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biquad\nLightweight Bilinear Transform (BLT) filter implementations for DSP in sensor fusion and audio.\n\nThis is mostly a toy library. For production ready filtering see [pctl](https://github.com/brandondube/pctl) by brandondube.\n\nBelow is an example of usage and the resulting plot:\n```go\nconst (\n    pi = math.Pi\n    // working frequency. The frequency that matters (we wish to keep it)\n    f0     = 2.\n    fnoise = 4.\n    fs     = 100.   // Sampling frequency.\n    N      = 100    // amount of sample points\n    ts     = 1 / fs // sampling period\n)\n// We generate waveform data composed of a \"working\" frequency and a \"noise\" frequency\ndata := make([]float64, N)\nfor i := 0; i \u003c N; i++ {\n    t := float64(i) * ts\n    data[i] = math.Sin(2*pi*f0*t) + math.Sin(2*pi*fnoise*t)\n}\nsignal := biquad.MakeSignal(fs, data)\nlp, err := biquad.NewLowPass(fs, f0, 1)\nif err != nil {\n    panic(err)\n}\n\nfiltered, err := lp.Filter(signal)\nif err != nil {\n    panic(err)\n}\np := plot.New()\nls, _ := plotter.NewLine(signal)\nlf, _ := plotter.NewLine(filtered)\nlf.Dashes = []font.Length{0.1 * font.Centimeter, 0.1 * font.Centimeter}\np.Add(ls, lf)\np.Legend.Add(\"original signal\", ls)\np.Legend.Add(\"filtered signal\", lf)\nerr = p.Save(30*font.Centimeter, 15*font.Centimeter, \"out.png\")\nif err != nil {\n    panic(err)\n}\n```\n![Low Pass example usage](./_assets/example_lowpass.png)\n\u003e Low pass filter applied to a composite signal to effectively cancel out the higher frequency noise.\n\n\n## Bode plots\nThere is some semblance of a Bode plotter for discrete time (z transfer) functions under `bode.go`. \n\nThis is the result of plotting the Bode of a notch filter:\n\n![Notch filter Bode plot](./_assets/notch_f0=4.png)\n\u003e Notch filter Bode Plot.\n\nThis API is not yet exposed because I'm still unsure of what exactly is being plotted (units). If you're interested please help out! I'll be looking at issues.\nBelow is the code for the Bode Plot:\n```go\nconst (\n    fs = 100.\n    ts = 1 / fs\n)\nlp, err := NewNotch(fs, 4, 1)\nif err != nil {\n    t.Fatal(err)\n}\nH := lp.getH()\nplotBode(\"notch_f0=4.png\", ts, H)\n```\n","funding_links":[],"categories":[],"sub_categories":[],"project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fsoypat%2Fbiquad","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fsoypat%2Fbiquad","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fsoypat%2Fbiquad/lists"}