Signal Definition and 989 Threads

Disclaimer - I am not an expert by any means so this might be as much about confirming my understanding as an inquiry from the general public... as such, it might be fairly conversational as I attempt to clearly communicate my thoughts and understanding. Please excuse this. If gravity is the...

Here is my circuit for detecting zero crossing with Arduino (same circuit as this thread, but with the correction for the interrupt pin): Once again, I am using analogRead(A0) as an oscilloscope. The interrupts are detected fine, and my Interrupt Service Routine (ISR) is also being called...

https://www.scientificamerican.com/article/alien-hunters-discover-mysterious-signal-from-proxima-centauri/?fbclid=IwAR0HOFRU-cvFaU66Wbqql-hoo91hA1WnCl9Azwqa84ly-zS6cjBiDFzlK8o Excerpt: Most curiously, it occupies a very narrow band of the radio spectrum: 982 megahertz, specifically, which is a...

I am taking a class in signal processing. We have a final project in which we seek out "real-world" signal data and process and analyze it, and write a report on what we figured out. I thought it would be interesting to put my own interests into it and try to analyze a pulsar signal. My idea is...

Consider the following thought experiment... You are an engineer with a very peculiar assignment. With a mind to reduce the investment of excessive human labor and material waste, you have been asked to build an apparatus similar to an old-fashioned voicepipe. You are asked to ensure that the...

Hello, Looking for advice/thoughts on a PWM signal going across multiple PCBs. The signal would be relatively slow (1kHz) but I've really only ever dealt with PWM on a single board or cable. The premise of this effort would be to have a PWM control signal and be able to daisy chain multiple...

Summary:: An image was taken with a ##60## second exposure time of a 6th magnitude star and the signal to noise ratio was detected to be ##S/N = 20##. a. What should the exposure time be if you wanted a ##S/N = 100##? b. Now calculate the ##S/N## if it were a 2nd magnitude star for a ##10##...

I read about the non-communication theorem and I understand why when changing one practical will not change the other . But suppose that there is two observers that doing the double slit experiment, but using it with two entanglement practicals. observer one should send signal of yes or...

Hello everyone, My question for this thread concerns the application of (mainly) mathematical analysis to fields such as signal processing and machine learning. More specifically, I was wondering if you happen to know of some interesting application of things like measure theory or functional...

Suppose the Martian sends a signal to Earth, the final flash of which is emitted exactly four minutes later than the initial flash. In that case, with a favorable position of the planets, the final flash on Earth will also be observed neatly 4 minutes later (and 4 light minutes further than at...

I would like to estimate the magnitude of a radio signal received from a transmitter by first principles: Transmitter antenna length ##L=1## m Transmitter antenna area ##A=1\hbox{ cm}^2## Number of electrons per unit volume in antenna ##n_e=10^{28}## Radiation resistance of antenna ##R_R=10\...

Hi all! I have a complex waveform, something like what I have attached, and I need to extract the RMS and Peak Voltage from this. However, this signal can and will change after a number of cycles on a certain setting. So, this means the period and duration of pulse can change and so can the...

I'm thinking that I am going to need something like a low pass filter around 100 Hz so that low noise disturbances from a nearby PSU and such won't disturb my sampling. However, the unit will have to operate around 50 Hz sometimes. Is it possible to use a Fast Fourier Transform to filter out...

I got a gesture sensor module that produces a signal per event. The each signal is a set of regularly sampled readings from four photodiodes. The number of samples per event can be very different, from around 20 up to over 100, and each sample value is essentially the measured brightness...

Hello, When I tell this story, I usually get brushed aside for being senile but people who know about physics might be more useful. About a week ago I was woken up with an alarm from my clock-radio. That was odd as I had never used the alarm function. Unable to find the cause, I assumed the...

I've read a couple of other topics on the Physics Forums about the lumped circuit abstraction requiring that signal timescales (i.e. the period of the highest frequency signal component) be much longer than the propagation delay of the signals though the circuit and that the wavelength should be...

Let's assume the following sine signal sent by a low frequency (100 kHz) transmitter. I think with the information that the sending power is 1 watt and the starting phase is 0 the signal is fully described. Are the following assumptions correct?: 1. The frequency of all photons leaving the...

Having some trouble with this question I believe phenomenon behind this one is that the student is passing between nodes (minimum displacement) to antinodes (maximum displacement) which explains why the signal weakens and strengthens continuously. Hence the ans to this is option C? For the...

I need to perform a phase shift for a measured time domain signal. The signal consists of around 1000 points. I wrote an algorithm for this in Python a while ago and it seems to work as intended, but now I noticed that the algorithm is actually unexpectedly slow. Is it so that phase shifting is...

The other day my friend asked me a really interesting question regarding the scene from interstellar where they go down to Miller's planet, where every hour on this planet is 7 years of Earth time. He asked me if they were to send a signal to the spaceship where Romilly was, what would happen...

I had a talk with a friend of mine , just wanted to make sure I'm not wrong. I actually have one older CRT set with an open back in another room so I went to check my "question" out a bit before asking. 1) Is it right that the video signal (after some input demodulation etc boards) directly...

%My code: %Type of signal: square T = 40; %Period of the signal [s] F=1/T; % fr D = 23; % length of signal(duration) dt=(D/T)*100; N = 50; %Number of coefficientsw0 = 2*pi/T; %signal pulset1= 0:0.002:T; % original signal sampling x1 = square((2*pi*F)*(t1),dt);%initial square signal t2=...

Hi all.I would like to know about "binning window". This paper I'm reading says like this. Why do "convolving the data with the ##b(t)## before the sampling" and "binning into time bins with a width ##δt##" have the same meaning? I know I'm addicted to post to PF 😅 But this forum is so...

Hello all, I have a monochromatic laser peaking at 808 nm and some non-scattering sample. I want to measure the absorption with a spectrometer. I can use the Beer-Lambert law to do this, but since it is a monochromatic laser I have some doubts. I could do a weighted-average, taking into...

Is wavefunction always analytic signal? Is imagnigray part of wavefunction hilbert transform of real part of wavefunction?

I started by working out the time constant of the Capacitor = RC = 300 * 1.5*10^-9 = 0.45 *10^-6 and the time period (t) of the square wave signal produced by the signal generator : 1/(1*10^6 )= 10^-6 Then I drawed the graph as follows...

Formula I have shows is probably for resulting harmonic? Does syntesizing mean writing the main formula? I havo no clue about effective value of signal and representation is probably done in excel or other graphing app.

Suppose I have two audiofiles in 16 bit PCM, both recorded on a level that, except for the noise and distortion, is maximally recorded, or that the maximum recording level results in the maximum PCM level. So, the signal is recorded on the maximum level such that there is no clipping. If we...

Hello, I have done an experiment with cutting out a pulse from continuous laser using Pockels cell. The setup is cw laser -> Pockels cell with crossed polariazers -> photodiode. The photodiode is connected in reverse bias, a capacitor is connected parallel to photodiode. If I put a half wave...

I am trying to reconstruct a signal, and looked at this example: https://www.mathworks.com/help/matlab/ref/fft.html Towards the middle of the page, there are two frequencies: 50 Hz and 120 Hz. How can I approximate reconstruct the initial signal given these two numbers? What I've been doing so...

Hi PF! Attached are two plots: signal.pdf is a solution from the Duffing ODE, and plots vertical displacement over time, both the raw signal (blue) and the reconstructed signal from an FFT (red). I've also shown a zoomed in view so you can see how oscillatory the signal is. pow.pdf plots the...

I'm looking for a class of IC's which takes a high voltage signal (200-300V) as input and then distribute it to one of the output ports I choose to use through the other input ports. It's awkward but I can't find anything out because I don't know which keywords I need to use.

I was assigned a project where I need to have a heat sensor send a signal to my phone and cause it to sound an alarm. If my phone is an android what is a good app programming tool for this project, I’ve never done app programming. Would I be able to send a signal from the sensor to the phone...

Basically, I'm wondering how you can essentially determine the bearing of a signal source, if you know its signal strength. assuming you're in a vacuum, and you have a beacon transmitting a signal, and you know its signal strength. How could you find out the bearing (direction) it's at, if you...

https://www.upi.com/Science_News/2019/07/30/Mathematical-model-identifies-acoustic-signal-preceding-seismic-shake/4431564489814/

Namaste I seek a clarification on the periodicity condition of discrete-time (DT) signals. As stated in Oppenheim’s Signals & Systems, for a DT signal, for example the complex exponential, to be periodic, i.e. ej*w(n+N) = ej*w*n, w/2*pi = m/N, where m/N must be a rational number. Above is...

Hi, I'm trying to model the transmission loss and SNR of an acoustic signal underwater. I'm using this expression to modelize the transmitted signal: y = sqrt(P)*exp(1i*2*fr*pi*t)' where P is the transmission power in watts, fr is the transmission frequency and t is the acquisition time. The...

Hi everyone, I'm pretty new to electromagnetism and have no experiences in this topic. I have a signal generator (Digital Dual Channel Funktion Signal Generator) and want to generate two signals (530 and 550 Khz signal) and want to transmit these generated signals to the points on a table...

Hello people, I hope someone can help me with this exercise. This exercise is taken from the book "Applied Digital Signal Processing: Theory and Practice" by manolakis and Ingle. I don't understand what is being asked. The only thing I understand is that I have to use MATLAB necessarily. Someone...

I do not know how to declare time t and unit steps. The image of problems to get a better understanding as well.

I'm working on a wifi device testing box and made the first prototype of the Faraday cage. I need holes because of cooling. For this reason, the box has 3mm diameter holes on the top. The box made from steel, and have 2mm wall thickness. The wavelength around 12,5 cm for 2,4 GHz and 6 cm for...

Hi, I'm an electrical engineer for a few years now, but it's been a while since I had to deal with this kind of stuff, I turned out to become mostly a programmer in the end, but i was thinking: is Gibbs phenomenon, which was demonstrated to me during my studies while working on Fourier series...

I removed a condenser microphone From a sound meter. I plug it in a breadboard. But the Condenser microphone won't produce a voltage or signal. I tried yelling into the microphone. I tried Connecting a battery to circuit. Nothing I tried worked. Anyway to get microphone to pick up signal?

Ok, so in the interest of full disclosure at the outset, I'm a 69 y.o. retired epidemiologist who has an interest in HRV signal analysis specifically, and physics as a whole--always have. Am not an EE, physicist or mathematician so be kind, if you will. This is my first post. In signal...

Homework Statement y(t) = x(1-5t) Homework Equations noneThe Attempt at a Solution well I've never looked at the stability of a signal which has a time scale and shift. My guess is that it is stable as anything I can provide as input will output a bounded signal. Ex: if x(t) is u(t) then...

Homework Statement Prove the discreet signal is periodic: Homework Equations for periodic funtions: x[n] = x[n + N] The Attempt at a Solution I made an equality (im going to leave the sigma out for simplicity): 2^(-abs(n-2m)) = 2^(-abs(n+N-2m)) I don't know what I need to do from...

I have a couple quick questions on keyboards with a USB 3.0 cable. When we first turn on our computers, is it the 5V pin that turns on the keyboard? When we press a key such as 'esc' or 'enter', through what pin(s) do these signals get sent to the computer? Thanks!

Hello. I'm studying Fourier analysis. If we look at attached graph where Gaussian functions are transformed by Fourier analysis, we can find Gaussian functions in frequency domain have maximum value at 0 hertz. So I confused what is the Nyquist frequency at Gaussian signal. I need to know...

Hi everyone While learning about quantum mechanics, I became curious about the real-life experimental data. Wikipedia says that entanglement experiments require coincidence counters, because the majority of the signal received by detectors is noise. It further says, that coincidence counters...

Hi all. So is anyone having any luck with sw. power PCB mount supply modules for mixed signal? I have been experimenting with little DC-DC +5, +-15 and the TDK-Lambda AC/+5/+-15 power module. I have a mixed signal design that has a small size and low weight factor in my design. I have about...