Eli Hughes / CMSIS_DSP_401

V4.0.1 of the ARM CMSIS DSP libraries. Note that arm_bitreversal2.s, arm_cfft_f32.c and arm_rfft_fast_f32.c had to be removed. arm_bitreversal2.s will not assemble with the online tools. So, the fast f32 FFT functions are not yet available. All the other FFT functions are available.

Dependents:   MPU9150_Example fir_f32 fir_f32 MPU9150_nucleo_noni2cdev ... more

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Vector Inverse Clarke Transform
Functions

Vector Inverse Clarke Transform
[Controller Functions]

Inverse Clarke transform converts the two-coordinate time invariant vector into instantaneous stator phases. More...

Functions

static __INLINE void arm_inv_clarke_f32 (float32_t Ialpha, float32_t Ibeta, float32_t *pIa, float32_t *pIb)
 Floating-point Inverse Clarke transform.
static __INLINE void arm_inv_clarke_q31 (q31_t Ialpha, q31_t Ibeta, q31_t *pIa, q31_t *pIb)
 Inverse Clarke transform for Q31 version.

Detailed Description

Inverse Clarke transform converts the two-coordinate time invariant vector into instantaneous stator phases.

The function operates on a single sample of data and each call to the function returns the processed output. The library provides separate functions for Q31 and floating-point data types.

Algorithm
clarkeInvFormula.gif
where pIa and pIb are the instantaneous stator phases and Ialpha and Ibeta are the two coordinates of time invariant vector.
Fixed-Point Behavior
Care must be taken when using the Q31 version of the Clarke transform. In particular, the overflow and saturation behavior of the accumulator used must be considered. Refer to the function specific documentation below for usage guidelines.

Function Documentation

static __INLINE void arm_inv_clarke_f32 ( float32_t  Ialpha,
float32_t  Ibeta,
float32_t *  pIa,
float32_t *  pIb 
) [static]

Floating-point Inverse Clarke transform.

Parameters:
[in]Ialphainput two-phase orthogonal vector axis alpha
[in]Ibetainput two-phase orthogonal vector axis beta
[out]*pIapoints to output three-phase coordinate a
[out]*pIbpoints to output three-phase coordinate b
Returns:
none.

Definition at line 5240 of file arm_math.h.

static __INLINE void arm_inv_clarke_q31 ( q31_t  Ialpha,
q31_t  Ibeta,
q31_t *  pIa,
q31_t *  pIb 
) [static]

Inverse Clarke transform for Q31 version.

Parameters:
[in]Ialphainput two-phase orthogonal vector axis alpha
[in]Ibetainput two-phase orthogonal vector axis beta
[out]*pIapoints to output three-phase coordinate a
[out]*pIbpoints to output three-phase coordinate b
Returns:
none.

Scaling and Overflow Behavior:

The function is implemented using an internal 32-bit accumulator. The accumulator maintains 1.31 format by truncating lower 31 bits of the intermediate multiplication in 2.62 format. There is saturation on the subtraction, hence there is no risk of overflow.

Definition at line 5269 of file arm_math.h.

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