Data Structures
struct	msp_biquad_df1_q15_coeffs
	Coefficients for direct form 1 biquad filter. More...

struct	msp_biquad_df1_q15_states
	States for direct form 1 biquad filter. More...

struct	msp_biquad_df1_q15_params
	Parameter structure for direct form 1 biquad filter. More...

struct	msp_biquad_cascade_df1_q15_params
	Parameter structure for cascaded direct form 1 biquad filter. More...

struct	msp_biquad_df2_q15_coeffs
	Coefficients for direct form 2 biquad filter. When using LEA these coefficients must be placed into shared RAM. More...

struct	msp_biquad_df2_q15_states
	States for direct form 2 biquad filter. More...

struct	msp_biquad_df2_q15_params
	Parameter structure for direct form 2 biquad filter. More...

struct	msp_biquad_cascade_df2_q15_params
	Parameter structure for cascaded direct form 2 biquad filter. More...

struct	msp_biquad_df2_ext_q15_coeffs
	Coefficients for extended direct form 2 biquad filter. When using LEA these coefficients must be placed into shared RAM. More...

struct	msp_biquad_df2_ext_q15_states
	States for extended direct form 2 biquad filter. More...

struct	msp_biquad_df2_ext_q15_params
	Parameter structure for extended direct form 2 biquad filter. More...

struct	msp_biquad_cascade_df2_ext_q15_params
	Parameter structure for cascaded extended 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)
	Second-order direct form 1 biquad filter. More...

msp_status	msp_biquad_cascade_df1_q15 (const msp_biquad_cascade_df1_q15_params params, const _q15 src, _q15 *dst)
	Cascaded direct form 1 biquad filter. More...

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

msp_status	msp_biquad_cascade_df2_q15 (const msp_biquad_cascade_df2_q15_params params, const _q15 src, _q15 *dst)
	Cascaded direct form 2 biquad filter. More...

msp_status	msp_biquad_df2_ext_q15 (const msp_biquad_df2_ext_q15_params params, const _q15 src, _q15 *dst)
	Second-order direct form 2 biquad filter extended with DC bias and minimum and maximum tracking. More...

msp_status	msp_biquad_cascade_df2_ext_q15 (const msp_biquad_cascade_df2_ext_q15_params params, const _q15 src, _q15 *dst)
	Cascaded direct form 2 biquad filter extended with DC bias and minimum and maximum tracking. More...

Detailed Description

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

Function Documentation

msp_status msp_biquad_cascade_df1_q15	(	const msp_biquad_cascade_df1_q15_params *	params,
		const _q15 *	src,
		_q15 *	dst
	)

Cascaded direct form 1 biquad filter.

Details: Cascaded biquad filter with direct form 1 implementation. The coefficients are passed as an array of second-order sections (SOS matrix) and each section is passed to msp_biquad_df1_q15 to filter the input.

Example filter with three DF1 stages

LEA Support: This function is supported by LEA and requires data to be placed into shared LEA memory with 4-byte alignment.

Parameters

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

Returns: Status of the operation.

Examples:: filter_ex3_biquad_cascade_df1_q15.c.

msp_status msp_biquad_cascade_df2_ext_q15	(	const msp_biquad_cascade_df2_ext_q15_params *	params,
		const _q15 *	src,
		_q15 *	dst
	)

Cascaded direct form 2 biquad filter extended with DC bias and minimum and maximum tracking.

Details: Cascaded biquad filter with direct form 2 implementation extended to include bias and minimum and maximum state tracking. The coefficients are passed as an array of second-order sections (SOS matrix) and each section is passed to msp_biquad_df2_ext_q15 to filter the input.

Example filter with three DF2 stages

LEA Support: This function is supported by LEA and requires data to be placed into shared LEA memory with 4-byte alignment.

Parameters

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

Returns: Status of the operation.

Examples:: filter_ex5_biquad_cascade_df2_ext_q15.c.

msp_status msp_biquad_cascade_df2_q15	(	const msp_biquad_cascade_df2_q15_params *	params,
		const _q15 *	src,
		_q15 *	dst
	)

Cascaded direct form 2 biquad filter.

Details: Cascaded biquad filter with direct form 2 implementation. The coefficients are passed as an array of second-order sections (SOS matrix) and each section is passed to msp_biquad_df1_q15 to filter the input.

Example filter with three DF2 stages

LEA Support: This function is supported by LEA and requires data to be placed into shared LEA memory with 4-byte alignment.

Parameters

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

Returns: Status of the operation.

Examples:: filter_ex4_biquad_cascade_df2_q15.c.

msp_status msp_biquad_df1_q15	(	const msp_biquad_df1_q15_params *	params,
		const _q15 *	src,
		_q15 *	dst
	)

Second-order direct form 1 biquad filter.

Details: Second-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

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

LEA Support: This function is supported by LEA and requires data to be placed into shared LEA memory with 4-byte alignment.

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.

Returns: Status of the operation.

msp_status msp_biquad_df2_ext_q15	(	const msp_biquad_df2_ext_q15_params *	params,
		const _q15 *	src,
		_q15 *	dst
	)

Second-order direct form 2 biquad filter extended with DC bias and minimum and maximum tracking.

Details: Second-order direct form 2 biquad filter extended to include bias and minimum and maximum state tracking. 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 intermediate states are stored in the state structure.

Biquad DF2 structure (extended)

Pseudo code: y[n] = b0 * w[n] + b1 * w[n-1] + b2 * w[n-2]
w[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2]

LEA Support: This function is supported by LEA and requires data to be placed into shared LEA memory with 4-byte alignment.

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.

Returns: Status of the operation.

msp_status msp_biquad_df2_q15	(	const msp_biquad_df2_q15_params *	params,
		const _q15 *	src,
		_q15 *	dst
	)

Second-order direct form 2 biquad filter.

Details: Second-order direct form 2 biquad filter. Q15 multiplication is performed with a 32-bit accumulator to avoid intermediate overflow with saturation to Q15 when storing the result.

Biquad DF2 structure

Pseudo code: y[n] = b0 * w[n] + b1 * w[n-1] + b2 * w[n-2]
w[n] = a0 * x[n] + a1 * x[n-1] + a2 * x[n-2]

LEA Support: This function is supported by LEA and requires data to be placed into shared LEA memory with 4-byte alignment.

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.

Returns: Status of the operation.

Data Structures

Functions

Detailed Description

Function Documentation