#include "arm_math.h" #include "math_helper.h" #include #define BLOCK_SIZE 32 #define NUM_BLOCKS 10 #define TEST_LENGTH_SAMPLES (BLOCK_SIZE * NUM_BLOCKS) #define SNR_THRESHOLD_F32 140.0f #define NUM_TAPS 29 /* ------------------------------------------------------------------- * The input signal and reference output (computed with MATLAB) * are defined externally in arm_fir_lpf_data.c. * ------------------------------------------------------------------- */ extern float32_t testInput_f32_1kHz_15kHz[TEST_LENGTH_SAMPLES]; extern float32_t refOutput[TEST_LENGTH_SAMPLES]; /* ------------------------------------------------------------------- * Declare State buffer of size (numTaps + blockSize - 1) * ------------------------------------------------------------------- */ static float32_t firStateF32[BLOCK_SIZE + NUM_TAPS - 1]; /* ---------------------------------------------------------------------- * FIR Coefficients buffer generated using fir1() MATLAB function. * fir1(28, 6/24) * ------------------------------------------------------------------- */ const float32_t firCoeffs32[NUM_TAPS] = { -0.0018225230f, -0.0015879294f, +0.0000000000f, +0.0036977508f, +0.0080754303f, +0.0085302217f, -0.0000000000f, -0.0173976984f, -0.0341458607f, -0.0333591565f, +0.0000000000f, +0.0676308395f, +0.1522061835f, +0.2229246956f, +0.2504960933f, +0.2229246956f, +0.1522061835f, +0.0676308395f, +0.0000000000f, -0.0333591565f, -0.0341458607f, -0.0173976984f, -0.0000000000f, +0.0085302217f, +0.0080754303f, +0.0036977508f, +0.0000000000f, -0.0015879294f, -0.0018225230f }; /* ---------------------------------------------------------------------- * FIR LPF Example * ------------------------------------------------------------------- */ int main(void) { /* Call FIR init function to initialize the instance structure. */ arm_fir_instance_f32 S; arm_fir_init_f32(&S, NUM_TAPS, (float32_t *)&firCoeffs32[0], &firStateF32[0], BLOCK_SIZE); /* ---------------------------------------------------------------------- * Call the FIR process function for every blockSize samples * ------------------------------------------------------------------- */ for (uint32_t i=0; i < NUM_BLOCKS; i++) { float32_t* signal = testInput_f32_1kHz_15kHz + (i * BLOCK_SIZE); arm_fir_f32(&S, signal, signal, BLOCK_SIZE); } /* ---------------------------------------------------------------------- * Compare the generated output against the reference output computed * in MATLAB. * ------------------------------------------------------------------- */ float32_t snr = arm_snr_f32(refOutput, testInput_f32_1kHz_15kHz, TEST_LENGTH_SAMPLES); printf("snr: %f\n\r", snr); if (snr < SNR_THRESHOLD_F32) { printf("Failed\n\r"); } else { printf("Success\n\r"); } }