Complex-by-Complex Multiplication

Functions
void	arm_cmplx_mult_cmplx_f32 (float32_t *pSrcA, float32_t *pSrcB, float32_t *pDst, uint32_t numSamples)
	Floating-point complex-by-complex multiplication. More...
void	arm_cmplx_mult_cmplx_q15 (q15_t *pSrcA, q15_t *pSrcB, q15_t *pDst, uint32_t numSamples)
	Q15 complex-by-complex multiplication. More...
void	arm_cmplx_mult_cmplx_q31 (q31_t *pSrcA, q31_t *pSrcB, q31_t *pDst, uint32_t numSamples)
	Q31 complex-by-complex multiplication. More...

Description

Multiplies a complex vector by another complex vector and generates a complex result. The data in the complex arrays is stored in an interleaved fashion (real, imag, real, imag, ...). The parameter numSamples represents the number of complex samples processed. The complex arrays have a total of 2*numSamples real values.

The underlying algorithm is used:

for(n=0; n<numSamples; n++) {
    pDst[(2*n)+0] = pSrcA[(2*n)+0] * pSrcB[(2*n)+0] - pSrcA[(2*n)+1] * pSrcB[(2*n)+1];
    pDst[(2*n)+1] = pSrcA[(2*n)+0] * pSrcB[(2*n)+1] + pSrcA[(2*n)+1] * pSrcB[(2*n)+0];
}

There are separate functions for floating-point, Q15, and Q31 data types.

Function Documentation

void arm_cmplx_mult_cmplx_f32	(	float32_t *	pSrcA,
		float32_t *	pSrcB,
		float32_t *	pDst,
		uint32_t	numSamples
	)

Parameters

[in]	*pSrcA	points to the first input vector
[in]	*pSrcB	points to the second input vector
[out]	*pDst	points to the output vector
[in]	numSamples	number of complex samples in each vector

Returns

none.

Referenced by main().

void arm_cmplx_mult_cmplx_q15	(	q15_t *	pSrcA,
		q15_t *	pSrcB,
		q15_t *	pDst,
		uint32_t	numSamples
	)

Parameters

[in]	*pSrcA	points to the first input vector
[in]	*pSrcB	points to the second input vector
[out]	*pDst	points to the output vector
[in]	numSamples	number of complex samples in each vector

Returns

none.

Scaling and Overflow Behavior:

The function implements 1.15 by 1.15 multiplications and finally output is converted into 3.13 format.

void arm_cmplx_mult_cmplx_q31	(	q31_t *	pSrcA,
		q31_t *	pSrcB,
		q31_t *	pDst,
		uint32_t	numSamples
	)

Parameters

[in]	*pSrcA	points to the first input vector
[in]	*pSrcB	points to the second input vector
[out]	*pDst	points to the output vector
[in]	numSamples	number of complex samples in each vector

Returns

none.

Scaling and Overflow Behavior:

The function implements 1.31 by 1.31 multiplications and finally output is converted into 3.29 format. Input down scaling is not required.

Referenced by arm_dct4_q31().