arm_linear_interp_example_f32.c

/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        29. November 2010
* $Revision:    V1.0.3
*
* Project:      CMSIS DSP Library
* Title:        arm_linear_interp_example_f32.c
*
* Description:  Example code demonstrating usage of sin function
*               and uses linear interpolation to get higher precision
*
* Target Processor: Cortex-M4/Cortex-M3
*
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.1 2010/10/05 KK
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20 KK
*    Production release and review comments incorporated.
* ------------------------------------------------------------------- */

#include "arm_math.h"
#include "math_helper.h"

#define SNR_THRESHOLD           90
#define TEST_LENGTH_SAMPLES     10
#define XSPACING               (0.00005f)

/* ----------------------------------------------------------------------
* Test input data for F32 SIN function
* Generated by the MATLAB rand() function
* randn('state', 0)
* xi = (((1/4.18318581819710)* randn(blockSize, 1) * 2* pi));
* --------------------------------------------------------------------*/
float32_t testInputSin_f32[TEST_LENGTH_SAMPLES] =
{
   -0.649716504673081170, -2.501723745497831200,
    0.188250329003310100,  0.432092748487532540,
   -1.722010988459680800,  1.788766476323060600,
    1.786136060975809500, -0.056525543169408797,
    0.491596272728153760,  0.262309671126153390
};

/*------------------------------------------------------------------------------
*  Reference out of SIN F32 function for Block Size = 10
*  Calculated from sin(testInputSin_f32)
*------------------------------------------------------------------------------*/
float32_t testRefSinOutput32_f32[TEST_LENGTH_SAMPLES] =
{
   -0.604960695383043530, -0.597090287967934840,
    0.187140422442966500,  0.418772124875992690,
   -0.988588831792106880,  0.976338412038794010,
    0.976903856413481100, -0.056495446835214236,
    0.472033731854734240,  0.259311907228582830
};

/*------------------------------------------------------------------------------
*  Method 1: Test out Buffer Calculated from Cubic Interpolation
*------------------------------------------------------------------------------*/
float32_t testOutput[TEST_LENGTH_SAMPLES];

/*------------------------------------------------------------------------------
*  Method 2: Test out buffer Calculated from Linear Interpolation
*------------------------------------------------------------------------------*/
float32_t testLinIntOutput[TEST_LENGTH_SAMPLES];

/*------------------------------------------------------------------------------
*  External table used for linear interpolation
*------------------------------------------------------------------------------*/
extern const float arm_linear_interep_table[188495];

/* ----------------------------------------------------------------------
* Global Variables for caluclating SNR's for Method1 & Method 2
* ------------------------------------------------------------------- */
float32_t snr1;
float32_t snr2;

/* ----------------------------------------------------------------------------
* Calculation of Sine values from Cubic Interpolation and Linear interpolation
* ---------------------------------------------------------------------------- */
int32_t main(void)
{
   uint32_t i;
   arm_status status;

   arm_linear_interp_instance_f32 S = {188495, -3.141592653589793238, XSPACING, (float32_t *)&arm_linear_interep_table[0]};

   /*------------------------------------------------------------------------------
   *  Method 1: Test out Calculated from Cubic Interpolation
   *------------------------------------------------------------------------------*/
   for(i=0; i< TEST_LENGTH_SAMPLES; i++)
   {
      testOutput[i] = arm_sin_f32(testInputSin_f32[i]);
   }

   /*------------------------------------------------------------------------------
   *  Method 2: Test out Calculated from Cubic Interpolation and Linear interpolation
   *------------------------------------------------------------------------------*/

   for(i=0; i< TEST_LENGTH_SAMPLES; i++)
   {
        testLinIntOutput[i] = arm_linear_interp_f32(&S, testInputSin_f32[i]);
   }

   /*------------------------------------------------------------------------------
   *  SNR calculation for method 1
   *------------------------------------------------------------------------------*/
   snr1 = arm_snr_f32(testRefSinOutput32_f32, testOutput, 2);

   /*------------------------------------------------------------------------------
   *  SNR calculation for method 2
   *------------------------------------------------------------------------------*/
   snr2 = arm_snr_f32(testRefSinOutput32_f32, testLinIntOutput, 2);

   /*------------------------------------------------------------------------------
   *                                    Initialise status depending on SNR calculations
   *------------------------------------------------------------------------------*/
   if( snr2 > snr1)
   {
      status = ARM_MATH_SUCCESS;
   }
   else
   {
      status = ARM_MATH_TEST_FAILURE;
   }

   /* ----------------------------------------------------------------------
   ** Loop here if the signals fail the PASS check.
   ** This denotes a test failure
   ** ------------------------------------------------------------------- */
   if( status != ARM_MATH_SUCCESS)
   {
      while(1);
   }

   while(1);                             /* main function does not return */
}