FM signal. So far what I've been reading has been confusing me a bit and I have a few questions to ask: 1) How does a LP-filter act as a "time averager" for a train of impulses? 2) Does the...

hi all, i was wondering what is the most correct approach concerning this function, since sometimes i find that the function is discontinuous at t=0 and sometimes its not. why is that there are 2 interpretations for a single function? bit confusing... P.F.

Hi, I'm thinking about transmitting digital signals with FM. The effect I'm trying to achieve is FSK. Can I just feed the digital signal to the input of the FM transmitter? With FSK the carrier is frequency modulated with 2 frequencies, but since the digital signal has infinite bandwidth...

hi everyone, i had a class where my teacher was talking about this but i don't know where this comes from, if anyone knows could you please give hint on the type of material this is. Like what type of mathbook i should be looking for. the problem was: Demonstrate the following...

Hi all, i was looking for this book "Signals and Systems" Alan V. Oppenheim, i would like to now which is the lastest edition or the diference between them. i have found this: https://www.amazon.com/dp/0138147574/?tag=pfamazon01-20 and this ...

I'm sending in a sine wave with an A = 120mVpp, f = 200 Hz into a http://hyperphysics.phy-astr.gsu.edu/hbase/electronic/opampvar5.html" to invert the signals into the positive range. After some circuitry to work with the signal after I've applied the sine wave + offset, at the end I want to...

If I have a simple microcontrol, say 8 pin PICAXE. Could I use it to read the voltage going through a circuit directly? And can I output varying voltages?

For the question stated in the pictures attached to this message, for part d of the question, I just can't picture why the convolution of the two signals is 1. Can someone please explain how this would be the case as the triangular signal is sweeping through all the delta functions? Thanks.

Homework Statement If a(t) is periodic and is composition of two signals such that a(t) = b(t) + c(t), then are b(t) and c(t) necessarily periodic? 2. The attempt at a solution I think that b(t) and c(t) must be! Is this correct?

Okay: here's the question: It's a well-known thing that when you add two sinusoids of equal amplitude and different frequency then you end up with a signal with the mean of the frequencies and a beat envelope. This just comes from the trig identity: \cos(a) + \cos(b) = 2\cos(\frac{a+b}{2})...

I've been puzzling how it is that you can tune into a signal on a particular frequency. How can it be possible to get rid of all the other signals that are added together? I don't know how much of this makes any sense, but I have tried to specify the problem mathematically. Suppose R_1(t)...

Hi, I have a question about Fourier Series(FS) in my textbook which is persentted like this: The uniqueness of a FS means that if we can find the FS of a waveform, we are assured that there is no other waveform with that FS, except for waveforms differing from the waveform under...

My colleagues and I are building a phase adjuster for LFN (Low Frequency Noise) audio signals. Since we would like to be able to adjust a range of signals that encompasses a range of around 50-400 Hz, an op amp-driven, analog solution would not be economical, nor efficient. Since we need to be...

I am looking for a way to calculate the power spectrum of short signals of variable duration (between 200 and 500 ms). Standard methods seem wildly inaccurate. Are there any tricks for short segments? Thanks anyone for a response.

Homework Statement http://img166.imageshack.us/img166/1162/untitledte2.jpg Homework Equations Convolution y[n] = x[n] * h[n] The Attempt at a Solution I've never done convolutions going backwards.. right off the bat, I know I'll noly have 2 terms in the convolution sum...

Hi, I have this problem about signals that I have a little trouble to finish: I attached a small figure of the circuit. I cannot figure out the answer and I struggled for 2 days. It is a High pass filter, and the ODE of the circuit is: \frac{dx[t]}{dt}=\frac{y[t]}{RC}+...

Please bare with me here, you will quickly see that I know just enough on this subject to be dangerous. I'm trying to switch two audio signals on and off into one Aux audio input of my motorcycles stereo system. I have a Satellite Radio that I want to hear most of the time. I also have a GPS...

Quick question about a discrete unit impulse. If I were to draw delta[n+1], at ... etc n = -2 ... the point would be at location: 0 n = -1 ... the point would be at location: 1 n = 0 ... the point would be at location: 0 n = 1 ... the point would be at location: 0 n = 2...

Homework Statement For the top example: x(t) = u(t+1) - 2u(t-1) + u(t-3) For the bottom example: x(t) = (t+1)*u(t-1) - t*u(t) - u(t-2) The example asked for a sketch, so sorry if my drawings aren't to scale. Homework Equations Unit step: u(t-t_0)... * if t_0 is positive...

Homework Statement Suppose you are developing a high-fidelity soundsystem. If you wish to deliver low-freq signals to a woofer, what device would you place in series with it? A) Resistor B) Capacitor C) Inductor Homework Equations The Attempt at a Solution According to my book...