iir

C++ interface for Infinite Impulse Response. More...

array	iir (int nb, const float *h_b, int na, const float *h_a, const array &x)
array	iir (const array &b, const array &a, const array &x)

Detailed Description

C++ interface for Infinite Impulse Response.

Apply an infinite impulse response filter (transposed Direct Form II implementation).

If a is scalar this defaults to the faster Finite Impulse Response, i.e. fir. The IIR is defined as:

\[ a_0*y_{n-1} = b_0*x_{n-1} + b_1*x_{n-2} + \ldots + b_{nb-1}*x_{n-nb-1} - a_1*y_{n-2} - \ldots - a_{na-1}*y_{n-na-1} \]

array a = seq(1, 8);
a = a / 10.0f;
print(a);
// a = 0.1000
//     0.2000
//     0.3000
//     0.4000
//     0.5000
//     0.6000
//     0.7000
//     0.8000

array b = seq(1, 8);
print(b);
// b = 1.0000
//     2.0000
//     3.0000
//     4.0000
//     5.0000
//     6.0000
//     7.0000
//     8.0000

array x = randn(8, 1);
array f = iir(b, a, x);
print(f);
// f =  2.9254
//     -7.1836
//      1.0000
//     -3.9320
//     25.4702
//     -0.0344
//      0.0829
//     -2.5098

Function Documentation

array af::iir	(	int	nb,
		const float *	h_b,
		int	na,
		const float *	h_a,
		const array &	x
	)

Parameters

[in]	nb	length of h_b
[in]	h_b	host-vector feedforward filter coefficients
[in]	na	length of h_a
[in]	h_a	host-vector feedback filter coefficients
[in]	x

Returns

filtered signal (y) same size as x

array af::iir	(	const array &	b,
		const array &	a,
		const array &	x
	)

Parameters

[in]	b	feedforward filter coefficients
[in]	a	feedback filter coefficients
[in]	x

Returns

filtered signal (y) same size as x