for (int i = 0; i < n; i++, z += zinc)
q[i] = frequencyResponse (filterID, bw, z, param) * cos (TWOPI * z * x);
double y = 2 * integrateSimpson (zmin, zmax, q, n);
for (int i = 0; i < n; i++, z += zinc)
q[i] = frequencyResponse (filterID, bw, z, param) * cos (TWOPI * z * x);
double y = 2 * integrateSimpson (zmin, zmax, q, n);