From 96d6da4e252b06dcfdc041e7df23e86161c33007 Mon Sep 17 00:00:00 2001 From: rihab kouki Date: Tue, 28 Jul 2020 11:24:49 +0100 Subject: Official ARM version: v5.6.0 --- docs/DSP/html/group__ComplexFFT.html | 320 ++++++++++++++++++++--------------- 1 file changed, 184 insertions(+), 136 deletions(-) (limited to 'docs/DSP/html/group__ComplexFFT.html') diff --git a/docs/DSP/html/group__ComplexFFT.html b/docs/DSP/html/group__ComplexFFT.html index 6cd2383..e0e7191 100644 --- a/docs/DSP/html/group__ComplexFFT.html +++ b/docs/DSP/html/group__ComplexFFT.html @@ -32,7 +32,7 @@ Logo
CMSIS-DSP -  Version 1.5.2 +  Version 1.7.0
CMSIS DSP Software Library
@@ -126,10 +126,10 @@ Functions  Processing function for the floating-point complex FFT. More...
  void arm_cfft_q15 (const arm_cfft_instance_q15 *S, q15_t *p1, uint8_t ifftFlag, uint8_t bitReverseFlag) - Processing function for the Q15 complex FFT. More...
+ Processing function for Q15 complex FFT. More...
  void arm_cfft_q31 (const arm_cfft_instance_q31 *S, q31_t *p1, uint8_t ifftFlag, uint8_t bitReverseFlag) - Processing function for the fixed-point complex FFT in Q31 format. More...
+ Processing function for the Q31 complex FFT. More...
  void arm_cfft_radix2_f32 (const arm_cfft_radix2_instance_f32 *S, float32_t *pSrc)  Radix-2 CFFT/CIFFT. More...
@@ -171,7 +171,7 @@ Functions

Description

The Fast Fourier Transform (FFT) is an efficient algorithm for computing the Discrete Fourier Transform (DFT). The FFT can be orders of magnitude faster than the DFT, especially for long lengths. The algorithms described in this section operate on complex data. A separate set of functions is devoted to handling of real sequences.
There are separate algorithms for handling floating-point, Q15, and Q31 data types. The algorithms available for each data type are described next.
-
The FFT functions operate in-place. That is, the array holding the input data will also be used to hold the corresponding result. The input data is complex and contains 2*fftLen interleaved values as shown below. 
 {real[0], imag[0], real[1], imag[1],..}
The FFT result will be contained in the same array and the frequency domain values will have the same interleaving.
+
The FFT functions operate in-place. That is, the array holding the input data will also be used to hold the corresponding result. The input data is complex and contains 2*fftLen interleaved values as shown below. 
{real[0], imag[0], real[1], imag[1], ...}
The FFT result will be contained in the same array and the frequency domain values will have the same interleaving.
Floating-point
The floating-point complex FFT uses a mixed-radix algorithm. Multiple radix-8 stages are performed along with a single radix-2 or radix-4 stage, as needed. The algorithm supports lengths of [16, 32, 64, ..., 4096] and each length uses a different twiddle factor table.
The function uses the standard FFT definition and output values may grow by a factor of fftLen when computing the forward transform. The inverse transform includes a scale of 1/fftLen as part of the calculation and this matches the textbook definition of the inverse FFT.
Pre-initialized data structures containing twiddle factors and bit reversal tables are provided and defined in arm_const_structs.h. Include this header in your function and then pass one of the constant structures as an argument to arm_cfft_f32. For example:
@@ -286,18 +286,22 @@ Functions
Parameters
- - - - + + + +
[in]*Spoints to an instance of the floating-point CFFT structure.
[in,out]*p1points to the complex data buffer of size 2*fftLen. Processing occurs in-place.
[in]ifftFlagflag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
[in]bitReverseFlagflag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
[in]Spoints to an instance of the floating-point CFFT structure
[in,out]p1points to the complex data buffer of size 2*fftLen. Processing occurs in-place
[in]ifftFlagflag that selects transform direction
    +
  • value = 0: forward transform
    • +
  • value = 1: inverse transform
    • +
+
[in]bitReverseFlagflag that enables / disables bit reversal of output
    +
  • value = 0: disables bit reversal of output
    • +
  • value = 1: enables bit reversal of output
    • +
+
-
Returns
none.
- -

References arm_bitreversal_32(), arm_cfft_radix8by2_f32(), arm_cfft_radix8by4_f32(), arm_radix8_butterfly_f32(), arm_cfft_instance_f32::bitRevLength, arm_cfft_instance_f32::fftLen, arm_cfft_instance_f32::pBitRevTable, and arm_cfft_instance_f32::pTwiddle.

- -

Referenced by arm_rfft_fast_f32(), and main().

+
Returns
none
@@ -338,18 +342,22 @@ Functions
Parameters
- - - - + + + +
[in]*Spoints to an instance of the Q15 CFFT structure.
[in,out]*p1points to the complex data buffer of size 2*fftLen. Processing occurs in-place.
[in]ifftFlagflag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
[in]bitReverseFlagflag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
[in]Spoints to an instance of Q15 CFFT structure
[in,out]p1points to the complex data buffer of size 2*fftLen. Processing occurs in-place
[in]ifftFlagflag that selects transform direction
    +
  • value = 0: forward transform
    • +
  • value = 1: inverse transform
    • +
+
[in]bitReverseFlagflag that enables / disables bit reversal of output
    +
  • value = 0: disables bit reversal of output
    • +
  • value = 1: enables bit reversal of output
    • +
+
-
Returns
none.
- -

References arm_bitreversal_16(), arm_cfft_radix4by2_inverse_q15(), arm_cfft_radix4by2_q15(), arm_radix4_butterfly_inverse_q15(), arm_radix4_butterfly_q15(), arm_cfft_instance_q15::bitRevLength, arm_cfft_instance_q15::fftLen, arm_cfft_instance_q15::pBitRevTable, and arm_cfft_instance_q15::pTwiddle.

- -

Referenced by arm_rfft_q15().

+
Returns
none
@@ -390,18 +398,22 @@ Functions
Parameters
- - - - + + + +
[in]*Spoints to an instance of the fixed-point CFFT structure.
[in,out]*p1points to the complex data buffer of size 2*fftLen. Processing occurs in-place.
[in]ifftFlagflag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
[in]bitReverseFlagflag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
[in]Spoints to an instance of the fixed-point CFFT structure
[in,out]p1points to the complex data buffer of size 2*fftLen. Processing occurs in-place
[in]ifftFlagflag that selects transform direction
    +
  • value = 0: forward transform
    • +
  • value = 1: inverse transform
    • +
+
[in]bitReverseFlagflag that enables / disables bit reversal of output
    +
  • value = 0: disables bit reversal of output
    • +
  • value = 1: enables bit reversal of output
    • +
+
-
Returns
none.
- -

References arm_bitreversal_32(), arm_cfft_radix4by2_inverse_q31(), arm_cfft_radix4by2_q31(), arm_radix4_butterfly_inverse_q31(), arm_radix4_butterfly_q31(), arm_cfft_instance_q31::bitRevLength, arm_cfft_instance_q31::fftLen, arm_cfft_instance_q31::pBitRevTable, and arm_cfft_instance_q31::pTwiddle.

- -

Referenced by arm_rfft_q31().

+
Returns
none
@@ -428,18 +440,16 @@ Functions
-
Deprecated:
Do not use this function. It has been superseded by arm_cfft_f32 and will be removed in the future.
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_f32 and will be removed in the future
Parameters
- - + +
[in]*Spoints to an instance of the floating-point Radix-2 CFFT/CIFFT structure.
[in,out]*pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place.
[in]Spoints to an instance of the floating-point Radix-2 CFFT/CIFFT structure
[in,out]pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place
-
Returns
none.
+
Returns
none
-

References arm_bitreversal_f32(), arm_radix2_butterfly_f32(), arm_radix2_butterfly_inverse_f32(), arm_cfft_radix2_instance_f32::bitReverseFlag, arm_cfft_radix2_instance_f32::bitRevFactor, arm_cfft_radix2_instance_f32::fftLen, arm_cfft_radix2_instance_f32::ifftFlag, arm_cfft_radix2_instance_f32::onebyfftLen, arm_cfft_radix2_instance_f32::pBitRevTable, arm_cfft_radix2_instance_f32::pTwiddle, and arm_cfft_radix2_instance_f32::twidCoefModifier.

-
@@ -477,25 +487,34 @@ Functions
-
Deprecated:
Do not use this function. It has been superseded by arm_cfft_f32 and will be removed in the future.
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_f32 and will be removed in the future.
Parameters
- - - - + + + +
[in,out]*Spoints to an instance of the floating-point CFFT/CIFFT structure.
[in]fftLenlength of the FFT.
[in]ifftFlagflag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
[in]bitReverseFlagflag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
[in,out]Spoints to an instance of the floating-point CFFT/CIFFT structure
[in]fftLenlength of the FFT
[in]ifftFlagflag that selects transform direction
    +
  • value = 0: forward transform
    • +
  • value = 1: inverse transform
    • +
+
[in]bitReverseFlagflag that enables / disables bit reversal of output
    +
  • value = 0: disables bit reversal of output
    • +
  • value = 1: enables bit reversal of output
    • +
+
-
Returns
The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if fftLen is not a supported value.
+
Returns
execution status
-
Description:
-
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
+
+
Details
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
The parameter bitReverseFlag controls whether output is in normal order or bit reversed order. Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
The parameter fftLen Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
-

References ARM_MATH_ARGUMENT_ERROR, ARM_MATH_SUCCESS, armBitRevTable, arm_cfft_radix2_instance_f32::bitReverseFlag, arm_cfft_radix2_instance_f32::bitRevFactor, arm_cfft_radix2_instance_f32::fftLen, ifftFlag, arm_cfft_radix2_instance_f32::ifftFlag, arm_cfft_radix2_instance_f32::onebyfftLen, arm_cfft_radix2_instance_f32::pBitRevTable, arm_cfft_radix2_instance_f32::pTwiddle, status, arm_cfft_radix2_instance_f32::twidCoefModifier, and twiddleCoef.

-
@@ -533,25 +552,34 @@ Functions
-
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q15 and will be removed
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q15 and will be removed
Parameters
- + - - + +
[in,out]*Spoints to an instance of the Q15 CFFT/CIFFT structure.
[in,out]Spoints to an instance of the Q15 CFFT/CIFFT structure.
[in]fftLenlength of the FFT.
[in]ifftFlagflag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
[in]bitReverseFlagflag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
[in]ifftFlagflag that selects transform direction
    +
  • value = 0: forward transform
    • +
  • value = 1: inverse transform
    • +
+
[in]bitReverseFlagflag that enables / disables bit reversal of output
    +
  • value = 0: disables bit reversal of output
    • +
  • value = 1: enables bit reversal of output
    • +
+
-
Returns
The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if fftLen is not a supported value.
+
Returns
execution status
-
Description:
-
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
+
+
Details
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
The parameter bitReverseFlag controls whether output is in normal order or bit reversed order. Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
The parameter fftLen Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
-

References ARM_MATH_ARGUMENT_ERROR, ARM_MATH_SUCCESS, armBitRevTable, arm_cfft_radix2_instance_q15::bitReverseFlag, arm_cfft_radix2_instance_q15::bitRevFactor, arm_cfft_radix2_instance_q15::fftLen, ifftFlag, arm_cfft_radix2_instance_q15::ifftFlag, arm_cfft_radix2_instance_q15::pBitRevTable, arm_cfft_radix2_instance_q15::pTwiddle, status, arm_cfft_radix2_instance_q15::twidCoefModifier, and twiddleCoef_4096_q15.

-
@@ -589,25 +617,34 @@ Functions
-
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q31 and will be removed
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q31 and will be removed in the future.
Parameters
- - - - + + + +
[in,out]*Spoints to an instance of the Q31 CFFT/CIFFT structure.
[in]fftLenlength of the FFT.
[in]ifftFlagflag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
[in]bitReverseFlagflag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
[in,out]Spoints to an instance of the Q31 CFFT/CIFFT structure
[in]fftLenlength of the FFT
[in]ifftFlagflag that selects transform direction
    +
  • value = 0: forward transform
    • +
  • value = 1: inverse transform
    • +
+
[in]bitReverseFlagflag that enables / disables bit reversal of output
    +
  • value = 0: disables bit reversal of output
    • +
  • value = 1: enables bit reversal of output
    • +
+
-
Returns
The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if fftLen is not a supported value.
+
Returns
execution status +
-
Description:
-
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
+
Details
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
The parameter bitReverseFlag controls whether output is in normal order or bit reversed order. Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
The parameter fftLen Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
-

References ARM_MATH_ARGUMENT_ERROR, ARM_MATH_SUCCESS, armBitRevTable, arm_cfft_radix2_instance_q31::bitReverseFlag, arm_cfft_radix2_instance_q31::bitRevFactor, arm_cfft_radix2_instance_q31::fftLen, ifftFlag, arm_cfft_radix2_instance_q31::ifftFlag, arm_cfft_radix2_instance_q31::pBitRevTable, arm_cfft_radix2_instance_q31::pTwiddle, status, arm_cfft_radix2_instance_q31::twidCoefModifier, and twiddleCoef_4096_q31.

-
@@ -633,18 +670,16 @@ Functions
-
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q15 and will be removed
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q15 and will be removed in the future.
Parameters
- - + +
[in]*Spoints to an instance of the fixed-point CFFT/CIFFT structure.
[in,out]*pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place.
[in]Spoints to an instance of the fixed-point CFFT/CIFFT structure
[in,out]pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place
-
Returns
none.
+
Returns
none
-

References arm_bitreversal_q15(), arm_radix2_butterfly_inverse_q15(), arm_radix2_butterfly_q15(), arm_cfft_radix2_instance_q15::bitRevFactor, arm_cfft_radix2_instance_q15::fftLen, arm_cfft_radix2_instance_q15::ifftFlag, arm_cfft_radix2_instance_q15::pBitRevTable, arm_cfft_radix2_instance_q15::pTwiddle, and arm_cfft_radix2_instance_q15::twidCoefModifier.

-
@@ -670,18 +705,16 @@ Functions
-
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q31 and will be removed
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q31 and will be removed in the future.
Parameters
- - + +
[in]*Spoints to an instance of the fixed-point CFFT/CIFFT structure.
[in,out]*pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place.
[in]Spoints to an instance of the fixed-point CFFT/CIFFT structure
[in,out]pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place
-
Returns
none.
+
Returns
none
-

References arm_bitreversal_q31(), arm_radix2_butterfly_inverse_q31(), arm_radix2_butterfly_q31(), arm_cfft_radix2_instance_q31::bitRevFactor, arm_cfft_radix2_instance_q31::fftLen, arm_cfft_radix2_instance_q31::ifftFlag, arm_cfft_radix2_instance_q31::pBitRevTable, arm_cfft_radix2_instance_q31::pTwiddle, and arm_cfft_radix2_instance_q31::twidCoefModifier.

-
@@ -707,20 +740,16 @@ Functions
-
Deprecated:
Do not use this function. It has been superseded by arm_cfft_f32 and will be removed in the future.
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_f32 and will be removed in the future.
Parameters
- - + +
[in]*Spoints to an instance of the floating-point Radix-4 CFFT/CIFFT structure.
[in,out]*pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place.
[in]Spoints to an instance of the floating-point Radix-4 CFFT/CIFFT structure
[in,out]pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place
-
Returns
none.
+
Returns
none
-

References arm_bitreversal_f32(), arm_radix4_butterfly_f32(), arm_radix4_butterfly_inverse_f32(), arm_cfft_radix4_instance_f32::bitReverseFlag, arm_cfft_radix4_instance_f32::bitRevFactor, arm_cfft_radix4_instance_f32::fftLen, arm_cfft_radix4_instance_f32::ifftFlag, arm_cfft_radix4_instance_f32::onebyfftLen, arm_cfft_radix4_instance_f32::pBitRevTable, arm_cfft_radix4_instance_f32::pTwiddle, and arm_cfft_radix4_instance_f32::twidCoefModifier.

- -

Referenced by main().

-
@@ -758,27 +787,34 @@ Functions
-
Deprecated:
Do not use this function. It has been superceded by arm_cfft_f32 and will be removed in the future.
Parameters
+
Deprecated:
Do not use this function. It has been superceded by arm_cfft_f32 and will be removed in the future.
Parameters
- - - - + + + +
[in,out]*Spoints to an instance of the floating-point CFFT/CIFFT structure.
[in]fftLenlength of the FFT.
[in]ifftFlagflag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
[in]bitReverseFlagflag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
[in,out]Spoints to an instance of the floating-point CFFT/CIFFT structure
[in]fftLenlength of the FFT
[in]ifftFlagflag that selects transform direction
    +
  • value = 0: forward transform
    • +
  • value = 1: inverse transform
    • +
+
[in]bitReverseFlagflag that enables / disables bit reversal of output
    +
  • value = 0: disables bit reversal of output
    • +
  • value = 1: enables bit reversal of output
    • +
+
-
Returns
The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if fftLen is not a supported value.
+
Returns
execution status +
-
Description:
-
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
+
Details
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
The parameter bitReverseFlag controls whether output is in normal order or bit reversed order. Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
The parameter fftLen Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
-

References ARM_MATH_ARGUMENT_ERROR, ARM_MATH_SUCCESS, armBitRevTable, arm_cfft_radix4_instance_f32::bitReverseFlag, arm_cfft_radix4_instance_f32::bitRevFactor, arm_cfft_radix4_instance_f32::fftLen, ifftFlag, arm_cfft_radix4_instance_f32::ifftFlag, arm_cfft_radix4_instance_f32::onebyfftLen, arm_cfft_radix4_instance_f32::pBitRevTable, arm_cfft_radix4_instance_f32::pTwiddle, status, arm_cfft_radix4_instance_f32::twidCoefModifier, and twiddleCoef.

- -

Referenced by arm_rfft_init_f32(), and main().

-
@@ -816,25 +852,34 @@ Functions
-
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q15 and will be removed
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q15 and will be removed in the future.
Parameters
- - - - + + + +
[in,out]*Spoints to an instance of the Q15 CFFT/CIFFT structure.
[in]fftLenlength of the FFT.
[in]ifftFlagflag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
[in]bitReverseFlagflag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
[in,out]Spoints to an instance of the Q15 CFFT/CIFFT structure
[in]fftLenlength of the FFT
[in]ifftFlagflag that selects transform direction
    +
  • value = 0: forward transform
    • +
  • value = 1: inverse transform
    • +
+
[in]bitReverseFlagflag that enables / disables bit reversal of output
    +
  • value = 0: disables bit reversal of output
    • +
  • value = 1: enables bit reversal of output
    • +
+
-
Returns
The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if fftLen is not a supported value.
+
Returns
execution status +
-
Description:
-
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
+
Details
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
The parameter bitReverseFlag controls whether output is in normal order or bit reversed order. Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
The parameter fftLen Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
-

References ARM_MATH_ARGUMENT_ERROR, ARM_MATH_SUCCESS, armBitRevTable, arm_cfft_radix4_instance_q15::bitReverseFlag, arm_cfft_radix4_instance_q15::bitRevFactor, arm_cfft_radix4_instance_q15::fftLen, ifftFlag, arm_cfft_radix4_instance_q15::ifftFlag, arm_cfft_radix4_instance_q15::pBitRevTable, arm_cfft_radix4_instance_q15::pTwiddle, status, arm_cfft_radix4_instance_q15::twidCoefModifier, and twiddleCoef_4096_q15.

-
@@ -872,25 +917,34 @@ Functions
-
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q31 and will be removed
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q31 and will be removed in the future.
Parameters
- + - - + +
[in,out]*Spoints to an instance of the Q31 CFFT/CIFFT structure.
[in,out]Spoints to an instance of the Q31 CFFT/CIFFT structure.
[in]fftLenlength of the FFT.
[in]ifftFlagflag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
[in]bitReverseFlagflag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
[in]ifftFlagflag that selects transform direction
    +
  • value = 0: forward transform
    • +
  • value = 1: inverse transform
    • +
+
[in]bitReverseFlagflag that enables / disables bit reversal of output
    +
  • value = 0: disables bit reversal of output
    • +
  • value = 1: enables bit reversal of output
    • +
+
-
Returns
The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if fftLen is not a supported value.
+
Returns
execution status +
-
Description:
-
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
+
Details
The parameter ifftFlag controls whether a forward or inverse transform is computed. Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
The parameter bitReverseFlag controls whether output is in normal order or bit reversed order. Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
The parameter fftLen Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
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References ARM_MATH_ARGUMENT_ERROR, ARM_MATH_SUCCESS, armBitRevTable, arm_cfft_radix4_instance_q31::bitReverseFlag, arm_cfft_radix4_instance_q31::bitRevFactor, arm_cfft_radix4_instance_q31::fftLen, ifftFlag, arm_cfft_radix4_instance_q31::ifftFlag, arm_cfft_radix4_instance_q31::pBitRevTable, arm_cfft_radix4_instance_q31::pTwiddle, status, arm_cfft_radix4_instance_q31::twidCoefModifier, and twiddleCoef_4096_q31.

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@@ -916,29 +970,26 @@ Functions
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Deprecated:
Do not use this function. It has been superseded by arm_cfft_q15 and will be removed
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q15 and will be removed in the future.
Parameters
- - + +
[in]*Spoints to an instance of the Q15 CFFT/CIFFT structure.
[in,out]*pSrcpoints to the complex data buffer. Processing occurs in-place.
[in]Spoints to an instance of the Q15 CFFT/CIFFT structure.
[in,out]pSrcpoints to the complex data buffer. Processing occurs in-place.
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Returns
none.
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Returns
none
-
Input and output formats:
-
Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process. Hence the output format is different for different FFT sizes. The input and output formats for different FFT sizes and number of bits to upscale are mentioned in the tables below for CFFT and CIFFT:
+
Input and output formats:
Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process. Hence the output format is different for different FFT sizes. The input and output formats for different FFT sizes and number of bits to upscale are mentioned in the tables below for CFFT and CIFFT:
CFFTQ15.gif
Input and Output Formats for Q15 CFFT
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+
CIFFTQ15.gif
Input and Output Formats for Q15 CIFFT
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References arm_bitreversal_q15(), arm_radix4_butterfly_inverse_q15(), arm_radix4_butterfly_q15(), arm_cfft_radix4_instance_q15::bitReverseFlag, arm_cfft_radix4_instance_q15::bitRevFactor, arm_cfft_radix4_instance_q15::fftLen, arm_cfft_radix4_instance_q15::ifftFlag, arm_cfft_radix4_instance_q15::pBitRevTable, arm_cfft_radix4_instance_q15::pTwiddle, and arm_cfft_radix4_instance_q15::twidCoefModifier.

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@@ -964,29 +1015,26 @@ Input and Output Formats for Q15 CIFFT
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Deprecated:
Do not use this function. It has been superseded by arm_cfft_q31 and will be removed
Parameters
+
Deprecated:
Do not use this function. It has been superseded by arm_cfft_q31 and will be removed in the future.
Parameters
- - + +
[in]*Spoints to an instance of the Q31 CFFT/CIFFT structure.
[in,out]*pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place.
[in]Spoints to an instance of the Q31 CFFT/CIFFT structure
[in,out]pSrcpoints to the complex data buffer of size 2*fftLen. Processing occurs in-place
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Returns
none.
+
Returns
none
-
Input and output formats:
-
Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process. Hence the output format is different for different FFT sizes. The input and output formats for different FFT sizes and number of bits to upscale are mentioned in the tables below for CFFT and CIFFT:
+
Input and output formats:
Internally input is downscaled by 2 for every stage to avoid saturations inside CFFT/CIFFT process. Hence the output format is different for different FFT sizes. The input and output formats for different FFT sizes and number of bits to upscale are mentioned in the tables below for CFFT and CIFFT:
CFFTQ31.gif
Input and Output Formats for Q31 CFFT
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+
CIFFTQ31.gif
Input and Output Formats for Q31 CIFFT
-

References arm_bitreversal_q31(), arm_radix4_butterfly_inverse_q31(), arm_radix4_butterfly_q31(), arm_cfft_radix4_instance_q31::bitReverseFlag, arm_cfft_radix4_instance_q31::bitRevFactor, arm_cfft_radix4_instance_q31::fftLen, arm_cfft_radix4_instance_q31::ifftFlag, arm_cfft_radix4_instance_q31::pBitRevTable, arm_cfft_radix4_instance_q31::pTwiddle, and arm_cfft_radix4_instance_q31::twidCoefModifier.

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@@ -994,7 +1042,7 @@ Input and Output Formats for Q31 CIFFT