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-rw-r--r--src/common/Makefile.am2
-rw-r--r--src/common/call.c2
-rw-r--r--src/common/emphasis.c6
-rw-r--r--src/common/emphasis.h2
-rw-r--r--src/common/filter.c99
-rw-r--r--src/common/filter.h14
-rw-r--r--src/common/fm_modulation.c10
-rw-r--r--src/common/fm_modulation.h2
-rw-r--r--src/common/iir_filter.c133
-rw-r--r--src/common/iir_filter.h16
-rw-r--r--src/common/samplerate.c10
-rw-r--r--src/common/samplerate.h8
-rw-r--r--src/common/sdr.c2
-rw-r--r--src/common/sender.c2
14 files changed, 172 insertions, 136 deletions
diff --git a/src/common/Makefile.am b/src/common/Makefile.am
index 095665e..fa26d21 100644
--- a/src/common/Makefile.am
+++ b/src/common/Makefile.am
@@ -12,7 +12,7 @@ libcommon_a_SOURCES = \
../common/goertzel.c \
../common/jitter.c \
../common/loss.c \
- ../common/filter.c \
+ ../common/iir_filter.c \
../common/dtmf.c \
../common/samplerate.c \
../common/call.c \
diff --git a/src/common/call.c b/src/common/call.c
index ff6128e..4452c5e 100644
--- a/src/common/call.c
+++ b/src/common/call.c
@@ -497,7 +497,7 @@ int call_init(const char *station_id, const char *audiodev, int samplerate, int
if (!audiodev[0])
return 0;
- rc = init_samplerate(&call.srstate, 8000.0, (double)samplerate);
+ rc = init_samplerate(&call.srstate, 8000.0, (double)samplerate, 3300.0);
if (rc < 0) {
PDEBUG(DSENDER, DEBUG_ERROR, "Failed to init sample rate conversion!\n");
goto error;
diff --git a/src/common/emphasis.c b/src/common/emphasis.c
index 3fb6679..241deee 100644
--- a/src/common/emphasis.c
+++ b/src/common/emphasis.c
@@ -22,7 +22,7 @@
#include <string.h>
#include <math.h>
#include "sample.h"
-#include "filter.h"
+#include "iir_filter.h"
#include "emphasis.h"
#include "debug.h"
@@ -66,7 +66,7 @@ int init_emphasis(emphasis_t *state, int samplerate, double cut_off)
state->d.factor = factor;
state->d.amp = 1.0;
- filter_highpass_init(&state->d.hp, CUT_OFF_H, samplerate, 1);
+ iir_highpass_init(&state->d.hp, CUT_OFF_H, samplerate, 1);
/* calibrate amplification to be neutral at 1000 Hz */
gen_sine(test_samples, sizeof(test_samples) / sizeof(test_samples[0]), samplerate, 1000.0);
@@ -128,6 +128,6 @@ void de_emphasis(emphasis_t *state, sample_t *samples, int num)
/* high pass filter to remove DC and low frequencies */
void dc_filter(emphasis_t *state, sample_t *samples, int num)
{
- filter_process(&state->d.hp, samples, num);
+ iir_process(&state->d.hp, samples, num);
}
diff --git a/src/common/emphasis.h b/src/common/emphasis.h
index 283afb1..235e3ce 100644
--- a/src/common/emphasis.h
+++ b/src/common/emphasis.h
@@ -5,7 +5,7 @@ typedef struct emphasis {
double amp;
} p;
struct {
- filter_t hp;
+ iir_filter_t hp;
double y_last;
double factor;
double amp;
diff --git a/src/common/filter.c b/src/common/filter.c
deleted file mode 100644
index 0a5c0dd..0000000
--- a/src/common/filter.c
+++ /dev/null
@@ -1,99 +0,0 @@
-/* cut-off filter (biquad) based on Nigel Redmon (www.earlevel.com)
- *
- * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
- * All Rights Reserved
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-#include <stdio.h>
-#include <stdint.h>
-#include <string.h>
-#include <stdlib.h>
-#include <math.h>
-#include "sample.h"
-#include "filter.h"
-
-#define PI M_PI
-
-void filter_lowpass_init(filter_t *bq, double frequency, int samplerate, int iterations)
-{
- double Fc, Q, K, norm;
-
- if (iterations > 64) {
- fprintf(stderr, "%s failed: too many iterations, please fix!\n", __func__);
- abort();
- }
-
- memset(bq, 0, sizeof(*bq));
- bq->iter = iterations;
- Q = pow(sqrt(0.5), 1.0 / (double)iterations); /* 0.7071 @ 1 iteration */
- Fc = frequency / (double)samplerate;
- K = tan(PI * Fc);
- norm = 1 / (1 + K / Q + K * K);
- bq->a0 = K * K * norm;
- bq->a1 = 2 * bq->a0;
- bq->a2 = bq->a0;
- bq->b1 = 2 * (K * K - 1) * norm;
- bq->b2 = (1 - K / Q + K * K) * norm;
-}
-
-void filter_highpass_init(filter_t *bq, double frequency, int samplerate, int iterations)
-{
- double Fc, Q, K, norm;
-
- memset(bq, 0, sizeof(*bq));
- bq->iter = iterations;
- Q = pow(sqrt(0.5), 1.0 / (double)iterations); /* 0.7071 @ 1 iteration */
- Fc = frequency / (double)samplerate;
- K = tan(PI * Fc);
- norm = 1 / (1 + K / Q + K * K);
- bq->a0 = 1 * norm;
- bq->a1 = -2 * bq->a0;
- bq->a2 = bq->a0;
- bq->b1 = 2 * (K * K - 1) * norm;
- bq->b2 = (1 - K / Q + K * K) * norm;
-}
-
-void filter_process(filter_t *bq, sample_t *samples, int length)
-{
- double a0, a1, a2, b1, b2;
- double *z1, *z2;
- double in, out;
- int iterations = bq->iter;
- int i, j;
-
- /* get states */
- a0 = bq->a0;
- a1 = bq->a1;
- a2 = bq->a2;
- b1 = bq->b1;
- b2 = bq->b2;
-
- z1 = bq->z1;
- z2 = bq->z2;
-
- /* process filter */
- for (i = 0; i < length; i++) {
- in = *samples;
- for (j = 0; j < iterations; j++) {
- out = in * a0 + z1[j];
- z1[j] = in * a1 + z2[j] - b1 * out;
- z2[j] = in * a2 - b2 * out;
- in = out;
- }
- *samples++ = in;
- }
-}
-
diff --git a/src/common/filter.h b/src/common/filter.h
deleted file mode 100644
index 9f33fe2..0000000
--- a/src/common/filter.h
+++ /dev/null
@@ -1,14 +0,0 @@
-#ifndef _FILTER_H
-#define _FILTER_H
-
-typedef struct filter {
- int iter;
- double a0, a1, a2, b1, b2;
- double z1[64], z2[64];
-} filter_t;
-
-void filter_lowpass_init(filter_t *bq, double frequency, int samplerate, int iterations);
-void filter_highpass_init(filter_t *bq, double frequency, int samplerate, int iterations);
-void filter_process(filter_t *bq, sample_t *samples, int length);
-
-#endif /* _FILTER_H */
diff --git a/src/common/fm_modulation.c b/src/common/fm_modulation.c
index dca88b0..aaf7e2c 100644
--- a/src/common/fm_modulation.c
+++ b/src/common/fm_modulation.c
@@ -23,7 +23,7 @@
#include <string.h>
#include <math.h>
#include "sample.h"
-#include "filter.h"
+#include "iir_filter.h"
#include "fm_modulation.h"
//#define FAST_SINE
@@ -110,8 +110,8 @@ void fm_demod_init(fm_demod_t *demod, double samplerate, double offset, double b
#endif
/* use fourth order (2 iter) filter, since it is as fast as second order (1 iter) filter */
- filter_lowpass_init(&demod->lp[0], bandwidth / 2.0, samplerate, 2);
- filter_lowpass_init(&demod->lp[1], bandwidth / 2.0, samplerate, 2);
+ iir_lowpass_init(&demod->lp[0], bandwidth / 2.0, samplerate, 2);
+ iir_lowpass_init(&demod->lp[1], bandwidth / 2.0, samplerate, 2);
#ifdef FAST_SINE
int i;
@@ -169,8 +169,8 @@ void fm_demodulate(fm_demod_t *demod, sample_t *samples, int num, float *buff)
Q[s] = i * _sin + q * _cos;
}
demod->phase = phase;
- filter_process(&demod->lp[0], I, num);
- filter_process(&demod->lp[1], Q, num);
+ iir_process(&demod->lp[0], I, num);
+ iir_process(&demod->lp[1], Q, num);
last_phase = demod->last_phase;
for (s = 0; s < num; s++) {
phase = atan2(Q[s], I[s]);
diff --git a/src/common/fm_modulation.h b/src/common/fm_modulation.h
index 194ae3f..2cd571a 100644
--- a/src/common/fm_modulation.h
+++ b/src/common/fm_modulation.h
@@ -15,7 +15,7 @@ typedef struct fm_demod {
double phase; /* current rotation phase (used to shift) */
double rot; /* rotation step per sample to shift rx frequency (used to shift) */
double last_phase; /* last phase of FM (used to demodulate) */
- filter_t lp[2]; /* filters received IQ signal */
+ iir_filter_t lp[2]; /* filters received IQ signal */
double *sin_tab; /* sine/cosine table rotation */
} fm_demod_t;
diff --git a/src/common/iir_filter.c b/src/common/iir_filter.c
new file mode 100644
index 0000000..d080728
--- /dev/null
+++ b/src/common/iir_filter.c
@@ -0,0 +1,133 @@
+/* cut-off filter (biquad) based on Nigel Redmon (www.earlevel.com)
+ *
+ * (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
+ * All Rights Reserved
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <stdlib.h>
+#include <math.h>
+#include "sample.h"
+#include "iir_filter.h"
+
+#define PI M_PI
+
+void iir_lowpass_init(iir_filter_t *filter, double frequency, int samplerate, int iterations)
+{
+ double Fc, Q, K, norm;
+
+ if (iterations > 64) {
+ fprintf(stderr, "%s failed: too many iterations, please fix!\n", __func__);
+ abort();
+ }
+
+ memset(filter, 0, sizeof(*filter));
+ filter->iter = iterations;
+ Q = pow(sqrt(0.5), 1.0 / (double)iterations); /* 0.7071 @ 1 iteration */
+ Fc = frequency / (double)samplerate;
+ K = tan(PI * Fc);
+ norm = 1 / (1 + K / Q + K * K);
+ filter->a0 = K * K * norm;
+ filter->a1 = 2 * filter->a0;
+ filter->a2 = filter->a0;
+ filter->b1 = 2 * (K * K - 1) * norm;
+ filter->b2 = (1 - K / Q + K * K) * norm;
+}
+
+void iir_highpass_init(iir_filter_t *filter, double frequency, int samplerate, int iterations)
+{
+ double Fc, Q, K, norm;
+
+ memset(filter, 0, sizeof(*filter));
+ filter->iter = iterations;
+ Q = pow(sqrt(0.5), 1.0 / (double)iterations); /* 0.7071 @ 1 iteration */
+ Fc = frequency / (double)samplerate;
+ K = tan(PI * Fc);
+ norm = 1 / (1 + K / Q + K * K);
+ filter->a0 = 1 * norm;
+ filter->a1 = -2 * filter->a0;
+ filter->a2 = filter->a0;
+ filter->b1 = 2 * (K * K - 1) * norm;
+ filter->b2 = (1 - K / Q + K * K) * norm;
+}
+
+void iir_bandpass_init(iir_filter_t *filter, double frequency, int samplerate, int iterations)
+{
+ double Fc, Q, K, norm;
+
+ memset(filter, 0, sizeof(*filter));
+ filter->iter = iterations;
+ Q = pow(sqrt(0.5), 1.0 / (double)iterations); /* 0.7071 @ 1 iteration */
+ Fc = frequency / (double)samplerate;
+ K = tan(PI * Fc);
+ norm = 1 / (1 + K / Q + K * K);
+ filter->a0 = K / Q * norm;
+ filter->a1 = 0;
+ filter->a2 = -filter->a0;
+ filter->b1 = 2 * (K * K - 1) * norm;
+ filter->b2 = (1 - K / Q + K * K) * norm;
+}
+
+void iir_notch_init(iir_filter_t *filter, double frequency, int samplerate, int iterations)
+{
+ double Fc, Q, K, norm;
+
+ memset(filter, 0, sizeof(*filter));
+ filter->iter = iterations;
+ Q = pow(sqrt(0.5), 1.0 / (double)iterations); /* 0.7071 @ 1 iteration */
+ Fc = frequency / (double)samplerate;
+ K = tan(PI * Fc);
+ norm = 1 / (1 + K / Q + K * K);
+ filter->a0 = (1 + K * K) * norm;
+ filter->a1 = 2 * (K * K - 1) * norm;
+ filter->a2 = filter->a0;
+ filter->b1 = filter->a1;
+ filter->b2 = (1 - K / Q + K * K) * norm;
+}
+
+void iir_process(iir_filter_t *filter, sample_t *samples, int length)
+{
+ double a0, a1, a2, b1, b2;
+ double *z1, *z2;
+ double in, out;
+ int iterations = filter->iter;
+ int i, j;
+
+ /* get states */
+ a0 = filter->a0;
+ a1 = filter->a1;
+ a2 = filter->a2;
+ b1 = filter->b1;
+ b2 = filter->b2;
+
+ z1 = filter->z1;
+ z2 = filter->z2;
+
+ /* process filter */
+ for (i = 0; i < length; i++) {
+ in = *samples;
+ for (j = 0; j < iterations; j++) {
+ out = in * a0 + z1[j];
+ z1[j] = in * a1 + z2[j] - b1 * out;
+ z2[j] = in * a2 - b2 * out;
+ in = out;
+ }
+ *samples++ = in;
+ }
+}
+
diff --git a/src/common/iir_filter.h b/src/common/iir_filter.h
new file mode 100644
index 0000000..9d237eb
--- /dev/null
+++ b/src/common/iir_filter.h
@@ -0,0 +1,16 @@
+#ifndef _FILTER_H
+#define _FILTER_H
+
+typedef struct iir_filter {
+ int iter;
+ double a0, a1, a2, b1, b2;
+ double z1[64], z2[64];
+} iir_filter_t;
+
+void iir_lowpass_init(iir_filter_t *filter, double frequency, int samplerate, int iterations);
+void iir_highpass_init(iir_filter_t *filter, double frequency, int samplerate, int iterations);
+void iir_bandpass_init(iir_filter_t *filter, double frequency, int samplerate, int iterations);
+void iir_notch_init(iir_filter_t *filter, double frequency, int samplerate, int iterations);
+void iir_process(iir_filter_t *filter, sample_t *samples, int length);
+
+#endif /* _FILTER_H */
diff --git a/src/common/samplerate.c b/src/common/samplerate.c
index 8187748..db6b278 100644
--- a/src/common/samplerate.c
+++ b/src/common/samplerate.c
@@ -25,7 +25,7 @@
#include "sample.h"
#include "samplerate.h"
-int init_samplerate(samplerate_t *state, double low_samplerate, double high_samplerate)
+int init_samplerate(samplerate_t *state, double low_samplerate, double high_samplerate, double filter_cutoff)
{
memset(state, 0, sizeof(*state));
state->factor = high_samplerate / low_samplerate;
@@ -34,8 +34,8 @@ int init_samplerate(samplerate_t *state, double low_samplerate, double high_samp
abort();
}
- filter_lowpass_init(&state->up.lp, 3300.0, high_samplerate, 2);
- filter_lowpass_init(&state->down.lp, 3300.0, high_samplerate, 2);
+ iir_lowpass_init(&state->up.lp, filter_cutoff, high_samplerate, 2);
+ iir_lowpass_init(&state->down.lp, filter_cutoff, high_samplerate, 2);
return 0;
}
@@ -49,7 +49,7 @@ int samplerate_downsample(samplerate_t *state, sample_t *samples, int input_num)
sample_t last_sample;
/* filter down */
- filter_process(&state->down.lp, samples, input_num);
+ iir_process(&state->down.lp, samples, input_num);
/* get last sample for interpolation */
last_sample = state->down.last_sample;
@@ -144,7 +144,7 @@ int samplerate_upsample(samplerate_t *state, sample_t *input, int input_num, sam
state->up.in_index = in_index;
/* filter up */
- filter_process(&state->up.lp, samples, output_num);
+ iir_process(&state->up.lp, samples, output_num);
if (input == output) {
/* copy samples */
diff --git a/src/common/samplerate.h b/src/common/samplerate.h
index 8c69741..4fbf680 100644
--- a/src/common/samplerate.h
+++ b/src/common/samplerate.h
@@ -1,19 +1,19 @@
-#include "filter.h"
+#include "iir_filter.h"
typedef struct samplerate {
double factor;
struct {
- filter_t lp;
+ iir_filter_t lp;
sample_t last_sample;
double in_index;
} down;
struct {
- filter_t lp;
+ iir_filter_t lp;
sample_t last_sample;
double in_index;
} up;
} samplerate_t;
-int init_samplerate(samplerate_t *state, double low_samplerate, double high_samplerate);
+int init_samplerate(samplerate_t *state, double low_samplerate, double high_samplerate, double filter_cutoff);
int samplerate_downsample(samplerate_t *state, sample_t *samples, int input_num);
int samplerate_upsample(samplerate_t *state, sample_t *input, int input_num, sample_t *output);
diff --git a/src/common/sdr.c b/src/common/sdr.c
index 4205c21..b654b4f 100644
--- a/src/common/sdr.c
+++ b/src/common/sdr.c
@@ -24,7 +24,7 @@
#include <errno.h>
#include <math.h>
#include "sample.h"
-#include "filter.h"
+#include "iir_filter.h"
#include "fm_modulation.h"
#include "sender.h"
#ifdef HAVE_UHD
diff --git a/src/common/sender.c b/src/common/sender.c
index da7822b..8137cef 100644
--- a/src/common/sender.c
+++ b/src/common/sender.c
@@ -114,7 +114,7 @@ int sender_create(sender_t *sender, int kanal, double sendefrequenz, double empf
}
}
- rc = init_samplerate(&sender->srstate, 8000.0, (double)samplerate);
+ rc = init_samplerate(&sender->srstate, 8000.0, (double)samplerate, 3300.0);
if (rc < 0) {
PDEBUG(DSENDER, DEBUG_ERROR, "Failed to init sample rate conversion!\n");
goto error;