Pulse Definition and 348 Threads

If a source emits a light pulse then waited one second and sent another pulse does the distance between the two pulses remain constant ? If yes is that mean their relative speed is zero? But why when we use lorentz transformation their relative speeds gives us zero over zero but if they travel...

Considering that when you compress a gas, the gas will heat, then when a neutron star collapses to a black hole, I would expect the neutron matter to be heated to extreme values as the collapse proceeds. I would have thought this would lead to a last gasp pulse of em radiation before gravity...

what will happen if two one femtosecond(1 fs) laser pulse interferes?

I'm reading book from here. Suppose two rockets are accelerating with the same acceleration ##a## and are separated by some distance ##z##. At time ##t_0## the trailing rocket emits a light pulse. The book tells that pulse reaches leading box after time ##z/c## as seen in background frame. But...

Which type of dosimeter is best for pulse short (duration let say 10 ns) dose measurement purpose?

I know a laser is generally treated as a coherent state (i.e. a plane wave). However, if a laser turns on and back off quickly, can the resulting light be treated as a gaussian multiplied by the plane wave that would have been emitted if the laser were continually active?

[Mentor Note -- This thread is a continuation of a previous thread, with the emphasis in this new thread on the programming implementation. Previous thread is here: https://www.physicsforums.com/threads/can-anyone-give-me-the-details-of-creating-a-cat-state-in-circuit-qed.1048821/ ] Hello...

Here is a picture of the problem: I honestly am pretty lost, I'm not looking for an answer, more so an idea to get me started. But here is what I was thinking: In the equation above I was trying to use: For U I am unsure how to incorporate the weight of the blocks into the u, so I am unsure...

While going through the catalogues I started to wonder, typically lower ESR caps cost more, but if I need the cap for DC smoothing , to filter out unwanted AC ripple, then I put that cap across my DC rails +-. Now so far so good. It's ability to filter out the AC ripple will be directly related...

I'm new to the forum and not sure I've chosen the right section. And while not an engineer or physicist, I'm pretty scienc-y. I've been wondering this since I was a kid listening to shortwave radio, and decided in my 60s to try once more to understand. The time broadcasts from NIST stations...

So long story short I have a power supply (DIY) for some time and on the secondary side filter/reservoir capacitors there is a small ripple (about 1v PP) of 50khz (the switching frequency of the PSU). Aside from others methods that I will implement to reduce this I am thinking of adding a shunt...

Here is the question: Here is my answer

I am getting confused by this question. Nevertheless, I tried answering this question. When I see the word pulse, it brings to my mind a pulse traveling in a rope as shown in diagram below and I cannot relate dispersion to the rope medium in which pulse is travelling. What I do know is that...

Hi, I am trying to use the SR865A lock-in amplifier to measure the frequency of a pulse of a sine wave( example: waveform below), - the sinewave signal is only ON during finite time not continuously-, I am using an external reference signal that is also a pulse of a sinewave with the same...

i am having some hard time thinking about this problem: It is basically this: Imagine a bulb and a receptor distant L from each other (at the same axis x) inside a room, the roof of the room is at a height d from the bulb and receptor. Now you are at a train moving horizontally, parallel to...

I wrote a program that uses your computer camera to monitor your Pulse Oximetry and get your heart rate. I got the program to work. I can see the heart beat in my graph. Anyhow, I set my timer interval to 0.0226757 ms which is 44100 hz. so I have a few questions, I was seeing a...

I know that from intensity autocorrelation, I simply need to divide the FWHM by 1.53 for sech2 pulses. But I can't seem to be able to find any reference on how to get pulse width from interferometric autocorrelation signal. Can someone help me?

When working with a pulsed laser (nitrogen), How can the fluorescence lifetime be longer than the pulse of the laser? Thanks for any explanations

The standard output waveform of a photomultiplier tube has a "negative" pulse, like below. Why is the amplitude negative?

Trying to discern how to measure/record infiltration of noise into my yard/home. The thread referenced is v2k. Author of thread was trying to build a v2k unit, I believe. What type of engineer is needed to record/prove continual intrusion and what equipment is needed? Would appreciate some...

I am trying to understand the reaction of a steel coil compression spring when pulsed. The spring I am interested in has the following physical characteristics: k (spring constant in pounds per inch) = 2.88 d (wire diameter in inches) = .043 n (number of active coils) = 29 D (mean diameter of...

I attempted this assignment, and scored a 5/10. The solutions are not given until a later date. I need to understand this material before I progress to the next section. The following are my attempts at the solution. The number of cycles in each pulse increases: The PD is determined by the...

Hi guys, I would like a sound for example a piece of music to be transformed into impulses. So I think I need a pulse generator that is connected to an amplifier in output and then later to a UHF transmitter, in input I would like it to receive the audio signal from my smartphone, so I thought...

Hi, I was recently attempting a question about transmission lines and I don't seem to really understand how the voltages travel through the line. Question: If we send a voltage pulse of amplitude ## V_0 ## through a lossless transmission line, what does the voltage at the output look like when...

Hi, In class I have learned how to find the Fourier transform of rectangular pulses. However, how do I solve a problem when I should sketch the Fourier transform of a pulse that isn't exactly rectangular. For instance "Sketch the Fourier transform of the following 2 pulses" Thanks in advance...

Hi, I was trying to find the magnitude of DC signal in a shifted unit pulse signal. The unshifted pulse lasts from -π to π and then it is shifted by π duration. In Method #1 I have used FT formula and ended up with magnitude of 6.2832 for DC signal, i.e. ω=0. In Method #2 I have used Laplace...

Hello to all, In a short pulse laser emission setup, can a pulse be emmited with beam length shorter than one wavelenght? (can a pulse have a duration shorter than its period?) Lets say a laser emmiter shoots a quarter cycle pulse, what would happen to this short beam? (lets supose the...

I get that a single (optical) pulse is a superposition of continuous frequency components of its spectrum, but I'm a bit confused how Fabry-Perot interference can be interpreted in time domain. In a single-frequency explanation, the idea is that the incident wave goes through multiple...

Hello, A light pulse moving bouncing between two mirrors (top and bottom) follows a vertical straight path w.r.t. to an inertial observer at rest relative to the mirrors. However, a moving inertial observer see the light pulse move in a zig-zag path as it bounced back and forth between the...

Hi, Although I'm using trigonometric form of Fourier transform, first I'd discuss both, exponential and trigonometric forms, for the sake of context. Now proceeding toward the main question and we would only be using trigonometric form. % file name...

So, I was working on autocorrelation for my pulse laser system and I started to wonder what is the difference between single wave with 400nm of wavelength and two 800nm waves overlapped. In the knowledge, I know of, is that wavelength is the length between two picks. And when it is pulse laser...

I thought work is 0 because force is applying perpendicular to the spring's moving direction. these pulses are transverse pulse since those have amplitude, and pulse is moving horizontal, which means applying force horizontally, but spring is moving vertical. So my conclusion is "because pulse...

Which of these premises is impossible or incorrect according to our current understanding of quantum entanglement? Given 2 entangled particles, p1 and p2: Observing paired particle p1 induces a change in spin on paired particle p2. There a way of detecting a change in spin on particle p2...

I have high blood pressure. My physician told me that any exercise that increases my heart rate will decrease my blood pressure. When I get angry, my heart rate increases. If increasing one's heart rate by exercise will decrease my blood pressure, it seems logical for me to think that when...

I've tried the circuit in this article. It works very well and I've obtained 2ns clear pulses at 150 V (the main issue was to find the right avalanche voltage, which turned out to be 150-160V for my 2n3904 transistor). While the basic principles of operation in this circuit is clear for me, I...

The pulse laser is converted by photo detector(PD) into electrical current. And we can see output voltage of photo detector by using oscilloscope. Now we get voltage function detected by PD. Now I need to calculate energy of pulse. But I don't know how I do it.. Is there any formula I can use??

I will use 3 way power splitter and power detector. 1. This is power splitter data sheet. In this data sheet, there are different isolation values. What does it mean?? Also in that point, I wonder definition of isolation at power splitter. 2. This is power detector data sheet. In this data...

How can I use power detectors for RF pulse detection? RF pulse has a symmetric Gaussian-like shape. Is the output of power detectors continuous line or point?

Dear all, I'm within my Ph.D. studies in laser engineering and most of the details are rather new to me. Working on short pulse systems, my advisor told me some times about the relation of the output coupler transmissivity and the outcoupled pulse length, but more as a rule of thumb. According...

Homework Statement Laser probes are being used to examine the states of atoms and molecules at high temporal resolution. A laser operating at a wavelength of 400 nm produces a 1 femtosecond pulse. Compute the mean frequency and frequency spread, ∆ν, of this laser pulse. Homework Equations c =...

Dear Sirs, I need to calculate the energy of the below pulse, as I'm new to dealing with AC I have some doubts on how to calculate it? I think I remember that in order to obtain energy one has to integrate the power, but I'm not sure. Also I'm not sure how to deal with the calculation of...

Hey all, so I’ve been learning nonlinear acoustics and have encountered a conceptual hurdle in my studies. When using a model, such as a form of the classical Burgers equation, to propagate sound waves, you generally have a “characteristic angular frequency” in the equation (often represented by...

Homework Statement If you create a 1 ms light pulse by turning a flashlight on and off, how long will the pulse take to reach the other side of the room 20m away? (in air at standard T and P) what is the length, in m, of the pulse? I realize that light has a wavelength and when you pulse it...

Hi. I hope someone can assist me? I have a sensor that is being used to detect a pulse triggered from a point on the surface of a disk rotating past the sensor. I am processing the data in real time to determine if the values would count as a pulse so that I can count up the number of...

Homework Statement A horizontal string at tension T is tapped at the midpoint to create a small transverse pulse. What happens to the pulse as time passes? If the pulse is instead created at a point other than the midpoint, what happens to it? Neglect damping. Homework Equations Speed of...

Homework Statement A uniform rope of length 12cm and mass 6kg hangs vertically from a rigid support.A block of mass 2kg is attached to the free end of the rope.A transverse pulse of wavelength 0.06m is produced at the lower end of the rope.What is the wavelength of the rope ,when it reaches...

Homework Statement Q:[/B]An ultrasound department seeks your advice regarding scans they perform to visualise and confirm foetal heart beating. They wish to know what imaging frame rate should be set in order to visualise the heart movement reliably but achieve the maximum possible reduction in...

I have the problem of making "at home" or almost, a measure of a laser's pulse energy for unit area of the target: those kinds lasts for ~ tens of milliseconds, up to some hundreds of ms and I should be able to verify that this energy "density" doesn't go beyond 40 J/cm^2 for a single pulse...

Hi guys, I am learning for an optics examination and found a picture that is supposed to show the duration of a light pulse with respect to the spectral bandwidth (appended). At this point in the lecture, we have not gone through modelocking yet, so I assume one should understand the picture...

Hi, I start at 100 MHz have 10 carrier frequencies all starting in phase at t=0 and the carrier frequencies have 25 kHz spacing. So my frequency range is 100-100.25 MHz, with 10 single frequencies equally spaced in this range. They come in phase every 4x10-5 seconds. The equation Frequency = 1...