filtertype | = | Chebyshev |
passtype | = | Lowpass |
ripple | = | -0.07 |
order | = | 4 |
samplerate | = | 28000 |
corner1 | = | 12500 |
corner2 | = | |
adzero | = | |
logmin | = |
Command line: /www/usr/fisher/helpers/mkfilter -Ch -7.0000000000e-02 -Lp -o 4 -a 4.4642857143e-01 0.0000000000e+00 raw alpha1 = 0.4464285714 raw alpha2 = 0.4464285714 warped alpha1 = 1.8734378073 warped alpha2 = 1.8734378073 gain at dc : mag = 1.497238168e+00 phase = 0.0000000000 pi gain at centre: mag = 1.497238168e+00 phase = -0.8699514648 pi gain at hf : mag = 0.000000000e+00 S-plane zeros: S-plane poles: -3.3566304357 + j 13.5623439769 -8.1036227218 + j 5.6177068128 -8.1036227218 + j -5.6177068128 -3.3566304357 + j -13.5623439769 Z-plane zeros: -1.0000000000 + j 0.0000000000 4 times Z-plane poles: -0.8992312710 + j 0.2551343016 -0.6975909913 + j 0.1681421798 -0.6975909913 + j -0.1681421798 -0.8992312710 + j -0.2551343016 Recurrence relation: y[n] = ( 1 * x[n- 4]) + ( 4 * x[n- 3]) + ( 6 * x[n- 2]) + ( 4 * x[n- 1]) + ( 1 * x[n- 0]) + ( -0.4498778345 * y[n- 4]) + ( -2.1450223211 * y[n- 3]) + ( -3.8977979094 * y[n- 2]) + ( -3.1936445246 * y[n- 1])
/* Digital filter designed by mkfilter/mkshape/gencode A.J. Fisher Command line: /www/usr/fisher/helpers/mkfilter -Ch -7.0000000000e-02 -Lp -o 4 -a 4.4642857143e-01 0.0000000000e+00 -l */ #define NZEROS 4 #define NPOLES 4 #define GAIN 1.497238168e+00 static float xv[NZEROS+1], yv[NPOLES+1]; static void filterloop() { for (;;) { xv[0] = xv[1]; xv[1] = xv[2]; xv[2] = xv[3]; xv[3] = xv[4]; xv[4] = next input value / GAIN; yv[0] = yv[1]; yv[1] = yv[2]; yv[2] = yv[3]; yv[3] = yv[4]; yv[4] = (xv[0] + xv[4]) + 4 * (xv[1] + xv[3]) + 6 * xv[2] + ( -0.4498778345 * yv[0]) + ( -2.1450223211 * yv[1]) + ( -3.8977979094 * yv[2]) + ( -3.1936445246 * yv[3]); next output value = yv[4]; } }
For an expanded view, enter frequency limits (as a fraction of the sampling rate) here:
For a view on a different scale, enter upper time limit (integer number of samples) here: