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- - **How do I compute a sine wave**
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How do I compute a sine waveHi all,
I need to produce a sine wave and use the WaveOut APi to sound it on my sound card. I also need to compute Fast Fourier Transform to modify the Sine wave. Any ideas on where to start or get some info on this?? Cheers, Xanax. |

Re: How do I compute a sine waveXanax wrote:
> Hi all, > I need to produce a sine wave and use the WaveOut APi to sound it on my > sound card. > I also need to compute Fast Fourier Transform to modify the Sine wave. > > Any ideas on where to start or get some info on this?? This NG is about the C++ language. You'll need to look elsewhere for help on FFT's and sound API's. |

Re: How do I compute a sine waveIn comp.lang.c++
Gianni Mariani <gi2nospam@mariani.ws> wrote: >Xanax wrote: >> Hi all, >> I need to produce a sine wave and use the WaveOut APi to sound it on my >> sound card. >> I also need to compute Fast Fourier Transform to modify the Sine wave. >> >> Any ideas on where to start or get some info on this?? > >This NG is about the C++ language. So why don't you give him an example in C++? #include <iostream> #include <math.h> using namespace std; const double DegreesPerWave = 360.0; const double Pi = 3.1415926535897932384626433832795; class SineWave { public: SineWave(){Amplitude = 2.0; Resolution = 256; Wave = new double[256];}; SineWave(double Amp, int Res){Amplitude = Amp; Resolution = Res; Wave = new double[Res]; }; ~SineWave(){delete Wave;}; void MakeSinWave(); void DumpSinWave(); double Deg2Rad( double x) {return x * Pi/180.0;}; private: double Amplitude; int Resolution; double *Wave; }; int main(int argc, char **argv) { SineWave s; s.MakeSinWave(); s.DumpSinWave(); return 0; } void SineWave::MakeSinWave() { double cnt = 0.0, step = DegreesPerWave / Resolution; for ( int i = 0; i < Resolution; i++, cnt += step) { Wave[i] = Amplitude * sin(Deg2Rad(cnt)); } } void SineWave::DumpSinWave() { for ( int i = 0; i < Resolution; i++) { cout << Wave[i] << endl; } } |

Re: How do I compute a sine waveIn article <jECfb.150$1Q3.760@news.indigo.ie>, jo@fo.mo says...
> Hi all, > I need to produce a sine wave and use the WaveOut APi to sound it on my > sound card. std::sin would be the obvious way. > I also need to compute Fast Fourier Transform to modify the Sine wave. If you're starting with a sine wave, the result of an FFT is a foregone conclusion -- a sine wave is a pure fundamental, so you basically get a spike to 100% at the fundamental, and above that you'll get a tiny bit of "noise" that's basically just an artifact of the sampling. If you want to add overtones, you don't need to apply an FFT to a sine wave to start with -- you can just put in the overtones you want, and then do an inverse FFT to get your waveform. -- Later, Jerry. The universe is a figment of its own imagination. |

Re: How do I compute a sine waveThanks all that's great!!
"Jerry Coffin" <jcoffin@taeus.com> wrote in message news:MPG.19e9569167fc7214989b4b@news.clspco.adelph ia.net... > In article <jECfb.150$1Q3.760@news.indigo.ie>, jo@fo.mo says... > > Hi all, > > I need to produce a sine wave and use the WaveOut APi to sound it on my > > sound card. > > std::sin would be the obvious way. > > > I also need to compute Fast Fourier Transform to modify the Sine wave. > > If you're starting with a sine wave, the result of an FFT is a foregone > conclusion -- a sine wave is a pure fundamental, so you basically get a > spike to 100% at the fundamental, and above that you'll get a tiny bit > of "noise" that's basically just an artifact of the sampling. > > If you want to add overtones, you don't need to apply an FFT to a sine > wave to start with -- you can just put in the overtones you want, and > then do an inverse FFT to get your waveform. > > -- > Later, > Jerry. > > The universe is a figment of its own imagination. |

Re: How do I compute a sine wave"Xanax" <jo@fo.mo> wrote in message news:jECfb.150$1Q3.760@news.indigo.ie... > Hi all, > I need to produce a sine wave and use the WaveOut APi to sound it on my > sound card. > I also need to compute Fast Fourier Transform to modify the Sine wave. > > Any ideas on where to start or get some info on this?? > Cheers, > Xanax. > > Ask this question in a mathematics newsgroup (Sorry, I am too lazy to look up newsgroup names for you) |

Re: How do I compute a sine wave"Jerry Coffin" <jcoffin@taeus.com> wrote in message news:MPG.19e9569167fc7214989b4b@news.clspco.adelph ia.net... > In article <jECfb.150$1Q3.760@news.indigo.ie>, jo@fo.mo says... > > Hi all, > > I need to produce a sine wave and use the WaveOut APi to sound it on my > > sound card. > > std::sin would be the obvious way. > > > I also need to compute Fast Fourier Transform to modify the Sine wave. > > If you're starting with a sine wave, the result of an FFT is a foregone > conclusion -- a sine wave is a pure fundamental, so you basically get a > spike to 100% at the fundamental, and above that you'll get a tiny bit > of "noise" that's basically just an artifact of the sampling. > > If you want to add overtones, you don't need to apply an FFT to a sine > wave to start with -- you can just put in the overtones you want, and > then do an inverse FFT to get your waveform. > Dont confuse the newbie. |

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