filter1D

C interface for Impulse Response. More...

afError	af_filter1D_S (float *d_out, unsigned len_in, const float *d_in, unsigned len_a, const float *h_a, unsigned len_b, const float *h_b, const float *d_init, float *d_final, unsigned Nin, unsigned Ninit)
afError	af_filter1D_C (cfloat *d_out, unsigned len_in, const cfloat *d_in, unsigned len_a, const float *h_a, unsigned len_b, const float *h_b, const cfloat *d_init, cfloat *d_final, unsigned Nin, unsigned Ninit)
	Complex, single-precision, Transposed direct form II filtering. More...
afError	af_filter1D_D (double *d_out, unsigned len_in, const double *d_in, unsigned len_a, const double *h_a, unsigned len_b, const double *h_b, const double *d_init, double *d_final, unsigned Nin, unsigned Ninit)
	Double-precision, Transposed direct form II filtering. More...
afError	af_filter1D_Z (cdouble *d_out, unsigned len_in, const cdouble *d_in, unsigned len_a, const double *h_a, unsigned len_b, const double *h_b, const cdouble *d_init, cdouble *d_final, unsigned Nin, unsigned Ninit)
	Complex, single-precision, Transposed direct form II filtering. More...

Detailed Description

C interface for 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

afError af_filter1D_S	(	float *	d_out,
		unsigned	len_in,
		const float *	d_in,
		unsigned	len_a,
		const float *	h_a,
		unsigned	len_b,
		const float *	h_b,
		const float *	d_init,
		float *	d_final,
		unsigned	Nin,
		unsigned	Ninit
	)

Parameters

[out]	d_out	The filtered output
[in]	len_in	Size of input array
[in]	d_in	Input to the filter
[in]	len_a	Number of feed-forward co-efficients (maximum 50)
[in]	h_a	Feed-forward co-efficients
[in]	len_b	Number of feed-forward co-efficients (maximum 50)
[in]	h_b	Feed-back co-efficients
[in]	d_init	Initial value of the delay units
[out]	d_final	Final value of the delay units
[in]	Nin	Number of input batches
[in]	Ninit	Number of initial conditionsSingle-precision, Transposed direct form II filtering

afError af_filter1D_C	(	cfloat *	d_out,
		unsigned	len_in,
		const cfloat *	d_in,
		unsigned	len_a,
		const float *	h_a,
		unsigned	len_b,
		const float *	h_b,
		const cfloat *	d_init,
		cfloat *	d_final,
		unsigned	Nin,
		unsigned	Ninit
	)

Complex, single-precision, Transposed direct form II filtering.

afError af_filter1D_D	(	double *	d_out,
		unsigned	len_in,
		const double *	d_in,
		unsigned	len_a,
		const double *	h_a,
		unsigned	len_b,
		const double *	h_b,
		const double *	d_init,
		double *	d_final,
		unsigned	Nin,
		unsigned	Ninit
	)

Double-precision, Transposed direct form II filtering.

afError af_filter1D_Z	(	cdouble *	d_out,
		unsigned	len_in,
		const cdouble *	d_in,
		unsigned	len_a,
		const double *	h_a,
		unsigned	len_b,
		const double *	h_b,
		const cdouble *	d_init,
		cdouble *	d_final,
		unsigned	Nin,
		unsigned	Ninit
	)

Complex, single-precision, Transposed direct form II filtering.