Data Structures
struct	msp_biquad_df1_q15_params
	Parameter structure for Direct Form 1 biquad filter. More...

struct	msp_biquad_df2_q15_params
	Parameter structure for Direct Form 2 biquad filter. More...

Functions
msp_status	msp_biquad_df1_q15 (const msp_biquad_df1_q15_params params, const _q15 src, _q15 *dst)
	Single order direct form 1 biquad filter. More...

msp_status	msp_biquad_df2_q15 (msp_biquad_df2_q15_params params, const _q15 src, _q15 *dst)
	Single order direct form 2 biquad filter. More...

Detailed Description

Functions for performing real Infinite Impulse Response (IIR) filters.

Function Documentation

Single order direct form 1 biquad filter.

Details: Single order biquad filter with direct form 1 implementation. Q15 multiplication is performed with a 32-bit accumulator to avoid intermediate overflow with saturation to Q15 when storing the result.

Biquad DF1 structure

Transfer Function: $H(z)=\frac{b_0+b_1z^{-1}+b_2z^{-2}}{a_0+a_1z^{-1}+a_2z^{-2}}$

Pseudo code: y[n] = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] - a1 * y[n-1] - a2 * y[n-2]

Parameters

params	Pointer to the biquad direct form 1 parameter structure.
src	Pointer to the source data to filter.
dst	Pointer to the destination vector.

Single order direct form 2 biquad filter.

Details: Single order direct form 2 biquad filter with bias and minimum and maximum result calculation. Q15 multiplication is performed with a 32-bit accumulator to avoid intermediate overflow with saturation to Q15 when storing the result. The maximum and minimum of the destination vector are returned for post processing.

Biquad DF2 structure

Transfer Function: $H(z)=\frac{b_0+b_1z^{-1}+b_2z^{-2}}{a_0+a_1z^{-1}+a_2z^{-1}+a_3z^{-2}}$

Pseudo code: y[n] = b0 * w[n] + b1 * w[n-1] + b2 * w[n-2]
w[n] = x[n] - a1 * x[n-1] - a2 * x[n-1] - a3 * x[n-2]

Parameters

params	Pointer to the biquad direct form 2 parameter structure.
src	Pointer to the source data to filter.
dst	Pointer to the destination vector.