Tom's MMT Pages

May 25, 2020

MMT servos - KSS - Output "20 Hz" notch

This is labeled notch20b in the model. This is the second of 4 filters that process servo output The routine that sets up these filters looks like this:

void
flexmode_init ( void )
{
        flex_n567 = n567_init ();
        flex_n20 = n20_init ();
        flex_n35 = n35_init ();
        flex_ho = ho_init ();
}

The 20 Hz notch filter is set up as follows:

/* Tested OK 8-12-2010 */
/* matches orignal to 1.0e-16 */
/* same old and new */
/* 20 Hz notch (attenuates from 16-24 Hz) */
struct ss2_info *
n20_init ( void )
{
        static double a_data[3] = { 1.9361813359339619E+00, -9.5095678150106799E-01, 1.0 };
        static double b_data = 0.25;
        static double c_data[2] = { -1.8991312862352672E-01, 1.9136239943426014E-01 };
        static double d_data = 9.7547839075053400E-01;

        return ss2_init ( a_data, b_data, c_data, d_data );
}