Signal Definition and 990 Threads

Why not work with the complete signal, instead of breaking it into in-phase and quadrature components?

What type of technique would allow you to visualize the nerve electrical signal of the brain? Is it possible to do that with MRI?

We know that periodic function can be written in terms of complex Fourier coefficients: $$f(t)=Fn0+\sum_{n=-\infty,n\neq 0}^{n=\infty}F_ne^{jnw_0t}$$, where $$Fn=\frac{1}{T}\int_{\tau}^{\tau+T}f(t)e^{-jnw_0t}dt$$ and $$Fn0$$ is DC component. Power spectrum of signal is defined as...

Hey! How can I delay a sinusodial signal (voltage) 90 or 180 degrees? I have been thinking of a capacitor or an inductor in parallel with the voltage source but these components do not impact the phaseshift of the voltage but the current. Can anyone help me please? EDIT: I know that there are...

Homework Statement Given the following signal, ##v(t)=2\cos (2\pi f_{0}t)+4\cos (4\pi f_{0}t)+6\cos (6\pi f_{0}t)+8\cos (8\pi f_{0}t)## 1. Calculate the signal's average power in the time domain. 2. Calculate the signal's average power in the frequency domain. Homework Equations Didn't make...

Given the following signal, find the Fourier representation, ##V(jf)= \mathfrak{F}\left \{ v(t) \right \}##: ## v(t)=\left\{\begin{matrix} A, & 0\leqslant t\leqslant \frac{T}{3}\\ 2A, & \frac{T}{3}\leqslant t\leqslant T\\ 0, & Else \end{matrix}\right. ## Then sketch ##V(jf)##. Homework...

I am a little confused of the last step. We can set an upper boundary for any arbitrary large number M, so it seems ok. do you agree on the last statement?

I'll be doing a project that will need to acquire and process signals coming from one or two antennas. What is, in your opinion, the best software to do this? I've used LabView before and it worked alright but it was a very simple project, this one is much more complex. Is LabView a good option...

Hi, I am new in this forum and still can find my way around easily. Please forgive me if I have posted this in a wrong section. I need help from seniors in the field of wireless transmission. I have done a bit of research but not enough to justify any conclusion. I have a project to setup a LRS...

Multiple_Authors submitted a new PF Insights post Can I Send a Signal Faster than Light by Pushing a Rigid Rod? Continue reading the Original PF Insights Post.

I'm currently writing a book. In the book the main characters need to find the source of a signal but they can only use two primitive, non-directional receivers. I think it is possible to calculate the location providing they have access to a very accurate timebase which will tell them the time...

Hello I would like to measure a LVDS signal, on the board that is sending this signal. There are two signal pins on this board for this signal, signal-p and signal-n. How can I measure this signal? Can I use single ended probes and an oscilliscope? I tried to do that but I can't find a signal...

[Mentor's Note: Thread Moved from EE Forum] This link has the picture, for some reason it wasnt showing in this post. http://i.imgur.com/TYlb32t.jpg Here is my problem, I am supposed to use this circuit and solve for Av and Rin. My problem is that I have solved for Av but I can't solve for Rin...

What information can one obtain from the plots of the background vs signal efficiency? \epsilon_{bkg}(\epsilon_{sig})? In particular I attach some plots I made by hand and I want to understand how to obtain what each tells us.

Hello Forum, If we connect one of the terminals of an AC voltage source to ground, the earthed terminal will maintain the same electric potential as planet earth. Earth can be assumed to be a huge spherical conductor whose electric potential does not change (much) when connected to a...

Hello I computed, with python scipy.rfft, the Fourier transform of signal coming from an accelerometer. I don't understood what this is the meaning of having a powerful signal near to 0 Hz ?

Hello all, The root problem is that I can't put all my analogue inputs onto one input card (each card has 4 inputs) on the project I'm working on. We have four sensors, they should all output 4-20mA. Two are source type outputs, supply voltage goes in, sensor current comes out, current is...

Hi all! I have this problem: I have some data that come from a negative binomial distribution with unknown parameters and some additive noise with gaussian distribution of known parameters. What is the best way to remove the noise from the distribution of the data? I tried bot a very basic mean...

Warning...this requires scripting and iteration, and is not theoretical -- it is a real problem I haven't been able to solve, but I'm sure someone here can... :-) Data: each .csv file is a test recorded at a time interval of 7.5Hz and each file has 3 columns. The first column is time in...

Hi, suppose I have N number of events. Each event is assigned a probability of whether it is a signal event or a background event. Each probability differs from one event with another. Is it true Bayesian-wise, that, the number of signal events out of the N events is P(signal | event 1)...

Homework Statement I've been asked to sketch and mathematically represent the pdf of 2 signals: (a) rep2T{5 rect(t/T) - rect((t-T)/T)} (b) rep2T{2 rect(t/T) + 4Arect(2t/T)} A(t) is the lambda function A(t) = 1- t for 0 <= t <= 1 1+t for -1 <= t <= 0 Any help would be much...

Hello, I have a three phase brushless motor and was trying to measure its torque and speed using a torque sensor. The motor will first go to its maximum speed which is about 6000RPM, then I applied a brake to decrease its velocity. Here is what I get as a result of data acquisition : The...

Dear PF Forum, After so many questions about Twins Paradox and Universe Frame of Reference, I'd like to know about Lorentz and Doppler. First. Here V is ##\sqrt{0.75}## ≈ 86.60%. If we put V in Lorentz Transformation formula as speed, we'll have Gamma = 2. Okay here's the question. Two probes A...

what is difference discrete and digital signal

Hey everyone! Can anyone explain, why quadrature sampling works the way it does? i.e. taking 2 samples for the I and 2 samples for the Q. I mean I can understand if one tries to sample one mono frequency signal, say 40 Hz sine wave, on 0, 90, 180, 270 degrees, that is a sampling frequency of...

I am a video and sound engineer. There is clearly AM radio coming from my wall heater. An earlier thread on this topic discussed the possibilities but ultimately left the subject with an assumed crazy old lady's false perception. I assure you this is happening. There is a 50,000W AM station...

A person on Earth signals with a laser beam at 6 minute intervals. Another person on a rocket moving away from Earth at 0.600c detects the signals. At what time intervals does the person on the rocket receive the signals from the Earth. The formula we use is: Δt=Δto/sqrt((1-u2/c2)) u = 0.600c...

According to Maxwell's equations, $$c=\frac 1 {\sqrt{μ_0 μ_r ε_0 ε_r}}$$ in a medium with an electric permittivity of ##ε_r## and magnetic permeability of ##μ_r##. This means that in any medium which has values for these properties which are greater than that of a vacuum, the speed of light...

Suppose you are given a phase spectrum or (/and) equation of the (main) signal only and you are said that the given (main) signal is formed of 3 other signals. Is it possible to compute phases of these three signals from the equation or (/ and) phase spectrum of the (main) signal? Also,what...

I am studying Fourier Transform and it's inverse. We get phase and magnitude of a signal from it's Fourier transform and reconstruct it back from both together(magnitude of signal +phase of signal) My question is that is it possible to reconstruct given signal back using it's phase only or...

We know that Fourier Transform F(W) of function f(t) is summation from -infinity to +infinity product of f(t) and exp^{-j w t}Here, what does the exponential term mean?

This my homework: Input signal to system is: where H(exp(jw)) is transfer function of ideal low pass filter with cutoff frequency wg=3*pi/4 and zero phase characteristic. Sampling in A/D converter is done with period T=(1/125) seconds. a) Calculate output signal ya(t) b) Calculate...

Hi all and thanks for reading, I'm working on a concept and am trying to establish if there is a way to sniff a signal between an RFID tag and it's reader. What I mean by this is - is there a way an ON (1) can be generated when the tag and the reader communicate? I don t need power from the...

hi! when I send a square wave to a digital oscilloscope it detects the signal + dc signal. I wanted to know why. I was thinking about internal resistance of coaxial cable i was using. signal got out of an oscilloscope/wave generator and in channel A of the same oscilloscope/wg. It was +-1...

Basically I want to test my analog circuit using a forcing function that has a form of a delta function. The function generator I use outputs sine wave, triangular wave and square wave (+ve and -ve output in one period). Are there any ways to produce a square wave that has an output for like 5%...

I have an Antenna that receives signal coming from a wide band of distances, 10-2000 meters from a 10mW transmitter. I am working with 868 MHz band. What is the cheapest method ( or cheapest circuit ) to amplify this signal with an Automatic Gain Control LNA so that the received signal stays...

Let A= (sin(x) * sin(100x)) + sin(100x).; modulation index is 1; Let B= (sin(x) + sin (100x)); Both of these waves have same frequency and both are amplitude modulated. When passed through an envelope detector, both will give message signal. And B have an advantage of not having any sideband...

Hello Guyz I've got a little Question For Seniors I hope You answer it Briefly , I know that whenever i plug in my USB Drive in my Loudspeaker or plug Speaker itself in my PC and play anything like a song an Electrical audio Signal is Produced which is transformed by Speaker into a audible...

See attached file. I want to generate a waveform that looks like this using a function generator, where it repeats every f=1/T and the duty cycle is (t_d/t)x100.

Hi, I am new to world of electronics and to high frequency Domain. But I am working on a design where I have a coax of 30cm length. I have used an external oscillator to generate 7GHz fast falling pulse. I am using a Controller to control the oscillator. Now I have a pulse of about 350ns...

Hello everybody, nowadays I am working on shaping amlifiers and need guidiance about how to design one and do its simulations before pcb design and manufacturing. When googling about shaping amplifiers i found documents mostly about filters (active and passive), which i know works for rejecting...

I have a CW laser system, the optical detector receives a pulse width modulated signal and converts it to an analog signal. Both the source and detector have 32 channels and I would like to know what the analog signal power is, I thought maybe I could use the RMS voltage received on the...

Homework Statement Use Matlab to construct a signal of length 2^13 = 8192 that contains only three frequencies: x=0.5*sin(2*pi*200*t)+0.2*sin(2*pi*455*t)-0.3*sin(2*pi*672*t) Compute and plot the absolute value of the DFT. What does the question mean by signal length and why is it expressed...

I'm doing a project that has been done many times before, bouncing a signal off the moon, but I'm trying to do it with low power. I'm told the expected S/N ratio is -30dB. The problem I'm trying to figure out is whether or not it is theoretically possible to pull out the signal out from the...

Hi Folks, I have an article which explains the modulation of 2 signals given by X_1(f) e^{-j 2 \pi f t_i} and X_2(f) e^{-j 2 \pi f t_i} The only difference between the 2 signals is a time delay, however i don't see a phase difference in either expression It states the convolution of these...

Hello all, I have a DJI Phantom 2 Vision+ and I just recently had it painted. It is painted like a car would be painted. Ever since the new paint job, my drone is not flying right. It is displaying symptoms of Radio Frequency (RF) interference. The main issue is that it is now flying...

Homework Statement Assume that the power radiated by the television transmitter uniformly fills the upper hemisphere. A UHF television with a single-turn circular loop antenna of radius 8 cm requires a maximum induced voltage above 24 mV for operation. The speed of light is 2.99792 × 108 m/s...

I'm just coding a program where I've to calculate the individual frequencies inside an audio file *.wav file. The modulation is pcm and the information I've is a lots of points, like this: http://www.renesas.com/media/support/faqs/faq_results/Q1000000-Q9999999/samp_1.gif To be exact, I've...

Homework Statement I'm posting this question here at this point. I am having difficulty understanding autocorrelation in terms of solving the problem below. I don't seem to understand the math behind this. A white noise process W(t) with unity (N_0/2 = 1) power spectral density is input to a...

Hello everybody :) This is my first post! I have a mystery about radio communication that I was wondering about for a long time: If I have understood correctly, most computers have a single WiFi antenna in the shape of a rod, which is placed in a particular orientation. My question is this...