Emilio Monti
/
cmsis_dsp_fir
Example FIR filter using the CMSIS DSP API
Diff: main.cpp
- Revision:
- 0:840b7af4eace
- Child:
- 1:9442dff3bfdc
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/main.cpp Mon Mar 12 11:34:49 2012 +0000 @@ -0,0 +1,48 @@ +#include <stdio.h> +#include "arm_math.h" +#include "math_helper.h" + +#define BLOCK_SIZE 32 +#define NUM_BLOCKS 10 +#define TEST_LENGTH_SAMPLES (BLOCK_SIZE * NUM_BLOCKS) + +#define NUM_TAPS 29 +#define SNR_THRESHOLD_F32 140.0f + +// The input signal and reference output +extern float32_t output[TEST_LENGTH_SAMPLES]; +extern float32_t expected_output[TEST_LENGTH_SAMPLES]; + +// Declare FIR State buffer of size (numTaps + blockSize - 1) +float32_t fir_state[BLOCK_SIZE + NUM_TAPS - 1]; + +// FIR Coefficients +const float32_t fir_coeff[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 +}; + +int32_t main(void) { + // Call FIR init function to initialize the instance structure. + arm_fir_instance_f32 fir; + arm_fir_init_f32(&fir, NUM_TAPS, (float32_t *)fir_coeff, fir_state, BLOCK_SIZE); + + // Call the FIR process function for every BLOCK_SIZE samples + for (uint32_t i=0; i < NUM_BLOCKS; i++) { + float32_t* signal = output + (i * BLOCK_SIZE); + arm_fir_f32(&fir, signal, signal, BLOCK_SIZE); + } + + // Compare the generated output against the reference + float32_t snr = arm_snr_f32(expected_output, output, TEST_LENGTH_SAMPLES); + printf("snr: %f\n\r", snr); + if (snr < SNR_THRESHOLD_F32) { + printf("Failed\n\r"); + } else { + printf("Success\n\r"); + } +}