TM_FFT_Functions

Library Functions. More...

Macros
#define	TM_FFT_GetMaxValue(FFT)    ((FFT)->MaxValue)
	Gets max value from already calculated FFT result. More...
#define	TM_FFT_GetMaxIndex(FFT)    ((FFT)->MaxIndex)
	Gets index value where max value happens from already calculated FFT result. More...
#define	TM_FFT_GetFFTSize(FFT)    ((FFT)->FFT_Size)
	Gets FFT size in units of samples length. More...
#define	TM_FFT_GetFromBuffer(FFT, index)    ((FFT)->Output[(uint16_t)(index)])
	Gets FFT result value from output buffer at given index. More...

Functions
uint8_t	TM_FFT_Init_F32 (TM_FFT_F32_t *FFT, uint16_t FFT_Size, uint8_t use_malloc)
	Initializes and prepares FFT structure for signal operations. More...
void	TM_FFT_SetBuffers_F32 (TM_FFT_F32_t *FFT, float32_t *InputBuffer, float32_t *OutputBuffer)
	Sets input and output buffers for FFT calculations. More...
uint8_t	TM_FFT_AddToBuffer (TM_FFT_F32_t *FFT, float32_t sampleValue)
	Adds new sample to input buffer in FFT array. More...
uint8_t	TM_FFT_AddToBufferWithImag (TM_FFT_F32_t *FFT, float32_t Real, float32_t Imag)
	Adds new sample (real and imaginary part if needed) to input buffer in FFT array. More...
void	TM_FFT_Process_F32 (TM_FFT_F32_t *FFT)
	Processes and calculates FFT from InputBuffer and saves data to Output buffer. More...
void	TM_FFT_Free_F32 (TM_FFT_F32_t *FFT)
	Free input and output buffers. More...

Detailed Description

Library Functions.

Macro Definition Documentation

#define TM_FFT_GetFFTSize

(

FFT

)

((FFT)->FFT_Size)

Gets FFT size in units of samples length.

Parameters

FFT	Pointer to TM_FFT_F32_t structure where FFT size will be checked

Return values

FFT	size in units of elements for calculation

Note

Defined as macro for faster execution

#define TM_FFT_GetFromBuffer	(		FFT,
			index
	)		((FFT)->Output[(uint16_t)(index)])

Gets FFT result value from output buffer at given index.

Parameters

FFT	Pointer to TM_FFT_F32_t structure where FFT output sample will be returned
index	Index in buffer where result will be returned. Valid input is between 0 and FFT_Size - 1

Return values

Value

at given index

Note

Defined as macro for faster execution

#define TM_FFT_GetMaxIndex

(

FFT

)

((FFT)->MaxIndex)

Gets index value where max value happens from already calculated FFT result.

Parameters

FFT	Pointer to TM_FFT_F32_t structure where max index at max value should be checked

Return values

None

Note

Defined as macro for faster execution

#define TM_FFT_GetMaxValue

(

FFT

)

((FFT)->MaxValue)

Gets max value from already calculated FFT result.

Parameters

FFT	Pointer to TM_FFT_F32_t structure where max value should be checked

Return values

None

Note

Defined as macro for faster execution

Function Documentation

uint8_t TM_FFT_AddToBuffer	(	TM_FFT_F32_t *	FFT,
		float32_t	sampleValue
	)

Adds new sample to input buffer in FFT array.

Parameters

*FFT	Pointer to TM_FFT_F32_t structure where new sample will be added
sampleValue	A new sample to be added to buffer, real part. Imaginary part will be set to 0

Return values

FFT	calculation status: 0: Input buffer is not full yet > 0: Input buffer is full and samples are ready to be calculated

uint8_t TM_FFT_AddToBufferWithImag	(	TM_FFT_F32_t *	FFT,
		float32_t	Real,
		float32_t	Imag
	)

Adds new sample (real and imaginary part if needed) to input buffer in FFT array.

Parameters

*FFT	Pointer to TM_FFT_F32_t structure where new sample will be added
Real	A new sample to be added to buffer, real part.
Imag	A new sample to be added to buffer, imaginary part.

Return values

FFT	calculation status: 0: Input buffer is not full yet > 0: Input buffer is full and samples are ready to be calculated

void TM_FFT_Free_F32

(

TM_FFT_F32_t *

FFT

)

Free input and output buffers.

Note

This function has sense only, if you used malloc for memory allocation when you called TM_FFT_Init_F32 function

Parameters

*FFT	Pointer to TM_FFT_F32_t structure where buffers will be free

Return values

None

uint8_t TM_FFT_Init_F32	(	TM_FFT_F32_t *	FFT,
		uint16_t	FFT_Size,
		uint8_t	use_malloc
	)

Initializes and prepares FFT structure for signal operations.

Parameters

*FFT	Pointer to empty TM_FFT_F32_t structure for FFT
FFT_Size	Number of samples to be used for FFT calculation This parameter can be a value of 2^n where n is between 4 and 12, so any power of 2 between 16 and 4096
use_malloc	Set parameter to 1, if you want to use HEAP memory and malloc to allocate input and output buffers

Note

It is recommended to use malloc for allocation, because FFT input and output buffers differs in length

Return values

Initialization

status: 0: Initialized OK, ready to use 1: Input FFT SIZE is not valid 2: Malloc failed with allocating input data buffer 3: Malloc failed with allocating output data buffer. If input data buffer is allocated, it will be free if this is returned.

void TM_FFT_Process_F32

(

TM_FFT_F32_t *

FFT

)

Processes and calculates FFT from InputBuffer and saves data to Output buffer.

Note

This function also calculates max value and max index in array where max value happens

Parameters

*FFT	Pointer to TM_FFT_F32_t where FFT calculation will happen

Return values

None

void TM_FFT_SetBuffers_F32	(	TM_FFT_F32_t *	FFT,
		float32_t *	InputBuffer,
		float32_t *	OutputBuffer
	)

Sets input and output buffers for FFT calculations.

Note

Use this function only if you set

• use_malloc parameter to zero in TM_FFT_Init_F32 function

Parameters

*FFT	Pointer to TM_FFT_F32_t structure where buffers will be set
*InputBuffer	Pointer to buffer of type float32_t with FFT_Size * 2 length
*OutputBuffer	Pointer to buffer of type float32_t with FFT_Size length

Return values

None