CMSIS-DSP: Complex-by-Real Multiplication

| CMSIS-DSP Version 1.4.7 CMSIS DSP Software Library

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Complex-by-Real Multiplication
Complex Math Functions

## Functions

void | arm_cmplx_mult_real_f32 (float32_t *pSrcCmplx, float32_t *pSrcReal, float32_t *pCmplxDst, uint32_t numSamples)
| Floating-point complex-by-real multiplication.
void | arm_cmplx_mult_real_q15 (q15_t *pSrcCmplx, q15_t *pSrcReal, q15_t *pCmplxDst, uint32_t numSamples)
| Q15 complex-by-real multiplication.
void | arm_cmplx_mult_real_q31 (q31_t *pSrcCmplx, q31_t *pSrcReal, q31_t *pCmplxDst, uint32_t numSamples)
| Q31 complex-by-real multiplication.

## Description

Multiplies a complex vector by a real 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 while the real array has a total of `numSamples` real values.

The underlying algorithm is used:

    for(n=0; n<numSamples; n++) {
        pCmplxDst[(2*n)+0] = pSrcCmplx[(2*n)+0] * pSrcReal[n];
        pCmplxDst[(2*n)+1] = pSrcCmplx[(2*n)+1] * pSrcReal[n];
    }

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

## Function Documentation

void arm_cmplx_mult_real_f32 | ( | float32_t * | pSrcCmplx,
|  | float32_t * | pSrcReal,
|  | float32_t * | pCmplxDst,
|  | uint32_t | numSamples
| ) |  |

Parameters

  [in] | *pSrcCmplx | points to the complex input vector
  [in] | *pSrcReal | points to the real input vector
  [out] | *pCmplxDst | points to the complex output vector
  [in] | numSamples | number of samples in each vector

Returns
  none.

void arm_cmplx_mult_real_q15 | ( | q15_t * | pSrcCmplx,
|  | q15_t * | pSrcReal,
|  | q15_t * | pCmplxDst,
|  | uint32_t | numSamples
| ) |  |

Parameters

  [in] | *pSrcCmplx | points to the complex input vector
  [in] | *pSrcReal | points to the real input vector
  [out] | *pCmplxDst | points to the complex output vector
  [in] | numSamples | number of samples in each vector

Returns
  none.

Scaling and Overflow Behavior:

  The function uses saturating arithmetic. Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated.

References __SIMD32.

void arm_cmplx_mult_real_q31 | ( | q31_t * | pSrcCmplx,
|  | q31_t * | pSrcReal,
|  | q31_t * | pCmplxDst,
|  | uint32_t | numSamples
| ) |  |

Parameters

  [in] | *pSrcCmplx | points to the complex input vector
  [in] | *pSrcReal | points to the real input vector
  [out] | *pCmplxDst | points to the complex output vector
  [in] | numSamples | number of samples in each vector

Returns
  none.

Scaling and Overflow Behavior:

  The function uses saturating arithmetic. Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.

References clip_q63_to_q31().