Complex-by-Complex Multiplication

Functions
void	arm_cmplx_mult_cmplx_f16 (const float16_t *pSrcA, const float16_t *pSrcB, float16_t *pDst, uint32_t numSamples)
	Floating-point complex-by-complex multiplication.
void	arm_cmplx_mult_cmplx_f32 (const float32_t *pSrcA, const float32_t *pSrcB, float32_t *pDst, uint32_t numSamples)
	Floating-point complex-by-complex multiplication.
void	arm_cmplx_mult_cmplx_f64 (const float64_t *pSrcA, const float64_t *pSrcB, float64_t *pDst, uint32_t numSamples)
	Floating-point complex-by-complex multiplication.
void	arm_cmplx_mult_cmplx_q15 (const q15_t *pSrcA, const q15_t *pSrcB, q15_t *pDst, uint32_t numSamples)
	Q15 complex-by-complex multiplication.
void	arm_cmplx_mult_cmplx_q31 (const q31_t *pSrcA, const q31_t *pSrcB, q31_t *pDst, uint32_t numSamples)
	Q31 complex-by-complex multiplication.

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

arm_cmplx_mult_cmplx_f16()

void arm_cmplx_mult_cmplx_f16	(	const float16_t *	pSrcA,
		const float16_t *	pSrcB,
		float16_t *	pDst,
		uint32_t	numSamples
	)

Floating-point complex-by-complex multiplication.

Parameters

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

arm_cmplx_mult_cmplx_f32()

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

Floating-point complex-by-complex multiplication.

Parameters

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

arm_cmplx_mult_cmplx_f64()

void arm_cmplx_mult_cmplx_f64	(	const float64_t *	pSrcA,
		const float64_t *	pSrcB,
		float64_t *	pDst,
		uint32_t	numSamples
	)

Floating-point complex-by-complex multiplication.

Parameters

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

arm_cmplx_mult_cmplx_q15()

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

Q15 complex-by-complex multiplication.

Parameters

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

Scaling and Overflow Behavior

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

arm_cmplx_mult_cmplx_q31()

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

Q31 complex-by-complex multiplication.

Parameters

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

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.