What is Reduction: Definition and 469 Discussions

Noise reduction is the process of removing noise from a signal. Noise reduction techniques exist for audio and images. Noise reduction algorithms may distort the signal to some degree.
All signal processing devices, both analog and digital, have traits that make them susceptible to noise. Noise can be random or white noise with an even frequency distribution, or frequency-dependent noise introduced by a device's mechanism or signal processing algorithms.
In electronic recording devices, a major type of noise is hiss created by random electron motion due to thermal agitation at all temperatures above absolute zero. These agitated electrons rapidly add and subtract from the voltage of the output signal and thus create detectable noise.
In the case of photographic film and magnetic tape, noise (both visible and audible) is introduced due to the grain structure of the medium. In photographic film, the size of the grains in the film determines the film's sensitivity, more sensitive film having larger sized grains. In magnetic tape, the larger the grains of the magnetic particles (usually ferric oxide or magnetite), the more prone the medium is to noise. To compensate for this, larger areas of film or magnetic tape may be used to lower the noise to an acceptable level.

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  1. T

    Flowrate and pressure after a size reduction

    I work for a plumbing company, and I'm trying to understand things like pressure loss etc. Right now I'm trying to figure out what's shown in the attachment. It is a pipe reduction with water flowing trough it. First, is it so that the flowrate at the left end must be equal to the flowrate...
  2. H

    Solve Selective Reduction of Sn4+ to Sn2+ w/o Sn2+ to Sn

    Homework Statement Given: Sn4+ + 2e- --->Sn2+ Estandard=+0.15V For a galvanic cell under standard condition, which of the following anodic half reaction would produce at the cathode a spontaneous reduction of Sn4+ to Sn2+ but NOT Sn2+ to Sn. Pb --> Pb2+ + 2e- Sn2+ --> Sn4+ + 2e- Pb +...
  3. P

    Mastering Block Diagram Reduction: Tips and Techniques | Transfer Function Guide

    Hi, I'm having some trouble reducing a leapfrog block diagram shown in the attachment. I want to find the transfer function but I don't know how to reduce the portions which "leapfrog". I can reduce the feedback loops G1 and G4 but not too sure on where to go from there. Any help is...
  4. K

    Integration by reduction

    1. The problem Show that \int^{1}_{0}x^{m}(1-x)^{n} dx = \frac{m!n!}{(m+n+1)!} for all integers m, n \geq 0 The question is under "Reduction" topic, so I assume we solve this via reduction. 2. My attempt My attempt is as follows: Let x = cos^{2}x Then we get \frac{1}{2}\int...
  5. R

    Help to prove a reduction formula

    Homework Statement Let I_n=\int_{0}^{1} (1+x^2)^{-n} dx where n\geq1 Prove that 2nI_{n+1}=(2n-1)I_n+2^{-n}Homework Equations consider: \frac{d}{dx}(x(1+x^2)^n) The Attempt at a Solution \frac{d}{dx}(x(1+x^2)^n = (1+x^2)-2nx^2(1+x^2)^{-n-1} Integrating both sides between 1 and 0 \left[...
  6. C

    Reduction formula/Integration by parts problem

    Homework Statement The problem asks me to: Determine a reduction formula for the stated integral (See Picture and problem at: http://garciarussellchem.angelfire.com/Photo/ Please help me out with this problem. I don't understand why they do not include an extra r in the denominator...
  7. K

    Reduction of order (2nd order linear ODE homogeneous ODE)

    Reduce to the 2nd order and solve the eq. (1-x^2)y'' - 2xy' + 2y = 0 (we know that y(1) = 0) I don't know what to do here, except that I'm supposed to find y(2). I know the formulas y(2) = y(1) Int(U) dx where U = (e^(-Int(p(x)dx)) / (y(1))^2 Can I use this?
  8. T

    How Does Adiabatic Expansion Affect Ideal Gas Pressure?

    Homework Statement an ideal gas is allowed to expand adiabatically until its volume increases by 50%. By what factor is the pressured reduced?(gamma=5/3) Homework Equations P1V1^gamma=P2V2^gamma The Attempt at a Solution P1V1^gamma=P2V2^gamma v2=v1+.5V1=3/2V1...
  9. K

    Potassium Permanganate Reduction in Aqueous Buffer

    Hello everybody, I'm told that potassium permanganate is dissolved in an aqueous buffer of ammonia and ammonium at equal concentrations (1M), and treated with 1M sodium hypochlorite, the permanganate ion is reduced to insoluble manganese dioxide as the hypochlorite ion is oxiddized to...
  10. A

    How do I balance these oxidation reduction equations using the half cell method?

    I do not understand how to balance these oxidation reduction equations. These equations seem really complicated, I don't understand them. The question that i have to answer is Balance the following equations by the half cell method. Show both half cell reactions and identify them as...
  11. E

    Inverse of Matrix: Reduce Augmented Matrix [A|I] with Row Ops

    Homework Statement Find the inverse of by reducing the augmented matrix [A|I] using row operations.The Attempt at a Solution I just can't seem to get this one out, it's the last in a series of 9 similar questions and the first I am to have a hard time with. First few attempts involved...
  12. M

    Speed Reduction, Torque, high Rpms's?

    hello, i am unsure if someone will be able to help me with this? If you have a motor running at say 3000 rpm's, and the torque "needed" is more than the motor has to offer. Can you do a gear reduction to get more torque, and gain "all or most" of the lost rpm's back after reduction is made...
  13. S

    Oxidation Reduction Reactions

    Ok I'm trying to do my chemistry homework and well I'm stuck. I have the first few questions done I'm stuck on question 5 step 3, an I'm not sure the other are correct. I still have no idea how to balance equations and well here we go again with balanceing things... 1. What is the difference...
  14. N

    Solve each linear system using row reduction

    3x+3y+3z=3 x+y+z=-1 3 3 3 | 3 1 1 1 |-1 1 1 1 | 0 0 0 0 | 1 x = -y -z y = 1 Substitute y into x, x = -1 -z Let z = t, tER Then x = -1 -t, y = 1 The corresponding vector equation of the line intersection is: (x,y,z) = (-1, 1, 0) + t(-1, 0, 1) Does that look right...
  15. J

    Proving and evaluating the reduction formula for I_{m,n} with an example

    Given that I_{m,n}=\int_0^1x^m(1-x)^ndx prove that I_{m,n} = \frac{n}{m+n+1}I_{m,n-1} and evaluate I_{4,4} I set the integral up as follows: \int_0^1(x^m(1-x))(1-x)^{n-1}dx \\ = \int_0^1 x^m(1-x)^{n-1}dx - \int_0^1 x^{m+1}(1-x)^{n-1}dx\\ = \frac{m}{m-n+1}I_{m-1,n} \\ which is not what is...
  16. K

    (very) nonstandard reduction potential

    I have a question that I am familiar with, but there is no answer provided and about 1000 ways to make small mistakes. I was hoping someone could take a glance and see if any mistakes jump out. Any tips would really be appreciated. Question What is the reduction potential required for reducing...
  17. J

    How Does the Reduction Formula Simplify Integration of Trigonometric Functions?

    Show that tan^n(x) = tan^{n-2}(x)(sec^2(x)-1) \\. Hence if I_n = \int_0^{\frac{\pi}{4}}tan^n(x)dx \\. Prove that I_n = \frac{1}{n-1} - I_{n-2} \\, and evaluate I_5{/tex] My effort: I_n = \int_0^{n-2}tan^{n-2}x(sec^2x-1)dx \\ du = (n-2)tan^{n-3}x sec^2x dx \\, and v = \int(sec^2x - 1) dx...
  18. J

    How to Prove Trigonometric Reduction Using Integration by Parts

    Homework Statement Prove the following trigonometric reduction using integration by parts: \int \sin^n x dx = - \frac{\ \sin^{n-1} x \cos x}{n} + \frac{\ n-1}{n} \int \sin^{n-2} x dx 2. The attempt at a solution I tried using integration by parts by breaking up sin^n x into sin^(n-2) x...
  19. Y

    Spin reduction & bouncing ball

    Hi! I'm from sweden so my english isn't very good, well over to the physics questions: I'm qurrently making a tabletennis simulator, I'm almost done but there are two problems I haven't been able to find solutions to. In the program as it is now the spin of the tabletennis ball is...
  20. P

    Discovering the Method of Reduction of Order in ODEs: A Historical Perspective

    How did people come up with this method of finding lin independent solutions to ODEs?
  21. Mk

    50% reduction in penguin population

    I watched 60 minutes today and they used a new example of global warming in action! The journalist was talking to two arctic biologists, and the man said that there has been a 50% reduction in penguin population. That sure sounds like a big number! Is that true? I don't believe a mention of the...
  22. F

    Standard Reduction Potentials of 1/2 Cells

    Homework Statement Use half-reactions and E's to determine the result of storing a solution of CuSO4 in a tin container. Homework Equations [Table of Standard Reduction Potentials of Half-Cells] The Attempt at a Solution My question isn't exactly how to do this question. I was just...
  23. T

    Organic Chemistry Help (Sodium Borohydride Reduction)

    Homework Statement Hi all, In a sodium borohydride reaction, one of the hydride in BH4- will attack the ketone, and the O- in the ketone will bond with the BH3. This would continue until all the hydride ions are used up. My question is..what would be the driving force that makes the...
  24. A

    Lin Algebra Row Reduction (on variables)

    Homework Statement Use row reduction to show that: [1 1 1] [a b c] = (b-a)(c-a)(c-b) [a^2 b^2 c^2] Homework Equations The Attempt at a Solution So I multiplied -a by row 1 and added it to row 2. I then multiplied -a^2 by row 1 and added...
  25. M

    Superposition Diagram Reduction

    Please click the image to enlarge it http://img237.imageshack.us/img237/3605/untitlednu9.th.jpg I'm having trouble seeing how this circuit was reduced. Can anyone shed some light on it for me? My question pertains to the second solution in the image. I see that the 12k and 4k...
  26. V

    Improving Noise Reduction in Airbus Engine Nacelles

    This may be of interest to readers: http://www.flightglobal.com/articles/2007/01/23/211641/airbus-a350-xwb-set-to-be-quietest-generation-of-airliner-as-manufacturer-improves-zero-splice.htm A noise reduction engine nacelle intake. "A zero splice liner with a continuous surface and lacking...
  27. K

    How to Simplify Boolean Algebra Expressions

    I just started Digital Systems coursework and it seems our professor felt like giving us a book that has no examples and progresses the class with no examples as well. So basically we are stuck trying to learn Boolean algebra reduction with no real guidence. Great. Anyways, I'm looking...
  28. N

    Noise reduction and square wave/sine function question

    I have two simple questions but I'm not 100% on how to get the correct result. 1. "The noise is reduced by 6 dB" means its amplitude is cut to _%? How is it calculated to 50%? I try 20log(Av)... 2. Does this wave contain 30k hertz sine function? (see attachment) The answer is yes, but I...
  29. S

    Noise Reduction System: Preemphasis/Deemphasis Filter

    I know that purpose of the preemphasis filter in a noise reduction system is to increase the amplitude of the input signal at frequencies where SNR is low prior to transmitting the signal. I also know that a deemphasis filter is located at the receiving end and its purpose is to undo the effects...
  30. F

    Oxidation - Reduction with copper and zinc

    Hello, In a lab experiment, we filled 2 wells of a culture plate, one of them had 1.0 M CuSO4 and a piece of zinc metal, and the other well had 1.0 M ZnSO4 and a piece of copper metal. My question is: Which well has the reduced form of zinc and the oxidized form of copper? I know that...
  31. P

    Solve 2nd Order DE: Finding 2nd Solution w/ Reduction of Order

    Use reduction of order to find a second solution of the given differential equation t^2y"-4ty'+6y=0 t>0 y_1(t)=t^2 first I put in in the standard form y"-4/ty'+6/t^2y =0 then y= v(t)t^2 y'=v'(t)t^2+v(t)2t y"=y"(t)t^2+v'(t)2t+v'(t)2t+v(t)2 = t^2v"(t)+4tv'(t)+2v(t)...
  32. B

    Reduction of Order: Integration Explained

    hello everyone, I am stuck on this problem and i have a hard time figuring out how they went from here dw/w=-(2dx/x(x^2+1)) to here w=c(x^2+1)/x^2. i know they integrated, but can anyone show me the details of the integration along with an explanation?
  33. G

    Light Beam Reduction: Is It Possible?

    I've been wondering if it is possible for a large aperture lens, or mirror, to receive parallel rays of light, converge them, then diverge them into a smaller beam of parallel rays as they exited the optical device? If so, directing this greater flux density into a telescope matching the...
  34. L

    Boolean Reduction: Can It Be Reduced?

    (\overline a \overline b \overline c)+(a \overline b \overline c)+(\overline a \overline b d) is this reducable? I'm new to this as you may be able to tell, but I've went through this and have not found a way to reduce it, well I thought I had but then when I make a truth table the...
  35. D

    Reduce 12V DC to 1V DC: Increasing Amperage

    How can I take 12 vt dc @25 amps and reduce it to say .. 1 vt dc by raising the amperage and what would the amps be.
  36. D

    Reduction in Heisenberg uncertainty

    I am writing this on the curiosity of the results of a theoretical experiment. Imagine a photon moving thorugh space. It is moving freely through three dimentions and time. Using the Lorentz contraction we can only know approximately where it will be in 3 dimentions for a given time and speed...
  37. S

    Solving Reduction Formula: Step-by-Step Guide

    Hi, I am having trouble understanding this question, I have looked over a few examples, but I'm still confused about the process. A)Use the reduction formula to show that: \int sin^2xdx = \frac {x}{2} - \frac{sin2x}{4} + C any help would be appreciated
  38. A

    Understanding Oxidation Numbers in Redox Equations

    At this moment, I'm on balancing redox equations. I'm stuck on step one though...:redface: 1. Assign oxidation numbers to all atoms in the equation... S + HNO3 --> SO2 + NO + H2O This particular problem is an example in my Chem book so I already know the answers. I just don't...
  39. R

    Question for voltage reduction

    i have a module with microprocessor of 1.15volt sense level. when the potential is above this value it registers high and below it registers low. however the potential from the source varies from 1.3volts to 4.8volts only.nothing less than 1.15volts so all registers are high. anybody can help...
  40. G

    Investigating Vibration Reduction in Sheet Metal Using Electromagnetic Damping

    hello. can u help me with this planing execise manufacturers of sheet metal use rollers to produce the sheets. The sheets then pass along processing lines for painting. Transverse vibrations of these sheets results in a non uniform thickness of paint layers on the sheets. Electronmagnetic...
  41. S

    Reducing Agents and Standard Reduction Potentials

    1) The strongest reducing agent from those listed is: Use your book. a. Fe+3 b. Fe+2 c. Al+3 d. Al After looking at the chart of reduction potentials in my book, is it Al? 2) Select the reagent that will transform Fe+3 to Fe+2. a. H2 b. O2...
  42. X

    Reduction of quadratic form (principal axis)

    i keep getting nonzero off diagonal elements when i try to reduce to simple sum of squares, of the equation 2 x_{1}^{2}+2x_{2}^{2}+x_{3}^{2}+2x_{1}x_{3}+2x_{2}x_{3} what i have is \left(\begin{array}{ccc} x_{1} & x_{2} & x_{3} \end{array}\right) \left(\begin{array}{ccc} 2 & 1 & 0 \cr 1 &...
  43. M

    Did i do the reduction correctly? algebra type stuff

    Directions: Find all the values of x such that the given series would converge. http://cwcsrv11.cwc.psu.edu/webwork2_files/tmp/equations/fd/74dc1166ac21d3f59ee568a71eb55a1.png Here is my work: http://img203.imageshack.us/img203/9559/lastscan3jv.jpg I got it wrong but is it because i...
  44. V

    Is This Reduction Reaction Equation Correct?

    Chemistry Reduction Reaction Help Needed: MnO4- + S2- --> MnO2 + S8 I was wondering if I had done this reduction reaction equation correctly: MnO_4^-+S^{2-}\xrightarrow{}MnO_2+S_8 After going through the reduction reaction problem solving process (I think) I get this equation as the final...
  45. 0

    TI-89 Row Reduction Program Troubleshooting

    I wrote this in September so that I could do matrix row reduction on my TI-89. It works, usually, but sometimes it doesn't row reduce all the way. Any ideas what I've done wrong? Or is it just some strange quirk of the calculator? If you don't know TI-89 code, it is self explanatory except...
  46. H

    Double reduction speed Reducer

    Hi all! I am going to design a double reduction speed reducer. using spur gears. There are a few basic layout that I can choose. And which layout would be the best? Below is my consideration: All the design have the same number of bearings, so I think that the efficiency of the bearing...
  47. George Jones

    Penrose's Gravitationally Induced State Reduction

    Endnote 30.37 of Penrose's book The Road to Reality briefly outlines what Penrose calls "a more rigous justification" for his graviationally induced state reduction. The endnote concludes with "Details of this argument will be published later." Penrose also alludes to this argument in a...
  48. N

    How to get better at row reduction?

    Please don't say just practice. Any specific tips? In my class we're not allowed to use calculators, consequently I am spending all my time row reducing to find basis, dependence, etc. Frankly, I am just horrible at it, I just can't see how to get to the end. I am a bit perplexed on the...
  49. B

    ODE - Reduction of order

    Hi, say I have a second order ODE a_1 \left( x \right)\frac{{d^2 y}}{{dx}} + a_2 \left( x \right)\frac{{dy}}{{dx}} + a_3 \left( x \right)y = f\left( x \right) and I have y_H = h\left( x \right) which satisfies the DE for case of f(x) = 0. Can I always, in principle, find the general solution to...
  50. D

    Maple Maple gaussian reduction multiplying rows

    Hello, I am using maple for gaussian reduction. I have to do it row by row for 1 part > g:=swaprow(f,1,2); [ 0. 3.5 3.5 3.5] [ ] g := [ 2 -1 -5 -7] [ ]...
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