 CMSIS-DSP  Version 1.9.0 CMSIS DSP Software Library
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. More...

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. More...

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. More...

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. 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_f16 ( const float16_t * pSrcA, const float16_t * pSrcB, float16_t * pDst, uint32_t numSamples )
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
Returns
none
 void arm_cmplx_mult_cmplx_f32 ( const float32_t * pSrcA, const float32_t * pSrcB, float32_t * pDst, uint32_t numSamples )
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
Returns
none
 void arm_cmplx_mult_cmplx_q15 ( const q15_t * pSrcA, const q15_t * pSrcB, q15_t * pDst, uint32_t numSamples )
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
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 ( const q31_t * pSrcA, const q31_t * pSrcB, q31_t * pDst, uint32_t numSamples )
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
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.