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  • Analyzing data for noisy arrays

    - by jimbo
    Using MATLAB I filtered a very noisy m x n array with a low-pass Gaussian filter, cleaned it up pretty well but still not well enough to analyze my data. What would the next step be? I'm thinking that signal enhancement, but am not sure how to go about this.

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  • Is it any loose coupling mechanism in Objective-C + Cocoa like C# delegates or C++Qt signals+slots?

    - by Eye of Hell
    Hello. For a large programs, the standard way to chalenge a complexity is to divide a program code into small objects. Most of the actual programming languages offer this functionality via classes, so is Objective-C. But after source code is separated into small object, the second challenge is to somehow connect them with each over. Standard approaches, supported by most languages are compositon (one object is a member field of another), inheritance, templates (generics) and callbacks. More cryptic techniques include method-level delagates (C#) and signals+slots (C++Qt). I like the delegates / signals idea, since while connecting two objects i can connect individual methods with each over, without objects knowing anything of each over. For C#, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); object1.SomethingHappened += object2.HandleSomething; In this code, is object1 calls it's SomethingHappened delegate (like a normal method call) the HandleSomething method of object2 will be called. For C++Qt, it will look like this: var object1 = new CObject1(); var object2 = new CObject2(); connect( object1, SIGNAL(SomethingHappened()), object2, SLOT(HandleSomething()) ); The result will be exactly the same. This technique has some advantages and disadvantages, but generally i like it more than interfaces since if program code base grows i can change connections and add new ones without creating tons of interfaces. After examination of Objective-C i havn't found any way to use this technique i like :(. It seems that Objective-C supports message passing perfectly well, but it requres for object1 to have a pointer to object2 in order to pass it a message. If some object needs to be connected to lots of other objects, in Objective-C i will be forced to give him pointers to each of the objects it must be connected. So, the question :). Is it any approach in Objective-C programming that will closely resemble delegate / signal+slot types of connection, not a 'give first object an entire pointer to second object so it can pass a message to it'. Method-level connections are a bit more preferable to me than object-level connection ^_^.

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  • Qt, Color Picker Dialog?

    - by high6
    Is there a color picker dialog for Qt like the following? Also it needs to have a OnColorChanged signal which is called when ever the selected color changes. I want to give a live preview when they are changing the colors, that is why. Using google I could only find this one that was a triangle in side of a circle and personally I think it looks ugly.

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  • No clock with FTDIchip FT2232 MPSSE mode

    - by Simi
    Hello, I'm trying to write/read to an extern device connected to a FTDIchip FT2232 MPSSE mode using SPI. I'm using the SPI function given by FTDI for Labview. I'm doing this: Open_Device - Init_Device - Write/Read - Close_Device The problem is that I don't have a clock signal on the scope when I try to read/write. Do you have a solution? Thanks

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  • GNU Emacs is crashing with -nw

    - by Jack
    When I run emacs with -nw option, the emacs really open, but I can't do more nothing. As if the user input is blocked and no keyboard signal is received and/or interpreted. I've tried run without load .emacs file and some other behaviors: emacs -nw -Q --no-desktop --debug-ini foo.c But makes no difference and strangely the GUI-version(using Gtk) is working fine. My gnu-emacs version is GNU Emacs 23.3.1 Any help to help to fix it is very appreciated.

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  • plotting stem with a continuous line

    - by Abruzzo Forte e Gentile
    Hi All I need to plot a stem plot of my signal using python and matplotlib. I saw the example and the code but the line connecting the black big dot and the x-axis is not a continous line. Do you know whether is possible and how to get a straight line instead? Thank you very much AFG #!/usr/bin/env python from pylab import * x = linspace(0.1, 2*pi, 10) markerline, stemlines, baseline = stem(x, cos(x), '-.') setp(markerline, 'markerfacecolor', 'b') setp(baseline, 'color','r', 'linewidth', 2) show()

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  • What are common uses of condition variables in C++?

    - by jasonline
    I'm trying to learn about condition variables. I would like to know what are the common situations where condition variables are used. One example is in a blocking queue, where two threads access the queue - the producer thread pushes an item into the queue, while the consumer thread pops an item from the queue. If the queue is empty, the consumer thread is waiting until a signal is sent by the producer thread. What are other design situations where you need a condition variable to be used?

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  • windows mobile - connection link failed

    - by Glenn
    Windows mobile 6.1 device, attempting to connect via a mobile network and we sometime see the message "Connection Link failed". Can anyone verify what this actually means, I'm beginning to think it relates to signal from the mobile carrier but does anyone have any other ideas?

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  • event handling in C++

    - by Max
    Hi. I'm writing a game in C++, and I'm trying to get it to recognize keyboard and mouse events. Google tells me that boost.signal is suitable for event handling, but none of the code samples or tutorials I've found tell me how to associate a keypress or mouseclick with a function. Can anyone shed any light on this?

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  • Why do toast notifications die if delayed?

    - by ubershmekel
    I'm not sure this is the exact cause of my problem but I'll explain the 2 symptoms I noticed: If I put a break point on a Toast.makeText(..).show(), step over, then wait a few seconds before running, the toast will never appear. I have a location callback that tries to show a toast, but it never appears. Maybe I'm doing something else wrong, this is the line in question in my open source distress signal app. Any help or pointers would be appreciated, --uber

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  • C++ Win/Linux thread syncronization Event

    - by JP
    Hello I have some code that is cross-platform by unsing #ifdef OS, I have a Queue protected by a CriticalSection on Windows, and by a pthread_mutex_t on Linux. I would like to implement a Wait(timeout) call that would block a thread until something has been enqueued. I though about using WaitForSingleObject on windows but it don't seem to support CriticalSection. Which Win32 and which Linux functions should I use to Wait and Signal for a condition to happen. Thank

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  • Linux signals with extra information parameter

    - by Tester
    I was to have some extra information in the callback to sa_sigaction handler, it does not seems possible. So I was wondering if you could suggest me alternatives. Basic requirements: Function A raises an signal/event with a pointer to a struct Handler function tackles the event. The handler function would only be called on an event and a loop to wait for the event, as in select() , is undesirable. TIA

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  • How can I know when QProcess wants to read input?

    - by mpcabd
    I'm implementing a compiler in my Compilers class, I'm using Qt & C++. After I have generated the machine code from the source code, I'm executing the virtual machine that will execute the call. I'm facing a problem here, I'm using readyRead() signal to get output from the virtual machine, but how can I know that the virtual machine wants to read data from the user? I wanna show the user an input dialog each time the machine asks for input.

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  • Is there a way to implement OnReady() callback in Qt4?

    - by lilo
    I want to do something which will access network when a QMainWindow is ready. I suppose I should not do it in the constructor, so I try to find a signal the widget will get and try to implement something like a OnReady() call back in other UI library. But I still can not find a way to do this. Thanks a lot in advance.

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  • Getting Frequency Components with FFT

    - by ruhig brauner
    so I was able to solv my last problem but i stubmled upon the next already. So I want to make a simple spectrogram but in oder to do so I want to understand how FFT-libaries work and what they actually calculate and return. (FFT and Signal Processing is the number 1 topic I will get into as soon as I have time but right now, I only have time for some programming exercises in the evening. ;) ) Here I just summarized the most important parts: int framesPerSecond; int samplesPerSecond; int samplesPerCycle; // right now i want to refresh the spectogram every DoubleFFT_1D fft; WAVReader audioIn; double audioL[], audioR[]; double fftL[], fftR[]; ..... framesPerSecond = 30; audioIn= new WAVReader("Strobe.wav"); int samplesPerSecond = (int)audioIn.GetSampleRate(); samplesPerCycle = (int)(audioIn.GetSampleRate()/framesPerSecond); audioL = new double[samplesPerCycle*2]; audioR = new double[samplesPerCycle*2]; fftL = new double[samplesPerCycle]; fftR = new double[samplesPerCycle]; for(int i = 0; i < samplesPerCycle; i++) { // don't even know why,... fftL[i] = 0; fftR[i] = 0; } fft = new DoubleFFT_1D(samplesPerCycle); ..... for(int i = 0; i < samplesPerCycle; i++) { audioIn.GetStereoSamples(temp); audioL[i]=temp[0]; audioR[i]=temp[1]; } fft.realForwardFull(audioL); //still stereo fft.realForwardFull(audioR); System.out.println("Check"); for(int i = 0; i < samplesPerCycle; i++) { //storing the magnitude in the fftL/R arrays fftL[i] = Math.sqrt(audioL[2*i]*audioL[2*i] + audioL[2*i+1]*audioL[2*i+1]); fftR[i] = Math.sqrt(audioR[2*i]*audioR[2*i] + audioR[2*i+1]*audioR[2*i+1]); } So the question is, if I want to know, what frequencys are in the sampled signal, how do I calculate them? (When I want to print the fftL / fftR arrays, I get some exponential formes at both ends of the array.) Thx :)

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  • Custom QAction/QMenu for mouse button detection

    - by voodoogiant
    I'm trying to create a popup menu, where I can detect the mouse button that was pressed for a given item. I've created a custom QAction already to build my QMenu, but the triggered signal when the menu item is pressed doesn't provide a QMouseEvent for me to query the button pressed. Also, I'm setting the a status tip for each QAction, which appears in the status bar when I mouse over it, but it stays even after I close the QMenu. Is this normal behavior?

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