Complex-by-Complex Multiplication [Complex Math Functions]

Functions
void	arm_cmplx_mult_cmplx_f32 (float32_t *pSrcA, float32_t *pSrcB, float32_t *pDst, uint32_t numSamples)
void	arm_cmplx_mult_cmplx_q31 (q31_t *pSrcA, q31_t *pSrcB, q31_t *pDst, uint32_t numSamples)
void	arm_cmplx_mult_cmplx_q15 (q15_t *pSrcA, q15_t *pSrcB, q15_t *pDst, uint32_t numSamples)

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Detailed 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.

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Function Documentation

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

Floating-point complex-by-complex multiplication.

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.

Examples:

arm_convolution_example_f32.c.

Definition at line 67 of file arm_cmplx_mult_cmplx_f32.c.

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

Q31 complex-by-complex multiplication.

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.

Definition at line 50 of file arm_cmplx_mult_cmplx_q31.c.

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

Q15 complex-by-complex multiplication.

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.

Conditions for optimum performance

Input and output buffers should be aligned by 32-bit

Scaling and Overflow Behavior:

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

Definition at line 52 of file arm_cmplx_mult_cmplx_q15.c.