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. C

    Engine lubricant temperature reduction

    I need to reduce the lubricant temperature in a motorcycle engine.? I've been allotted this project in a motorcycle company in India in which I need to reduce the average temperature to which a lubricating oil gets heated up, in an engine for one of their models. Now I did see the flow path of...
  2. Z

    Model Reduction and Substructuring in Dynamics, CMS

    Dear engineers and physicists, I would like to ask you a question about Component Mode Synthesis (CMS), which is the topic of my bachelor thesis. My primary resource is the classical AIAA article "Coupling of Substructures for Dynamic Analyses: an Overview" by Prof. Craig. For now I am...
  3. S

    Simply Typed Lambda Calculus question - Beta Reduction

    Homework Statement Under the assumption that BETA is a closed term show that (λx.α)(β) and α[x→β] are logically equivalent. Homework Equations I'm sure I have to use β-reduction but I'm not sure how in this case: ⊢(λx.x)(β→α[x→β] The Attempt at a Solution
  4. H

    Plotting & Verifying Air Pressure Reduction over Time

    I am trying to complete the following question: By pumping the air pressure in a tank is reduced by 15%/second. The percentage of air pressure remaining is fiven by the formula. p=100(0.85)^t Plot p against t for 0 < t < 30s. Deternine the rate of change at 5s & 10s. I have plotted...
  5. D

    Possible Expressions for Matrix Rotation Reduction

    I'm wondering if the following is possible. Consider some inertial coordiante system x, y, z, and a rotating coordiante system p, q, r defined through matrix rotations as follows. \begin{pmatrix} p \\ q \\ r \end{pmatrix} = R_1(\theta_1(t)) R_2(\theta_2(t)) R_3(\theta_3(t))...
  6. Sudharaka

    MHB Method of Reduction of Order and Variation of Parameters

    Hi everyone, :) One of my friends gave me the following question. I am posting the question and the answer here so that he could check his work. Question: This question concerns the differential equation, \[x\frac{d^{2}y}{dx^2}-(x+1)\frac{dy}{dx}+y=x^2\] and the associated homogeneous...
  7. T

    How to use standard reduction potential table

    Hi, can someone please explain to me how I can identify which is the oxidation half and which is the reduction half of a redox reaction. I have read on the internet that the oxidation half is the highest up the table between the two then why doesn't it work for: (Ca^2+) + 2Br → Ca + Br2...
  8. M

    Very basic question regarding reduction drives.

    Hi! In a speed-reduction drive, because the power transmitted is almost constant, as the speed decreases the torque increases. Is this reduced rear wheel/shaft speed the same when the loaded condition is considered? Let's assume that the prime mover is rated to produce 1.4 mN torque at...
  9. F

    Control Systems, Reduction, Stability,Characteristics and Overshoot

    Homework Statement Welding robot is defined by the block diagram attached/ excuse the paint work. (hope that worked) find: a)maximum value of K required to achieve stability. b)roots of the characteristic equation, at half the maximum K value. c)estimated percentage overshoot, if the...
  10. 1

    Reduction of Order not giving a second solution

    Homework Statement (x-1)y'' - xy' + y = 0, y=e^x is a solution Homework Equations The Attempt at a Solution Assume the second solution is of the form ve^x, where v' = (y^'2)e^-int[-x/(x-1)] So v' = e^(-2x)e^(x+ln|x-1|) = e^(ln|x+1|-x) Then, this second solution must be...
  11. M

    Automating Reduction by a Varying Modulus

    Hey guys, I'm doing some experimenting recently with some primality tests, and I need help figuring out how to automate the following: Given an even number N, divide by 2k (k \in \mathbb{N}). If N/2k is an integer, reduce mod 2k+1. (If N/2k is not an integer, simply move on to the next one.)...
  12. S

    Reduction of the electronic wave vectors (K points)

    Hello, I have come across this sentence in a paper: "For a metal, the introduction of a finite temperature T can be of a more technical use: the Fermi surface of the system is no longer a sharp feature in the Brillouin zone, and the number of electronic wave vectors "k points" needed to...
  13. Z

    Reduction of Order to find 2nd solution of DE

    Homework Statement t^2y''-4ty'+6y=0 t>0, y1(t)=t^2 find the 2nd solution using method of reduction of order.Homework Equations The Attempt at a Solution Let y=v(t)t^2 y'=2tv+v't^2 y''=2v+2tv'+v''t^2+2tv' put in back into eq and solving reduces to (checked it twice) t^4*v''=0 v''=0 Then I...
  14. J

    D.E.: Reduction of Order: Non-shortcut method question

    I don't know what to do with the x^3*e^x on the left side of the page. In the example the instructor gave for a different problem, you couldn't solve for x. In this problem you can so what does that mean I need to do with it?
  15. J

    D.E. Reduction of Order: Can't integrate

    see image http://i.imgur.com/OCj7Q5f.jpg
  16. J

    D.E. Reduction of Order: Stuck on step 2

    When you do the 1st and 2nd derivatives of y2, you're supposed to get u' and u'' in your answer. My question is why can't you do it the way I've started to do it? Or, why are my answers for y2' and y2'' wrong? http://i.imgur.com/OarDiuW.jpg
  17. M

    Finding a Second Linear Solution using Reduction of Order Method for ODEs

    Homework Statement Use the method of reduction of order to find another independently linear solution y2(x) when given one solution. x^2y'' - x(x+2)y' + (x+2)y = 0 y_1(x) = x The Attempt at a Solution Hopefully y2(x) will take the form of v(x)y1(x) or I have no idea how to solve the ODE...
  18. B

    Is My Solution to the Reduction of Order Problem Correct?

    I think I have this right, its just its an online assignment and I don't want to lose any points on it.(1/4 my grade) Question: Find y2 if y1= x^(-1) and the equation: x^2y"+3ty'+y=0. I solved(using Abel's) for it: ln(x)/x but I am not entirely sure. Wondering if I am spot on or...
  19. G

    Voltage reduction to match micro grid-tie inverter limits

    A panel put out over 30.7 volts, say 34 volts and I have a micro-inverter that require a voltage of 11-30 to work. Other than shading some of the panel, is there a way to half the voltage from the panel without as much loss from shading some of the cells to work the inverter?
  20. S

    Oxidation and reduction problems

    When something is oxidized, it gains oxygen, loses hydrogen or loses electron. However, if the substance gains something else other than oxygen then it won't be considered oxidation anymore? For instance H+ +OH- -->H2O so in this case it seems that the H+ gained oxygen from OH- but actually the...
  21. S

    Reduction formula regarding binomial (1+x^2)^n

    Homework Statement prove the following reduction formula, n>0 ∫((1+x^2)^n) dx=(x(1+x^2)^n)(1/(2n+1)) +2n/(2n+1)∫(1+x^2)^(n-1) dx Homework Equations none The Attempt at a Solution one of many attempts, i get close, but no cigar. Huge blow to the calculus ego. Any help would be greatly...
  22. C

    Ligands and lowering reduction potential

    Hi I have a question I was wondering if y'all could clear up. Let's say I have two metal cations, Iron (III) and Manganese (II). Will binding them to an anionic ligand lower their reduction potentials (making each a better redundant) and if so why? Is it because the anionic charge of the...
  23. C

    Deriving relation between angular momentum reduction by torque

    Friction causes a torque that opposes angular momentum. It gets reduced. how can we derive a relation connecting these. friction starts with maximum and becomes zero. angular velocity and its corresponding momentum decreases maximum in the beginning and increases towards the end. the radial...
  24. H

    [Electrochemistry] Reduction potential, keq and kd calculations

    Homework Statement A) Calculate the reduction potential for the reduction of E \cdot Fe^{3+} (aq) by Fe^{2+} B)What is the equilibrium expression, equilbrium constant, and K_{d} for E \cdot Fe^{3+} (aq) Known: Fe^{3+} (aq) + e \rightarrow Fe^{2+}(aq) \hspace{15pt} E = 0.22 V E \cdot...
  25. T

    Understanding Fractional Reduction: Solving Complex Fractions with Ease

    Hi, this seems like the right section to post, I have a few questions, three fractions that I know the answer for but I just can't figure out how they were arrived at (the middle step). The only way I can think of solving them is expanding it all out etc. which would result in a 100 term cubic...
  26. L

    Calculating bullet velocity reduction over time

    I'm developing a 2 Dimensional iOS war game, so think guns bullets damage hit points etc. I'm trying to write a function that calculates the Velocity of a bullet at a certain distance, so that I can calculate the force of the bullet at a certain distance. So let's say the that Rifle A is...
  27. T

    Why does reduction of order work for linear ODEs?

    This is not a homework problem, I just want to understand some theory behind this mathematical method. Specifically, if we know that one solution is y1(t), then why is the second solution in the form y2(t) = v(t) * y1(t)? Where v(t) is the function that you need to solve for. Why does...
  28. T

    Simple Differential equation with reduction of order

    use method of reduction of order to find second solution: t2y''-4ty+6y = 0 , y1(t)= t2 Attempt: So I've done all the steps, up to the substitution, but I'm having problems with what appears to be a simple linear equation but I can't solve it: Any ways, with w = v' I arrive at...
  29. A

    Automotive Need Help Calculating MPH Increase From Reduction in Drag Coefficient

    I am new to the forums and need help with something. I have been using a spreadsheet that somebody else made in order to help me design an electric motorcycle. I have been inputing my own data using most of his calculations and I have noticed that he did not calculate any aerodynamic parameters...
  30. D

    MHB Solve Reduction of Order Legendre Polynomials Equation

    Legendre polynomials I have one solution to $(1-x^2)y''-2xy'+\lambda^2 y=0$ and that is $$ \lambda^2a_0 - (2 - \lambda^2)xa_1 + 2a_2 + 6xa_3 + \sum_{k = 2}^{\infty}\left[a_k\left(\lambda^2 - k - k^2\right) + a_{k + 2}\left(k^2 + 3k + 2\right)\right]x^k = 0. $$ From this equation, we can conclude...
  31. L

    2nd order Differential Eq. - Reduction of Order

    I have a problem with differential equations - 2nd order - reduction of order my problem is as follows: (x − 1)y" − xy' + y = 0 , x > 1 ; y_1(x) = e^x solving this type of diff. eq. says to use y=y_1(x)V(x) which gives me y=Ve^x differentiating y gives me y'=V'e^x & y''=V''e^x...
  32. L

    Difference between Recursion and Reduction formulas in Integration?

    This post received no response. Can be deleted. Thanks.
  33. L

    What's the difference between Recursion & Reduction in terms of Integration?

    Homework Statement My book talks about the "reduction formulas" for evaluating trigonometric integrals by parts. However, is this the same thing as "recursive" formulas for integration by parts, a term which is not mentioned in my calculus book? Homework Equations The Attempt at...
  34. L

    Integration by parts: Reduction Formulas

    Homework Statement Are there any sample problems worked out for trig functions of higher powers which are integrated by reduction formula? Like cos^8 or cos^10 or even just cos^6 or maybe?
  35. Saitama

    Solving Birch Reduction Homework

    Homework Statement Homework Equations The Attempt at a Solution I thought the answer should be this: But in the answer key, its something else. In the answer key, it is: I don't understand why the left ring doesn't react.
  36. G

    Differential Equations. Reduction of Order. Calc IV.

    Homework Statement (x2+2y')y''+2xy'=0 with initial conditions of y(0)=1 and y'(0)=0 Homework Equations reduction of order, and exact equations.. The Attempt at a Solution let y'=p and y''=p' Giving: (x2+2p)p'+2xp Let M=2xp and N=(x2+2p) So, Mp=2x and Nx=2x Therefore, they are...
  37. M

    Static condensation or Guyan reduction

    Hey all, I was going through a few video lectures on youtube. To be specific, this is the video I watched. Now, the professor in the video talks about Dynamic reduction techniques and puts Guyan reduction in that category. For a fact, Guyan reduction is also called Static condensation and...
  38. R

    Fraction reduction, euclid's algorithm

    Homework Statement reduce the fraction \frac{943578}{1978935} to its lowest terms using Euclid's algorithm The Attempt at a Solution I start with finding the gcd of these two numbers using E.algorithm 1978935=943578*2+91779 942578=91779*10+25788 91779=25788*3+14415 25788=14415*1+11373...
  39. U

    Automotive Some ideas for a CO2 emission reduction device to be attached to cars

    Hi, I and my team-mate have proposed an idea to develop a CO2 emission reduction device to be installed in automobiles. We have mentioned that it will operate on the principle of 'active adsorption of CO2 on charcoal'. However, although the basic scientific principle is pretty simple...
  40. C

    Evaluation of reduction formula

    Homework Statement Given ∫xn2xdx= 2/ln(2) -n/ln(2)∫xn-12xdx, for n≥1 find ∫x32xdx all integrals have limits 1and 0. Homework Equations The Attempt at a Solution doing this I get... 2/ln2 -3/ln2(2/ln2-2ln2)(2/ln2 -1/ln2)(2/ln2-1/ln2) but this just gives me 0 I...
  41. F

    Decision making based on entropy reduction

    Hello guys, I just registered on this forum, so I hope you can help me with some differential entropy stuff. So I have made the attached pdf file (it's a bit messy, sorry) that demonstrates a toy version of the problem I'm trying to solve. Thing is I'm quite new to information theory, so...
  42. V

    How to calculate the velocity reduction in pipes

    I have a big pipe with known diameter, length and velcity at big pipe. There are two pipes dividing form the big pipe with varing diameter and length. 1) How to calculate velocity of water in these two pipes? 2) If I add one more pipe of known length and diameter, what would be the velocity...
  43. G

    Does time dialation cause mass reduction in GR?

    I love Physics! I've been thinking about if... you were in a room with a window, bouncing a ball... and you were looking at another building where you could see a room with a person bouncing a ball, but ... their time was moving at half speed (Caused by gravitational time dilation only ( not...
  44. sunrah

    Nonlinear DE Reduction for \ddot{y} = - \dot{y} - y -sin(y)

    Homework Statement \ddot{y} = - \dot{y} - y -sin(y) Homework Equations The Attempt at a Solution to reduce the order I need to find a solution y1. it seems to me the only obvious solution is y1 = 0 but i can't use this to do a reduction can i
  45. ElijahRockers

    Method of reduction of order

    Homework Statement Solve the following using the method of reduction of order. 4x^2y''+y=0 y_1=\sqrt{x}lnx Homework Equations y_2=v(x)y_1 v(x) = ∫ (e^(-∫P(x)dx / y_1) Sorry if that's tough to read, couldn't figure out the latex for it, but it's supposed to be a forumla for...
  46. R

    Simplify Block Diagrams: Finding Overall Transfer Equation for Homework

    Homework Statement finding the overall transfer equation Homework Equations not sure which equation to use The Attempt at a Solution unsure how to solve this, don't know where to start off from
  47. J

    Validity of Reduction Formula

    Homework Statement If In denotes \int_0^∞ \! \frac{1}{(1+x^2)^n} \, \mathrm{d} x Prove that 2nI_{n+1} = (2n-1)I_n, and state the values of n for which this reduction formula is valid. Homework Equations The Attempt at a Solution I_n=\int_0^∞ \! \frac{1}{(1+x^2)^n} \, \mathrm{d} x =\int_0^∞...
  48. G

    Paralleling capacitors effect on total esr reduction.

    Hi and thanks for taking the time to read this post. I am trying to decide component values for 2 parallel capacitors, in an effort to reduce esr, which will be for use as power supply smoothing capacitors to be placed after the bridge rectifier. After examination i noticed that consumer...
  49. M

    Reduction of a ketone using zinc in acetic acid

    I'm going to be giving a 1st year student chemistry tutoring so I'm going over some of his past exam papers to make sure I know all the stuff but I'm already at a question I can't do: http://img571.imageshack.us/img571/5716/26705030.png So from the formula, I can see that the degree of...
  50. S

    Finding y_2(x) using Reduction of Order

    Homework Statement Find y_2(x) given that y_1(x) = e^x for (x – 1)y'' – xy' + y = sin x. Homework Equations Reduction of order method. The Attempt at a Solution My attempt is attached as MyWork.jpg. Is what I did so far 100% correct? Assuming it is, what do I do now? Any help in...
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