FIRBlockOne

Filters vector of samples through FIR block filter.

Syntax

IppStatus ippsFIRBlockOne_32f(Ipp32f* pSrc, Ipp32f* pDst, IppsFIRBlockState_32f* pState, Ipp32f* pTaps);

Parameters

pSrc	Pointer to the input vector of samples to be filtered.
pDst	Pointer to the vector of filtered output samples.
pState	Pointer to the FIR filter state structure.
pTaps	Pointer to the vector of filter taps.

Description

This function is declared in the ippac.h header file. The function ippsFIRBlockOne filters a vector of samples pSrc of the length len through a filter and stores the result in pDst.

The filter taps are specified in the vector pTaps of the length order. The values of len and order parameters are specified in the ippsFIRBlockInitAlloc call.

In the following definition of the FIR filter, the sample of the input vector i to be filtered with the delay k is denoted xⁱ_n-k, and the taps are denoted h_k . The output value y_i is defined by the following formula:

Before calling the function ippsFIRBlockOne, initialize the filter state by calling the function ippsFIRBlockInitAlloc. Specify the taps values in the argument pTaps.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when at least one of the specified pointers is NULL.
ippStsContextMatchErr	Indicates an error when the state structure is invalid.
ippStsMisalignedBuf	Indicates misaligned arrays. Supply aligned data for better performance.
ippStsFIRLenErr	Indicates an error when one of the following conditions is true: pState->len is less than or equal to 0; pState->order is less than or equal to 0; pState->queue_end is less than 0; pState->queue_end is greater or equal to pState->order.

Single-Rate Filtering with the ippsFIRBlockOne Function

IppStatus fir(void)

#undef NUMITERS

#define NUMITERS 20

#undef BLOCKSIZE

#define BLOCKSIZE 20

	int n;

	int i;

	IppStatus status;

	IppsFIRBlockState_32f *fctx;

	Ipp32f x [BLOCKSIZE], y [BLOCKSIZE];

		const float taps[] = {

		0.0051f, 0.0180f, 0.0591f, 0.1245f, 0.1869f, 0.2127f, 0.1869f,

			0.1245f, 0.0591f, 0.0180f, 0.0051f, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

};

	ippsFIRBlockInitAlloc_32f( &fctx, 11, BLOCKSIZE );

	for (n =0;n<NUMITERS;++n)

		for (i = 0; i< BLOCKSIZE; i++) x[i]=(Ipp32f)sin(IPP_2PI *

			n *0.2 + i);

		status = ippsFIRBlockOne_32f( x, y, fctx, (Ipp32f*)taps );

		for (i = 0; i< BLOCKSIZE; i++)

			printf("%f", y[i]);

	ippsFIRBlockFree_32f(fctx);

	return status;