# What is Pulse: Definition and 345 Discussions

In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the neck (carotid artery), wrist (radial artery), at the groin (femoral artery), behind the knee (popliteal artery), near the ankle joint (posterior tibial artery), and on foot (dorsalis pedis artery). Pulse (or the count of arterial pulse per minute) is equivalent to measuring the heart rate. The heart rate can also be measured by listening to the heart beat by auscultation, traditionally using a stethoscope and counting it for a minute. The radial pulse is commonly measured using three fingers. This has a reason: the finger closest to the heart is used to occlude the pulse pressure, the middle finger is used get a crude estimate of the blood pressure, and the finger most distal to the heart (usually the ring finger) is used to nullify the effect of the ulnar pulse as the two arteries are connected via the palmar arches (superficial and deep). The study of the pulse is known as sphygmology.

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1. ### B Redshift of a light pulse between 2 accelerating rockets

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...
2. ### Best Dosimeter for 10 ns Pulse Dose Measurement

Which type of dosimeter is best for pulse short (duration let say 10 ns) dose measurement purpose?
3. ### I Can a pulse from a laser be treated as a Gaussian?

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?
4. ### Sending drive Pulse in CQED and visualize the state by QuTip

[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...
5. ### Waves- sending a pulse across a weighted line

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...
6. ### Choosing a pulse capacitor, ESR vs reactance at frequency

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...
7. ### Why does a quick pulse of a pure tone have overtones?

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...
8. ### Choosing pulse capacitor for parasitic AC ripple suppresion

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...
9. ### Fourier transform of rectangular pulse

Here is the question: Here is my answer
10. ### Why does a traveling wave pulse get distorted?

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...
11. ### Lock-in amplifier with pulsed sinewave

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...
12. ### Special relativity, a train and a light pulse

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...
13. ### How can I improve my pulse oximetry measurements?

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...
14. ### Interferometric autocorrelation of sech^2 pulse?

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?
15. ### Fluorescence of a laser vs its pulse duration

When working with a pulsed laser (nitrogen), How can the fluorescence lifetime be longer than the pulse of the laser? Thanks for any explanations
16. ### Why does a photomultiplier tube produce a negative output pulse?

The standard output waveform of a photomultiplier tube has a "negative" pulse, like below. Why is the amplitude negative?
17. ### RE: Thread from Jan. 2021 - from voice to pulse

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...
18. ### Coil Compression Spring Reaction to a Pulse

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...
19. ### Pulse Duration (PD), Pulse Repetition Period (PRP) and Duty Factor (DF)

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...
20. ### How can I convert audio signals into pulses for radio transmission?

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...
21. ### Engineering Voltage pulse sketches for reflection on a lossless transmission line

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...
22. ### Finding Fourier Transforms of Non-Rectangular Pulses

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...
23. ### I Ω=0 and its magnitude for a unit pulse

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...
24. ### I Minimum number of cycles in a short pulse laser

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...
25. ### Is the Fabry-Perot Interference Dependent on Pulse Duration?

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...
26. ### I Light pulse path, length and shape, when bouncing between two mirrors

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...
27. ### MATLAB Approximating the inverse FT of a unit pulse using a Riemann sum

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...
28. ### Understanding Waveform & Autocorrelation in Pulse Lasers

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...
29. ### Which pulse does more work on the spring?

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...
30. ### I Communicating Via Quantum Entanglement Using Time Differentiated 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...
31. ### Medical Why some ways of increasing pulse increase BP and other ways decrease BP?

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...
32. ### Avalanche relaxation oscillator biasing resistor

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...
33. ### How to calculate pulse energy?

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??
34. ### Definition of isolation and pulse response time for a 3-way power splitter

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...
35. ### RF pulse detection with Power Detectors

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?
36. ### Relation of laser pulse length and the Output Coupler trasmissivity

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...
37. ### Mean Frequency and Frequency Spread of a Laser Pulse

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 =...
38. ### How to calculate the energy of an arbitrary pulse

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...
39. ### Angular frequency of a non-sinusoidal pulse

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...
40. ### How long does it take a 1ms pulse of light to travel 20m

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...
41. ### MHB Is there a more reliable way to track a pulse in real time?

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...
42. ### Propagation of transverse pulse on a string

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...
43. ### What is the wavelength of a pulse on a hanging rope with changing tension?

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...
44. ### Pulse repetition frequency ultrasound confusion

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...
45. ### To measure the energy density of a (brief) laser pulse

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...
46. ### Laser pulse: spectral width vs time

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...
47. ### A pulse of frequencies that start in phase - pulse period?

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...
48. ### What is the equation for calculating crystal length using index of refraction?

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!
49. ### PWM and it`s duration (picosecond pulse widths)

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.
50. T

### Understanding how electromagnetic pulse works

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...