Emilio Monti / Mbed 2 deprecated cmsis_dsp_fir

Example FIR filter using the CMSIS DSP API

Dependencies:   mbed mbed-dsp

main.cpp@1:9442dff3bfdc, 2012-03-12 (annotated)

Committer:
emilmont
Date:
Mon Mar 12 12:00:25 2012 +0000
Revision:
1:9442dff3bfdc
Parent:
0:840b7af4eace
Child:
2:9ccaf6885ced

        

        
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#include <stdio.h>





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#include "arm_math.h" 





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#include "math_helper.h" 





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#define BLOCK_SIZE          32





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#define NUM_BLOCKS          10





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#define TEST_LENGTH_SAMPLES (BLOCK_SIZE * NUM_BLOCKS)





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#define NUM_TAPS            29





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#define SNR_THRESHOLD_F32   140.0f





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// The input signal and reference output





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extern float32_t          signal[TEST_LENGTH_SAMPLES]; 





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extern float32_t filtered_signal[TEST_LENGTH_SAMPLES]; 





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// Declare FIR State buffer of size (numTaps + blockSize - 1)





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float32_t fir_state[BLOCK_SIZE + NUM_TAPS - 1]; 





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// FIR Coefficients





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const float32_t fir_coeff[NUM_TAPS] = { 





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    -0.0018225230f, -0.0015879294f, +0.0000000000f, +0.0036977508f, +0.0080754303f,





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    +0.0085302217f, -0.0000000000f, -0.0173976984f, -0.0341458607f, -0.0333591565f,





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    +0.0000000000f, +0.0676308395f, +0.1522061835f, +0.2229246956f, +0.2504960933f,





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    +0.2229246956f, +0.1522061835f, +0.0676308395f, +0.0000000000f, -0.0333591565f,





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    -0.0341458607f, -0.0173976984f, -0.0000000000f, +0.0085302217f, +0.0080754303f,





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    +0.0036977508f, +0.0000000000f, -0.0015879294f, -0.0018225230f





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};





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int32_t main(void) { 





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    // Call FIR init function to initialize the instance structure.





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    arm_fir_instance_f32 fir;





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    arm_fir_init_f32(&fir, NUM_TAPS, (float32_t *)fir_coeff, fir_state, BLOCK_SIZE); 





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    // Call the FIR process function for every BLOCK_SIZE samples  





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    for (uint32_t i=0; i < NUM_BLOCKS; i++) {





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        float32_t* signal_buffer =  signal + (i * BLOCK_SIZE);





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        arm_fir_f32(&fir, signal_buffer, signal_buffer, BLOCK_SIZE);





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    } 





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    // Compare the generated output against the reference





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    float32_t snr = arm_snr_f32(filtered_signal, signal, TEST_LENGTH_SAMPLES);





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    printf("snr: %f\n\r", snr);





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    if (snr < SNR_THRESHOLD_F32) {





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        printf("Failed\n\r");





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    } else {





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        printf("Success\n\r");





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    }





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}