STM CMSIS
Variables
Complex FFT Tables
Transform Functions

Variables

const uint16_t armBitRevTable [1024]
 
const float32_t twiddleCoef_16 [32]
 
const float32_t twiddleCoef_32 [64]
 
const float32_t twiddleCoef_64 [128]
 
const float32_t twiddleCoef_128 [256]
 
const float32_t twiddleCoef_256 [512]
 
const float32_t twiddleCoef_512 [1024]
 
const float32_t twiddleCoef_1024 [2048]
 
const float32_t twiddleCoef_2048 [4096]
 
const float32_t twiddleCoef_4096 [8192]
 
const q31_t twiddleCoef_16_q31 [24]
 
const q31_t twiddleCoef_32_q31 [48]
 
const q31_t twiddleCoef_64_q31 [96]
 
const q31_t twiddleCoef_128_q31 [192]
 
const q31_t twiddleCoef_256_q31 [384]
 
const q31_t twiddleCoef_512_q31 [768]
 
const q31_t twiddleCoef_1024_q31 [1536]
 
const q31_t twiddleCoef_2048_q31 [3072]
 
const q31_t twiddleCoef_4096_q31 [6144]
 
const q15_t twiddleCoef_16_q15 [24]
 
const q15_t twiddleCoef_32_q15 [48]
 
const q15_t twiddleCoef_64_q15 [96]
 
const q15_t twiddleCoef_128_q15 [192]
 
const q15_t twiddleCoef_256_q15 [384]
 
const q15_t twiddleCoef_512_q15 [768]
 
const q15_t twiddleCoef_1024_q15 [1536]
 
const q15_t twiddleCoef_2048_q15 [3072]
 
const q15_t twiddleCoef_4096_q15 [6144]
 

Detailed Description

Variable Documentation

◆ armBitRevTable

const uint16_t armBitRevTable[1024]
Pseudo code for Generation of Bit reversal Table is 
for(l=1;l <= N/4;l++)    
{    
  for(i=0;i<logN2;i++)    
  {     
    a[i]=l&(1<<i);    
  }    
  for(j=0; j<logN2; j++)    
  {    
    if (a[j]!=0)    
    y[l]+=(1<<((logN2-1)-j));    
  }    
  y[l] = y[l] >> 1;    
 }
where N = 4096 logN2 = 12
N is the maximum FFT Size supported

◆ twiddleCoef_1024

const float32_t twiddleCoef_1024[2048]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)    
{    
  twiddleCoef[2*i]= cos(i * 2*PI/(float)N);    
  twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 1024 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion

◆ twiddleCoef_1024_q15

const q15_t twiddleCoef_1024_q15[1536]
Example code for q15 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefq15[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefq15[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 1024 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))

◆ twiddleCoef_1024_q31

const q31_t twiddleCoef_1024_q31[1536]
Example code for Q31 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefQ31[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefQ31[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 1024 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))

◆ twiddleCoef_128

const float32_t twiddleCoef_128[256]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)    
{    
  twiddleCoef[2*i]= cos(i * 2*PI/(float)N);    
  twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 128 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion

◆ twiddleCoef_128_q15

const q15_t twiddleCoef_128_q15[192]
Example code for q15 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefq15[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefq15[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 128 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))

◆ twiddleCoef_128_q31

const q31_t twiddleCoef_128_q31[192]
Example code for Q31 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefQ31[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefQ31[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 128 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))

◆ twiddleCoef_16

const float32_t twiddleCoef_16[32]
Initial value:
= {
1.000000000f, 0.000000000f,
0.923879533f, 0.382683432f,
0.707106781f, 0.707106781f,
0.382683432f, 0.923879533f,
0.000000000f, 1.000000000f,
-0.382683432f, 0.923879533f,
-0.707106781f, 0.707106781f,
-0.923879533f, 0.382683432f,
-1.000000000f, 0.000000000f,
-0.923879533f, -0.382683432f,
-0.707106781f, -0.707106781f,
-0.382683432f, -0.923879533f,
-0.000000000f, -1.000000000f,
0.382683432f, -0.923879533f,
0.707106781f, -0.707106781f,
0.923879533f, -0.382683432f
}
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)    
{    
  twiddleCoef[2*i]= cos(i * 2*PI/(float)N);    
  twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 16 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion

◆ twiddleCoef_16_q15

const q15_t twiddleCoef_16_q15[24]
Initial value:
= {
0x7FFF, 0x0000,
0x7641, 0x30FB,
0x5A82, 0x5A82,
0x30FB, 0x7641,
0x0000, 0x7FFF,
0xCF04, 0x7641,
0xA57D, 0x5A82,
0x89BE, 0x30FB,
0x8000, 0x0000,
0x89BE, 0xCF04,
0xA57D, 0xA57D,
0xCF04, 0x89BE
}
Example code for q15 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefq15[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefq15[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 16 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))

◆ twiddleCoef_16_q31

const q31_t twiddleCoef_16_q31[24]
Initial value:
= {
0x7FFFFFFF, 0x00000000,
0x7641AF3C, 0x30FBC54D,
0x5A82799A, 0x5A82799A,
0x30FBC54D, 0x7641AF3C,
0x00000000, 0x7FFFFFFF,
0xCF043AB2, 0x7641AF3C,
0xA57D8666, 0x5A82799A,
0x89BE50C3, 0x30FBC54D,
0x80000000, 0x00000000,
0x89BE50C3, 0xCF043AB2,
0xA57D8666, 0xA57D8666,
0xCF043AB2, 0x89BE50C3
}
Example code for Q31 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefQ31[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefQ31[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 16 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))

◆ twiddleCoef_2048

const float32_t twiddleCoef_2048[4096]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)    
{    
  twiddleCoef[2*i]= cos(i * 2*PI/(float)N);    
  twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 2048 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion

◆ twiddleCoef_2048_q15

const q15_t twiddleCoef_2048_q15[3072]
Example code for q15 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefq15[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefq15[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 2048 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))

◆ twiddleCoef_2048_q31

const q31_t twiddleCoef_2048_q31[3072]
Example code for Q31 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefQ31[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefQ31[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 2048 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))

◆ twiddleCoef_256

const float32_t twiddleCoef_256[512]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)    
{    
  twiddleCoef[2*i]= cos(i * 2*PI/(float)N);    
  twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 256 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion

◆ twiddleCoef_256_q15

const q15_t twiddleCoef_256_q15[384]
Example code for q15 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefq15[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefq15[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 256 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))

◆ twiddleCoef_256_q31

const q31_t twiddleCoef_256_q31[384]
Example code for Q31 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefQ31[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefQ31[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 256 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))

◆ twiddleCoef_32

const float32_t twiddleCoef_32[64]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)    
{    
  twiddleCoef[2*i]= cos(i * 2*PI/(float)N);    
  twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 32 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion

◆ twiddleCoef_32_q15

const q15_t twiddleCoef_32_q15[48]
Initial value:
= {
0x7FFF, 0x0000,
0x7D8A, 0x18F8,
0x7641, 0x30FB,
0x6A6D, 0x471C,
0x5A82, 0x5A82,
0x471C, 0x6A6D,
0x30FB, 0x7641,
0x18F8, 0x7D8A,
0x0000, 0x7FFF,
0xE707, 0x7D8A,
0xCF04, 0x7641,
0xB8E3, 0x6A6D,
0xA57D, 0x5A82,
0x9592, 0x471C,
0x89BE, 0x30FB,
0x8275, 0x18F8,
0x8000, 0x0000,
0x8275, 0xE707,
0x89BE, 0xCF04,
0x9592, 0xB8E3,
0xA57D, 0xA57D,
0xB8E3, 0x9592,
0xCF04, 0x89BE,
0xE707, 0x8275
}
Example code for q15 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefq15[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefq15[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 32 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))

◆ twiddleCoef_32_q31

const q31_t twiddleCoef_32_q31[48]
Initial value:
= {
0x7FFFFFFF, 0x00000000,
0x7D8A5F3F, 0x18F8B83C,
0x7641AF3C, 0x30FBC54D,
0x6A6D98A4, 0x471CECE6,
0x5A82799A, 0x5A82799A,
0x471CECE6, 0x6A6D98A4,
0x30FBC54D, 0x7641AF3C,
0x18F8B83C, 0x7D8A5F3F,
0x00000000, 0x7FFFFFFF,
0xE70747C3, 0x7D8A5F3F,
0xCF043AB2, 0x7641AF3C,
0xB8E31319, 0x6A6D98A4,
0xA57D8666, 0x5A82799A,
0x9592675B, 0x471CECE6,
0x89BE50C3, 0x30FBC54D,
0x8275A0C0, 0x18F8B83C,
0x80000000, 0x00000000,
0x8275A0C0, 0xE70747C3,
0x89BE50C3, 0xCF043AB2,
0x9592675B, 0xB8E31319,
0xA57D8666, 0xA57D8666,
0xB8E31319, 0x9592675B,
0xCF043AB2, 0x89BE50C3,
0xE70747C3, 0x8275A0C0
}
Example code for Q31 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefQ31[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefQ31[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 32 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))

◆ twiddleCoef_4096

const float32_t twiddleCoef_4096[8192]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)    
{    
  twiddleCoef[2*i]= cos(i * 2*PI/(float)N);    
  twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 4096 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion

◆ twiddleCoef_4096_q15

const q15_t twiddleCoef_4096_q15[6144]
Example code for q15 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefq15[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefq15[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 4096 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))

◆ twiddleCoef_4096_q31

const q31_t twiddleCoef_4096_q31[6144]
Example code for Q31 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefQ31[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefQ31[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 4096 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))

◆ twiddleCoef_512

const float32_t twiddleCoef_512[1024]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)    
{    
  twiddleCoef[2*i]= cos(i * 2*PI/(float)N);    
  twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 512 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion

◆ twiddleCoef_512_q15

const q15_t twiddleCoef_512_q15[768]
Example code for q15 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefq15[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefq15[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 512 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))

◆ twiddleCoef_512_q31

const q31_t twiddleCoef_512_q31[768]
Example code for Q31 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefQ31[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefQ31[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 512 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))

◆ twiddleCoef_64

const float32_t twiddleCoef_64[128]
Example code for Floating-point Twiddle factors Generation: 
for(i = 0; i< N/; i++)    
{    
  twiddleCoef[2*i]= cos(i * 2*PI/(float)N);    
  twiddleCoef[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 64 and PI = 3.14159265358979
Cos and Sin values are in interleaved fashion

◆ twiddleCoef_64_q15

const q15_t twiddleCoef_64_q15[96]
Example code for q15 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefq15[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefq15[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 64 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to q15(Fixed point 1.15): round(twiddleCoefq15(i) * pow(2, 15))

◆ twiddleCoef_64_q31

const q31_t twiddleCoef_64_q31[96]
Example code for Q31 Twiddle factors Generation:: 
for(i = 0; i< 3N/4; i++)    
{    
   twiddleCoefQ31[2*i]= cos(i * 2*PI/(float)N);    
   twiddleCoefQ31[2*i+1]= sin(i * 2*PI/(float)N);    
}
where N = 64 and PI = 3.14159265358979
Cos and Sin values are interleaved fashion
Convert Floating point to Q31(Fixed point 1.31): round(twiddleCoefQ31(i) * pow(2, 31))