Example: FIR filter in C++

The following example shows how to apply FIR filter to audio data using KFR framework.

#include <kfr/all.hpp>

using namespace kfr;

int main(int argc, char** argv)
{
    // static array (like std::array) to hold the taps
    univector<double, 15> taps;

    // initialize window function
    // we pass tap count to window_hann function
    // window_hann does not calculate window functions
    // but creates object representing hann window
    expression_pointer<double> hann =
        to_pointer(window_hann(taps.size()));

    // FIR filter design using window method
    // frequency = 0.02
    // true means that taps will be normalized
    fir_lowpass(taps, 960.0 / 48000.0, hann, true);     

    // show filter frequency response using dspplot python library
    // dspplot must be installed before launching this example
    plot_show("fir_lowpass_hann", taps, "title='15-point lowpass FIR, Hann window'");
}

#include <kfr/all.hpp>

using namespace kfr;

int main(int argc, char** argv)

{

// static array (like std::array) to hold the taps

univector<double, 15> taps;

// initialize window function

// we pass tap count to window_hann function

// window_hann does not calculate window functions

// but creates object representing hann window

expression_pointer<double> hann =

to_pointer(window_hann(taps.size()));

// FIR filter design using window method

// frequency = 0.02

// true means that taps will be normalized

fir_lowpass(taps, 960.0 / 48000.0, hann, true);

// show filter frequency response using dspplot python library

// dspplot must be installed before launching this example

plot_show("fir_lowpass_hann", taps, "title='15-point lowpass FIR, Hann window'");

}