Pulse Definition and 348 Threads

Hey, The question sounds like this: I have 100 fs 400 nm pulse passing through the CaF2 crystal. After passing, it gets twice wider (200 ps). What is the length of the crystal? Can anyone share the equation which would help me to calculate this? Thank you in advance!

Hello, I wanted to ask, if anyone knows of a realistic circuit, which could be capable of producing a PWM of 1 pico second on and 350 ps off. Thanks to everyone taking the time to answer in advance.

I heard about electromagnetic pulse, that it can cause damage to electronic devices if one intentionally shots out such a burst. But I wonder, wouldn't that person him/herself be affected by the pulse? I mean, the pulse would work like a lighting. So that person could even die by his/her own...

Lets say I have an LED that is being pulsed once every two seconds. The LED uses 5 mA of current each time its fired and the pulse lasts for 40mS. I know the current into the LED because I measured the voltage drop across the dropping resistor of 420 ohms with a good O-Scope. So I know all...

I am currently working on a small personal project to design a few circuits. I am trying to built a circuit that can detect 100 uV pulses with a pulse width of about 10 uS. I'd like to boost the voltage to a value readable by an FPGA (let say ~2 volts). I'm currently thinking about the...

i'm new on creating my own circuit. And I'm trying to create a digital clock, using 74ls90+74ls47 I have problem on creating 1hz square pulse part. This is my teacher's Simulation I have searched on google that i can create 1hz pulse by using NAND gate, crystal, or Ne555, but i can't find any...

Homework Statement [/B] Over 40 years ago, the Apollo astronauts placed reflectors on the surface of the Moon. These are still used by a number of observatories on Earth to monitor the distance to the Moon by reflecting pulses of laser light from them and detecting the reflected signal...

Hi there, we have a NMR spectrometer equipped with a standard bore 54mm cryomagnet working at 14.1 T (600 MHz Larmor Frequency) produced by Oxford. I would implement a special probe capable of generating a RF pulse and reading a NMR answer from a sample that is not standard for such...

I have the following program that moves a wave on a string with fixed ends. The program solves the wave equation given a initial condition wave. The initial condition is a triangle wave splitting into two pulses. Here is the code written in Python: from numpy import * from matplotlib.pyplot...

Hi, I would like to create an electric or magnetic pulses in an open ended cone, sphere or a tube. The pulse would have to be generated in such a way so that it is not actually connected with the container in any way (ie. it can't be a device in the center of the container which generates the...

Just wanted to share this, mainly because I really liked the videos (found in the supplementary section at the end). Moderators, feel free to move it to a more appropriate place. Observation of laser pulse propagation in optical fibers with a SPAD camera Recording processes and events that...

Hello! Starting from a gaussian waveform propagating in a dispersive medium, is it possible to obtain an expression for the waveform at a generic time t, when the dispersion is not negligible? I know that a generic gaussian pulse (considered as an envelope of a carrier at frequency k_c) can be...

This came up in a discussion in another forum - the context was the gravity of a photon... for which we need quantum gravity. But imagining a pulse of monochromatic light, it was asserted that it's gravity could be well approximated by replacing one of the mass terms in Newton's Law by E/c^2. I...

Could someone please explain to me what is the definition of a pulse current discharge, and what do we mean by pulse current discharge test ?

Hello Physics Forums I’m doing some numerical studies on diffusion. I began with monte carlo simulations on gas diffusion, and more recently I’ve started to dabble in carrier diffusion inside semiconductors. It looks like diffusion in semiconductors is a lot more amenable to experimental study...

I was looking for a qualitative explanation on how radiation occurs classically and came across this diagram. Which is for an accelerating charge. Then I started thinking if this break can occur for the gravitational field. Does the same thing happen for the gravitational field lines for a...

Hi. I need some help in explaining in a simple way how to calculate the minimum allowable frequency at a certain voltage when selecting a pulse transformer. The one I'm looking at has an ET value of 45Vusec. I'm feeding it 22.5KHz at +/-6VAC square wave. It seems to work fine but I fear it is...

I've been thinking... Is there any way that there could be sort of a one-time use pulse laser that uses something like a mini atomic bomb to create a super high energy laser? I found stuff about a Nuclear pumped laser and "Project Excalibur", but I wanted to ask actual people who know a lot...

Dear All, Suppose we have a electromagnetic/x-ray pulse with fixed energy with finite line width. I want to know the schematic of a plot how it looks in time- and frequency-domain? I think I understand in time domain: there will a straight vertical line on plotting intensity vs time in x-axis...

Hi there! is anyone here working with a pulse generator? I have Agilent 8114A Pulse generator i want to vary the frequency automatically like 1.1Hz to 10.1Hz with 1-2 secs delay. This pulse generator have a HP-IB bus at the back that can connect in a PC. Base on the Manual it can program using...

What are some effective ways to convert a Pulse Width Modulation from a Microcontroller to a DC Voltage as a function of Pulse Width? 1. Use a low pass filter to remove the unwanted harmonics and leave only the 0th term of the Fourier Series. What produces a better DC Voltage an Active or a...

I am reading the book "Super-radiance Multiatomic Coherent Emission" by Benedict et al. and on pg. 32, they discuss the initial conditions for a particular case covered by Burnham and Chiao (1969). It mentions that the system was "excited to a state with angle ##\theta_0## by a short coherent...

Homework Statement Homework Equations T= 2pi*sqrt(L/g) The Attempt at a Solution T= 2pi*sqrt(0.325/9.8)=1.14 s That seems like a reasonable answer. [/B]

The magnetic moment of protons precesses at a frequency ω0=γB0 about the static magnetic field. In order to move the magnetisation vector into the transverse plane the RF pulse must be applied at a frequency ω0. However, as B1 (the field strength of the RF pulse) is << B1 how is this possible...

Hey guys, I really need your help. I got the following task: "Sketch the output spectrum of a mode-locked Ti-Sapphire laser (assuming eg. gaussian shape) and calculate the shortest possible pulse duration by Fourier transformation." So the spectrum is gauss shaped but I have no clue how to get...

The inspiralling oscillations of ~20ms period (reducing to ~5ms) appear much stronger than the ringdown of ~ 3ms period (noisy, at resolution limit). Merger happens at ~440ms in the figure of Abbott et al. (Phys Res Lett link.aps.org/doi/10.1103/PhysRevLett.116.061102). This would agree with...

Homework Statement An electronic device is designed to amplify signals in the frequency range 80 MHz to 111 MHz. what is the smallest duration pulse in this frequency range that can be amplified without distortion? Homework Equations T=1/f The Attempt at a Solution the smallest duration...

I'm trying to understand the effect on a metal alloy of UV light (diode or laser) pulsing at about 1MHz. I am assuming that the stirring of atoms will generate heat, possibly moving the alloy to its eutectic point (depending on the alloy) and in particular to atomic motion. Can anyone...

Hi Guys, I'm new to the forum. I'm an engineering student studying process and chemical engineering. I am currently a member of a group that has been tasked with designing a plant to produce infant formula. The goal is to manufacture a ready-to-feed infant formula product, so that the parent...

Hi Guys, I'm new on the forum so forgive me if this has been posted before. I'm kindly looking for some advise to build a pulse coil set up to spin a 13,00 gauss 1" diametrically magnetized magnet. I was hoping to use 120 volt rectified dc or the highest voltage that has readily available...

Hi all, I've been using a HV step up transformer (10kV-20W on secondary) lately and I'm wanting to look at the HV pulses on an oscilloscope. The coil is isolated from ground. I know connecting a probe directly to it is dangerous and would ruin my scope. I want to use a differential probe but...

Does an accelerating charge, such as one turning a corner emit an em wave or just a pulse? Classical logic dictates it should just be a pulse as there is no oscillation. But which is it?

Homework Statement What is the Fourier transform of the function graphed below? According to some textbooks the Fourier transform for this function must be: $$ab \left( \frac{sin(\omega b/2)}{\omega b /2} \right)^2$$ Homework EquationsThe Attempt at a Solution I believe this triangular...

Hi folks, I need to get a super capacitor which will be charged by a car battery and then connected to let out a massive pulse. (Yes a bigger pulse than my 450CCA battery can give). But first I need to work out how much capacitance will be needed. I'm not sure of the formula. Thanks

In images I always seen pulses as a part of a wave corresponding to an half of a piece of wave, but it is called still a pulse when we have a part with a complete wavelength? I mean this (in the photo) And what the difference between waves and pulses? What I think is that is still a pulse...

Homework Statement [/B] The textbook is talking about pulse spreading/dispersion in optical fibres. Book says: "The spreading of the pulse is due to two dispersion effects: (i) Chromatic dispersion occurs because the refractive index of the fibre is different for different frequencies...

I need to convert light energy: 138W/m2 to uJoules / mm2, at a 4usec pulse J = W * seconds J = 138 W/m2 * 4e-6 = 5.54e-4 J/m2 5.54e-4 J/m2 = 5.54e-4 uJ/mm2 answer: 5.54e-4 uJ/mm2Does this look correct?

Homework Statement A transverse pulse is propagating on a 2.0 m long string of mass 50 g. The pulse is described by the equation: y(x,t)=pi/(pi+(3x/2+pi(t))^2) , with x and y in meters, and t in seconds. Find the tension in the string. Homework Equations y=asin(wt+thetha)[/B]The Attempt at...

Any one know circuit inside DC boost step up pulse generator? I have this one buy from ebay 400Kv type,i want to know how this work by circuit inside.. I had googling and not found result.. Please help me..

hi dears i need your advice. i wand to produce high pulse dc current in below described circuit: - power source is lithium battery 3.6 v (limited output current, maybe 1A) - load is resistor 0.01 ohm - current by value of around 50 A during 0.001 second need to be passed from the load. -...

Hi, The following question is related to my individual design for an engineering subject. I am trying to calculate the fluid displacement in a packed vessel when air is pulsed through a pulse leg, which is connected to the bottom of the vessel. Using equations from literature, I have...

I am making a small solid state tesla coil. I have the secondary coil, toroid and primary coil but am not sure what to do for a control circuit. I was planning on using two 9 volt batteries for power. Would a DC to Pulse Width Modulator work? This is the one I was thinking of -...

Homework Statement a non uniform string of length L and mass M, has a variable linear density given by μ=kx where k is the distance measured from one side of the string and k is a costant. a) find that M=(kL2)/2 b) show that the time t required to a pulse generated from one side of the string...

Hi, I am referring to a pulse as one single 2π radian wave of preferably two frequencies at either end of the range. By two frequencies I mean that I would like to know if the detection of an audible continuous tone differs from their single oscillation frequency and/or intensity.

Homework Statement A pulse of length 28.7 cm is transmitted from a thin rope to a thicker rope. If the thin rope has a linear density μ1 = 0.316 g/m and the thick rope has a linear density μ2 = 1.85 g/m what is the length of the pulse in the thicker rope? Homework Equations...

Hello, my name is Alexander Radchik and I have always wanted to be an atomic play boy. Given the lack of easily obtainable fissile material I have had humble myself to the theoretical use bombs for things that make sense. Regarding my query, I have 2 questions. 1) could a reusable nuclear...

Hello I need help for a basic question (i am awful in physics) :confused: I have two capacitors in parallel when they are charged up (18.5 kV) they release the energy to a discharge device. The discharge device releases the energy in the form of electric pulses through two electrodes in a...

Hi, I have a question. So, I've built this simple RC circuit. Of course, the pulse width is then obtained from the oscilloscope. But, according to equation Vo(t) = E(e^(-t/RC)), the value t (pulse width) is larger. Considering the resistor, condenser, Voh, Vil, IC delay, and others, how should I...

Homework Statement I have been given this problem but I don't think I'm doing it right as I have just disregarded n0? Calculate the maximum length of material (nonlinear refractive index n2=2.5×10-19 cm2W-1) that can be traversed if the total accumulated phase difference between the beam...

How can an ultrashort pulse, such as in a time frame of femtosecond, be detected? Is it possible for a slow detector to pick up a signal in a time of femtosecond? How does an autocorrelation play a role here?