Emilio Monti
Example FIR filter using the draft mbed DSP API
Revision 4:82ad711603c2, committed 2013-01-08
- Comitter:
- emilmont
- Date:
- Tue Jan 08 16:54:33 2013 +0000
- Parent:
- 3:15d0df9ab05b
- Commit message:
- Update example to latest mbed-dsp library
Changed in this revision
--- a/main.cpp Mon Mar 12 12:53:03 2012 +0000
+++ b/main.cpp Tue Jan 08 16:54:33 2013 +0000
@@ -10,11 +10,11 @@
#define SNR_THRESHOLD_F32 (50.0f)
float32_t expected_output[TEST_LENGTH_SAMPLES];
-float32_t signal[TEST_LENGTH_SAMPLES];
+float32_t output[TEST_LENGTH_SAMPLES];
-/* FIR Coefficients buffer */
+/* FIR Coefficients buffer generated using fir1() MATLAB function: fir1(28, 6/24) */
#define NUM_TAPS 29
-const float32_t fir_coeff[NUM_TAPS] = {
+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,
@@ -26,24 +26,24 @@
#define DELAY (WARMUP/2)
int main() {
- Sine_f32 sine_1K( 1000, SAMPLE_RATE, 1.0);
- Sine_f32 sine_15K(15000, SAMPLE_RATE, 0.5);
- FIR_f32<NUM_TAPS> fir(fir_coeff);
+ Sine_f32 sine_1KHz( 1000, SAMPLE_RATE, 1.0);
+ Sine_f32 sine_15KHz(15000, SAMPLE_RATE, 0.5);
+ FIR_f32<NUM_TAPS> fir(firCoeffs32);
- for (int i=0; i<NUM_BLOCKS; i++) {
- float32_t *signal_buffer = signal + i*BLOCK_SIZE;
- sine_1K.process(signal_buffer);
- sine_15K.process(signal_buffer);
- fir.process(signal_buffer);
+ float32_t buffer_a[BLOCK_SIZE];
+ float32_t buffer_b[BLOCK_SIZE];
+ for (float32_t *sgn=output; sgn<(output+TEST_LENGTH_SAMPLES); sgn += BLOCK_SIZE) {
+ sine_1KHz.generate(buffer_a); // Generate a 1KHz sine wave
+ sine_15KHz.process(buffer_a, buffer_b); // Add a 15KHz sine wave
+ fir.process(buffer_b, sgn); // FIR low pass filter: 6KHz cutoff
}
- sine_1K.reset();
- for (int i=0; i<NUM_BLOCKS; i++) {
- float32_t *signal_buffer = expected_output + i*BLOCK_SIZE;
- sine_1K.process(signal_buffer);
+ sine_1KHz.reset();
+ for (float32_t *sgn=expected_output; sgn<(expected_output+TEST_LENGTH_SAMPLES); sgn += BLOCK_SIZE) {
+ sine_1KHz.generate(sgn); // Generate a 1KHz sine wave
}
- float snr = arm_snr_f32(&expected_output[DELAY-1], &signal[WARMUP-1], TEST_LENGTH_SAMPLES-WARMUP);
+ float snr = arm_snr_f32(&expected_output[DELAY-1], &output[WARMUP-1], TEST_LENGTH_SAMPLES-WARMUP);
printf("snr: %f\n\r", snr);
if (snr < SNR_THRESHOLD_F32) {
printf("Failed\n\r");
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/mbed-dsp.lib Tue Jan 08 16:54:33 2013 +0000 @@ -0,0 +1,1 @@ +http://mbed.org/users/mbed_official/code/mbed-dsp/#fdd22bb7aa52
--- a/mbed.bld Mon Mar 12 12:53:03 2012 +0000 +++ b/mbed.bld Tue Jan 08 16:54:33 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
--- a/mbed_dsp.lib Mon Mar 12 12:53:03 2012 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,1 +0,0 @@ -http://mbed.org/users/emilmont/code/mbed_dsp/#8679f8bc80b6