Pulse Definition and 348 Threads

I have impedance values for an electrode (used for nerve stimulation) over a wide frequency range using sinusoidal current. Now I have to calculate how much voltage I need to stimulate the electrode at a current of 5mA, using the equation (V=IR). I have to use monophasic pulse train of 5 to 10...

Ok, I used one of these in an experiment the other day but i did not fully understand it. I was setting up an RC circuit, and a pulse generator was connected to the circuit setting a repetition rate of 1ms. But a) What was the role of the pulse generator b) Is the repetition rate like inverse...

I have a laser with a short pulse duration (sub 20 fs) and i want to know how long the pulse would be after it passes through X amount of material. I don't know the refractive index of the material, but I do know its GDD over the wavelength I'm operating at. How do I go about calculating the...

Homework Statement A beam of red light entering a block of glass (n = 1.52) 10.00 miles thick will emerge 1.75 miles ahead of a blue pulse that entered at the same moment. (a) How long will it take the red light to traverse the glass? µs (b) How fast does the blue pulse travel? m/s...

This is from Physics of Atoms and Molecules - Bransden, Joachain - Section 4.1 Homework Statement Show that the average energy density in a pulse of the form (4.13) is \overline{\rho}=2\int_{\Delta\omega}\omega^{2}A_{0}^{2}\left(\omega\right)\mathrm{d}\omega Homework Equations...

Homework Statement I have attached the question as a photo. It contains two parts. Homework Equations The Attempt at a Solution For part A, is it simply Q=CV where C is given and Q is the elementary charge times 10^6? For B, I am not quite sure where to begin. Any...

Homework Statement Electrical pulses travel at about half of light speed through coax cables. Determine the pulse delay time for a cable with a length of 20 feet. Homework Equations The Attempt at a Solution I don't think this question is very hard, but I can't find any...

Homework Statement The displacement of a pulse traveling on a horizontal string is approximated by: y(x,t) = 0.05/((1.5x - 3t)^2)+1 where x and y are measured by metres. i) the velocity of propigation ii) the direction of motion iii) the maximum displacement iv) the displacement at x = 4m...

I've been intrigued lately by pulse jet engines and their simplicity. Unfortunately, they are notoriously loud and inefficient. I've come up with a design that I think may improve both of those, but before trying to actually build it, I thought it would be a good idea to try to model it first...

Homework Statement I have a rectangular train wave pulse, w(t). I needed to find the Fourier transform. My work can done can be seen in the attachment. Homework Equations My question is, is there a further way to simplify my solution. The Attempt at a Solution See attachment.

Actually i m new to electrical sciences, can anyone please explain me the working principle of a PWM?? and its applications , please provide any relevant links concerning it. Thanks in advance

Homework Statement A certain type of laser emits light that has a frequency of 5.1* 10^14 Hz. The light, however, occurs as a series of short pulses, each lasting for a time of 2.6* 10^-11 s. (a) How many wavelengths are there in one pulse? (b) The light enters a pool of water. The frequency...

I am interested in looking at the voltage component of a short (possibly nanosecond width) pulse in a coaxial cable along the cable at a given distance, Z, along the line. I am "cheating" by using the steady state Telegrapher's equation [Eq. 1] and formulating a periodic pulse approximation. It...

A transvers wave pulse travels to the right (+x direction) along a string with a speed v=3m/s. At t=0, the shape of the pulse has the form: f(x)=Ae^-(x^2/b^2), where A=3m and b=2m. a) Plot the variation of f(x) with x at t=0. b) What will the mathematical description of the pulse as a...

Homework Statement I have a question to calculate the spectrum of an infinite pulse train from a mode locked laser with each pulse having I(t) proportional to exp(t^2 / tau^2) where tau is the pulse width. tau is 50 fs, repetition rate is 100Mhz, wavelength of operation is 800nm. Please...

Homework Statement "A 1 fs pulse of laser light would be 0.3 um long. What is the range of wavelengths in a 0.3 um long pulse of (approximately) 600nm laser light?" Homework Equations (delta omega)(delta t) >= 1/2 c = (lambda)(frequency) The Attempt at a Solution I replaced (delta...

how can i "pulse" a DC current at a rate of Ghz i need to pulse a dc current through a circuit in at 2.45Ghz. astable multivibrator style How might i go about doing this

Maybe a stupid question, but anyway. The paper "Experimental Quantum Cryptography" by C. Bennettet al. discusses laser pulses of 0.1 expected photon per pulse. What does that mean physically? Is it that 90% of laser pulses are not pulses at all, containing no photons and thereby no energy? Or...

Hi, I am wondering if it is possible to generate voltage pulses (square or sinuosoidal, +/- 5V) using a computer. If yes, then how would I go about doing it? Thanks.

Homework Statement A pulse train of Gaussian shaped pulses travels in a single mode fibre. The separation (T) of the pulse centres is five times the temporal width (\Delta \tau) of an individual pulse i.e. T=5*\Delta \tau. The dispersion of the material is D=200ps/nm/km. L=0.1km, n plastic =...

Homework Statement Pulsed lasers used for science and medicine produce very brief bursts of electromagnetic energy. If the laser light wavelength is 532 nm, and the pulse lasts for 37 ps, (a) how many wavelengths are found within the laser pulse? (b) How brief would the pulse need to be to...

Hello Everyone, I am working on a system for an undergraduate project that uses pulse width modulation to power two electromagnetic clutches. I have a pic microcontroller that is supplying a PWM signal to a MOSFET that is in turn switching the ground side of my clutches. Everything seems...

This is my first post, so a little background on me: I am a senior in EE at UofL, I am currently working for a company who has given me a larger project to complete (They kept me on part time while I finish school). I have not taken any analog or digital design classes, so I fear I am in over...

Homework Statement In search for insects, a bat uses an echolocating system based on pulses of high frequency sound. These pulses are 2.0 ms in duration, have a frequency of 50 kHz, and have an intensity level of 100 dB at 1.0 m from the bat's mouth. Assume that the bat produces spherical...

Time standards are now based on atomic clocks. A promising second standard is based on pulsars, which are rotating neutron stars (highly compact stars consisting only of neutrons). Some rotate at a rate that is highly stable, sending out a radio beacon that sweeps briefly across Earth once with...

A smaller ”boom” I'm currently writing a science fiction novel, and while I'm certainly no physicist, I still aim to minimize the use of handwave devices built from unobtainium. It appears that the only propulsion system realizable with technology in use today or in the near future which...

Homework Statement Design a 555-based monostable which outputs a constant pulse 3.3s long each time a button is pressed (whether the button is pressed briefly or held down). Use a 1µF timing capacitor. Indicate all component values. What voltage should be applied to pin 5 to double the...

Hi everyone, I was working recently with a Michelson interferometer and measured the spectrum of the two pulses and see how the fringe spacing of the spectrum change as I change the position of one of the two mirrors in the interferometer, that is the time interval between the two pulses. I...

Homework Statement A wave pulse is described by the function y(x,t)=De^-(Bx-Ct)^2, where B, C and D are all positive constants. What is the speed of this wave? Homework Equations y=f(x+vt) The Attempt at a Solution y=De^-(Bx-Ct)^2 is of the form y=f(x+vt) however there is a B in...

A pulse jet has only one moving part. Nice. But what if it didn't need any moving parts? Stupid idea, right? Check out this stupid idea. They're all over the internet. http://www.youtube.com/watch?v=5U-grFuXZ9U&feature=related"

Hey guys, I'm sure I'm doing something really daft in not getting this to work, but... I want to use NDSolve to numerically solve the time evolution of a (one-dimensional) wave pulse in either the time dependent schrodinger or KG equations. My inability to do so stems from my lack of...

Homework Statement In Fig a line is used to produce a short rectangular pulse of width 12ns and peak value 800V. With S-2 open. S-1 is closed to charge the line to Vdc; after charging, S-1 is opened. Then, at t = 0, S-2 is closed to discharge the line through RR and form the pulse. Find the...

Dear All, I am making a MIDI Drum project. I want to convert the pressure sensed by piezo into pulse width with presetable setting to shift the offset level above which the output pulse will be generated. If you have any other idea to convert pressure to pulse width kindly let me know...

Hi, can anyone explain how to tune the pulse width of excimer laser? Thanks Baris

Pulse of neutrinos, E>>m, hits plasma-->charge seperation? When a large pulse of neutrinos, each with an energy much greater than the electron rest mass energy, hits some plasma does this give rise to charge separation for the plasma? Could one make a simple argument why this is true or false...

Is this method good for analyzing a pulse? Why is the averaging of the spectra good for noise cleaning? What's the criteria for defining how much windows in a set of data one should take? Anyone who clarifies this has a big thanks from me.

Hi, What is the equation for a E field of a single pulse of a laser? If that laser is shined onto say a grating spectroscope (square law detector), how can I go about deriving an expression for Intensity as a function of frequency at the output of the spectroscope? I know that the square...

I have just started to work in a ultrafast spectroscopy lab. My topic that i will be starting on next week is supercontinuum pulse compression. I just graduated with my BS Physics and have only some experience with ultrafast optics. I know the general theory of how these things work and need a...

I believe that the path of the photons will bend towards the center of mass, but I wonder what happens to the wavelength and the pulse shape while the photons are in the gravity well. The photons don't undergo any real acceleration, since they are in free fall, so their wavelengths should...

Homework Statement The NIF will use extremely powerful lasers to attempt to implode a D-T target and thus initiate nuclear fusion. One pulse of the lasers will only last for 1 nanosecond, but the total energy is expected to hit 1.8 megajoules. The wavelength is in the near ultraviolet, 350 nm...

Hi, this is the question: For part a) I did V=(L/C)-1/2=2.5x108 m/s. And then I said T=x/v where x=10m, so T=4x10-8s. For part b) V++V-=VL...since it's the first wave I suppose there wouldn't be a reflecting wave yet, so V-=0. I have an equation that says V+=[VL/2](1+R0/RL)...since...

I would like to know the difference between pulse response and impulse response. I looked for "pulse" and "impulse" on the internet and found that on some websites they had been used interchangeably. Apart from that I checked out some books and found that they use the term "impulse response"...

Homework Statement A light pulse is emitted in an inertial frame. You are moving at a constant velocity of c AWAY from the pulse, and initially 10m away from the pulse. Will the pulse reach you, and what velocity will you measure for c? Homework Equations The Attempt at a...

Hi, I would like to ask if anyone with VFD and PWM - Invertor knowledge could give me a run down on the advantages of a 36 Pulse VFD Unit in comparison to a 12 Pulse? Is the cancellation of harmonics a factor in Pulse selection? Thankyou C

Since a string pulse get amplified when it enters a less dense medium such as from the thick heavy rope to a lighter string, why does not light do the same?

Is that an official theory or just a light/naive guess (maybe mine)that, if after big bang everything expands, and we can be pretty sure every galactic center is a massive black hole -than galactics are"joining forces" to make it all(universe) back to the point the big bang happens again(and...

Hi, everyone. Can someone help me to understand pulse? What is the meaning of temporal shape? is it means the intensity distribution of the pulse is following the shape? What is the relationship between temporal shape and spectral mode distribution? Is that the Fourier transform...

Hello everyone! I recently visited the Air Force museum in Ohio and saw their Pulsejet Helicopter. It was intriguing how they attached a pulsejet to the end of each propeller tip. Since then, I’ve been wondering if two pulsejets could be used on a general aviation propeller. I’d like to...

At my business we are beginning the design of gas detection systems using IR. My question is what are the benefits of operating solid state IR sources in a pulsed mode?

Suppose the earth, moon, and an extraterrestial observer(ET) are at the corner of an equilateral triangle. The Earth observer points a laser at the moon and emits a powerful laser pulse for exactly .01 seconds. The 1,860 mile long pulse travels to the moon in about 1.3 seconds. The ET knows that...