Emilio Monti
Example FIR filter using the CMSIS DSP API
Revision 2:9ccaf6885ced, committed 2013-01-08
- Comitter:
- emilmont
- Date:
- Tue Jan 08 17:00:49 2013 +0000
- Parent:
- 1:9442dff3bfdc
- Commit message:
- Update example to latest mbed-dsp library
Changed in this revision
diff -r 9442dff3bfdc -r 9ccaf6885ced data.cpp
--- a/data.cpp Mon Mar 12 12:00:25 2012 +0000
+++ b/data.cpp Tue Jan 08 17:00:49 2013 +0000
@@ -1,7 +1,11 @@
#include "arm_math.h"
-// Test input signal contains 1000Hz + 15000 Hz
-float32_t signal[320] = {
+/* ----------------------------------------------------------------------
+** Test input signal contains 1000Hz + 15000 Hz
+** ------------------------------------------------------------------- */
+
+float32_t testInput_f32_1kHz_15kHz[320] =
+{
+0.0000000000f, +0.5924659585f, -0.0947343455f, +0.1913417162f, +1.0000000000f, +0.4174197128f, +0.3535533906f, +1.2552931065f,
+0.8660254038f, +0.4619397663f, +1.3194792169f, +1.1827865776f, +0.5000000000f, +1.1827865776f, +1.3194792169f, +0.4619397663f,
+0.8660254038f, +1.2552931065f, +0.3535533906f, +0.4174197128f, +1.0000000000f, +0.1913417162f, -0.0947343455f, +0.5924659585f,
@@ -44,7 +48,8 @@
+0.0000000000f, -0.5924659585f, +0.0947343455f, -0.1913417162f, -1.0000000000f, -0.4174197128f, -0.3535533906f, -1.2552931065f,
};
-float32_t filtered_signal[320] = {
+float32_t refOutput[320] =
+{
+0.0000000000f, -0.0010797829f, -0.0007681386f, -0.0001982932f, +0.0000644313f, +0.0020854271f, +0.0036891871f, +0.0015855941f,
-0.0026280805f, -0.0075907658f, -0.0119390538f, -0.0086665968f, +0.0088981202f, +0.0430539279f, +0.0974468742f, +0.1740405600f,
+0.2681416601f, +0.3747720089f, +0.4893362230f, +0.6024154672f, +0.7058740791f, +0.7968348987f, +0.8715901940f, +0.9277881093f,
diff -r 9442dff3bfdc -r 9ccaf6885ced main.cpp
--- a/main.cpp Mon Mar 12 12:00:25 2012 +0000
+++ b/main.cpp Tue Jan 08 17:00:49 2013 +0000
@@ -1,23 +1,32 @@
-#include <stdio.h>
#include "arm_math.h"
#include "math_helper.h"
+#include <stdio.h>
#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
-#define SNR_THRESHOLD_F32 140.0f
+
+/* -------------------------------------------------------------------
+ * 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];
-// The input signal and reference output
-extern float32_t signal[TEST_LENGTH_SAMPLES];
-extern float32_t filtered_signal[TEST_LENGTH_SAMPLES];
+/* -------------------------------------------------------------------
+ * Declare State buffer of size (numTaps + blockSize - 1)
+ * ------------------------------------------------------------------- */
+static float32_t firStateF32[BLOCK_SIZE + NUM_TAPS - 1];
-// 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] = {
+/* ----------------------------------------------------------------------
+ * 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,
@@ -26,23 +35,31 @@
+0.0036977508f, +0.0000000000f, -0.0015879294f, -0.0018225230f
};
+/* ----------------------------------------------------------------------
+ * FIR LPF Example
+ * ------------------------------------------------------------------- */
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 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 BLOCK_SIZE samples
+ /* ----------------------------------------------------------------------
+ * Call the FIR process function for every blockSize samples
+ * ------------------------------------------------------------------- */
for (uint32_t i=0; i < NUM_BLOCKS; i++) {
- float32_t* signal_buffer = signal + (i * BLOCK_SIZE);
- arm_fir_f32(&fir, signal_buffer, signal_buffer, BLOCK_SIZE);
+ 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
- float32_t snr = arm_snr_f32(filtered_signal, signal, TEST_LENGTH_SAMPLES);
+ /* ----------------------------------------------------------------------
+ * 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");
}
-}
+}
diff -r 9442dff3bfdc -r 9ccaf6885ced mbed-dsp.lib --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-dsp.lib Tue Jan 08 17:00:49 2013 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed-dsp/#fdd22bb7aa52
diff -r 9442dff3bfdc -r 9ccaf6885ced mbed.bld --- a/mbed.bld Mon Mar 12 12:00:25 2012 +0000 +++ b/mbed.bld Tue Jan 08 17:00:49 2013 +0000 @@ -1,1 +1,1 @@ -http://mbed.org/users/mbed_official/code/mbed/builds/737756e0b479 +http://mbed.org/users/mbed_official/code/mbed/builds/71b101360fb9 \ No newline at end of file