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    FFT Low Pass Filtering methods

    First off, let me announce that I know very little about DSP, and I'm coming at this from a mathematical perspective so my language may be....different.... I have a set of data stored in a 3D array of size 64x128x128 which I would like to decompose into "large scale" and "small scale"...
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    Applications of Bernoulli's principle

    I'm giving a short presentation on the Bernoulli principle pretty soon and I'd like to solicit some suggestions from the community. So far I've determined that I'd like to cover: Aerofoils, astrophysical jets, and a topic that I recently came across... That one is a combination of...
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    Taking the curl of a vector field in matlab using Fourier transforms

    I've been given a data set which is stored in a 3D array and I need to do some analysis of it. One part of the analysis is to take the curl, and I've been told that this will be easier to do if I take a Fourier transform first. This is because the curl in k-space is just ikxA. Now, I've...
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    FFTW questions

    I'm working with Intel's FFTW libraries and I have a few questions about phases. First off, as a test example I'm taking the fft of a gaussian pulse. I've set it up so that the pulse is centered at x=5, with x ranging from 0 to 10. I plot the initial pulse, so far so good, its the...
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    Fourier transforms in Matlab

    I'm taken a Fourier transform of some equations and solving them using Matlab's ode45 routine. Next I want to inverse fft them back to spatial coordinates and I have a few questions about how Matlab does this. To give a concrete example of my problem I start with the initial conditions...
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    Popping through speakers over HDMI

    I've had the setup for a little over a year working fine, now it makes popping sounds through the speakers when playing anything over HDMI. I have a Samsung LN40A550 TV with a Samsung HT-AS720S receiver with the speaker set that came with it. The devices connected to it are a PS3 and a WD...
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    Differential Equations with constraints - Lagrange multipliers

    Once again digging up old math problems. I have a set of equations that look roughly like the incompressible Navier-Stokes equations. (Wish this forum supported Tex...) \partial_t u = RHS + \nabla P \nabla \cdot u = 0 I haven't actually tested this in LaTex so don't know if it works...
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    Help with some subtleties of Runge-Kutta 4 method

    I've been trying to solve a set of coupled differential equations for a while. The first 6 are 1st order ODE's in time, with no explicit time dependance. The last equation is a second order in space, and is a constraint equation. I'm programming in Fortran 90 with a sideproject involving...
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    Help with Maple/Matlab/Mathematica

    I have a set of 2 coupled differential vector equations. When I expand them all out they form a set of 6 coupled 1st order DE's (they are complex). This is a bit of a rehash of an earlier post from way back when. Long story short, I've been working on solving these equations numerically...
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    Volume of a spere with 2 sections taken out of it

    Hey guys I'm working on a project and I've run into a snag and I haven't done vector calculus in years. Here's the problem: Picture a sphere partially filled with liquid up to some height, now slice the sphere in the vertical plane at some depth. Effectively a spherical cap oriented...
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    Solving coupled Diff Eqs with Runge Kutta

    I have a set of 6 coupled differential equations, the variables are U_x, U_y, U_z, b_x,b_y,b_z and the differential is over time. For brevity I won't post the equations themselves but they are effectively: db/dt = x*b + i*u and du/dt = x*u + i*b +dQ/dx Where the bold means vector and i...
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    USB to Parallel Adapters for a DDS evaluation board

    I'm currently building a device which has 8 or so direct digital synthesizers from analog devices (AD9858 for those of you who are interested). The boards only have a parallel interface which makes talking to 8 of them at once difficult, also the software for them is a windows app only and I...
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    Odd computer behavior, can't pin it down

    First here's the hardware: E6420 at stock speeds (was overclocked but behavior the same at all speeds) -Xigmatec cooler on it Gigabyte DS3R revision 1.0 newest bios 2x1Gb Corsair 667 2x512Mb Mushkin 667 300Gb Maxtor as a data drive 160Gb Seagate as the OS drive both SATA XFX 7800GT...
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    Question about whats going on in a long SVGA cable

    Whilst procrastinating at work, I noticed that the three colours on the monitor for the security cameras in the store are all separated. What this means is that there are 3 images in red and green on top of the regular picture. The image is after a couple hundred feet of SVGA cable. Some of...
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    How much can my H2O cooling provide

    I am seriously considering upgrading my venerable d805 to a newer processor. I was wondering if my Swiftec apex premium would be able to keep up with an OC'd Q6600. Its a single 12cm rad with a push-pull fan config mounted inside the case on the front intake. My loop is res->pump->rad->cpu...
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    Direct3D is foobar

    I recently got a virus on my compy and managed to get it off after a lot of trouble. The registry was played with by a few programs and the end result is that direct3D won't load anymore. Whenever I try to load anything with graphics I get "The application failed to start because d3d8thk.dll...
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    Formatting issues on a SATA drive

    My girlfriend just tried to reformat her computer. She uses a 120GB IDE hard drive with a partition to install to, she then has a data drive which is a 320 GB SATA hard drive. The Install went ok, except the version of windows is one without a service pack and so couldn't recognize the 320...
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    Sound Card Troubles

    My girlfriends computer recently crashed and she had to hard reboot. When she did, windows went through the whole "detected new hardware" thing. Turns out its the sound card (an audigy 2) that was "found". I told her to reinstall the drivers but the drivers say that the proper hardware was...