From: drowe67 <drowe67@01035d8c-6547-0410-b346-abe4f91aad63>
Date: Tue, 24 Apr 2018 07:02:49 +0000 (+0000)
Subject: adjusted ofdm levels to be the same as fdmdv - C
X-Git-Url: http://git.whiteaudio.com/gitweb/?a=commitdiff_plain;h=05cb9cfc3c45b8d39e449de075105cb80302d39a;p=freetel-svn-tracking.git
adjusted ofdm levels to be the same as fdmdv - C
git-svn-id: https://svn.code.sf.net/p/freetel/code@3524 01035d8c-6547-0410-b346-abe4f91aad63
---
diff --git a/codec2-dev/src/codec2_ofdm.h b/codec2-dev/src/codec2_ofdm.h
index d2a4b5a4..3fc69833 100644
--- a/codec2-dev/src/codec2_ofdm.h
+++ b/codec2-dev/src/codec2_ofdm.h
@@ -41,6 +41,8 @@ extern "C" {
/* Defines */
+#define OFDM_AMP_SCALE (2E5*1.1491/1.06) /* use to scale to 16 bit short */
+
struct OFDM;
/* Default configuration for '700D' mode */
diff --git a/codec2-dev/src/freedv_api.c b/codec2-dev/src/freedv_api.c
index eb21a47f..2333abc2 100644
--- a/codec2-dev/src/freedv_api.c
+++ b/codec2-dev/src/freedv_api.c
@@ -68,9 +68,11 @@
* Changed all input and output sample rates to 8000 sps. Rates for FREEDV_MODE_700 and 700B were 7500.
*/
-#define NORM_PWR_COHPSK 1.74 /* experimentally derived fudge factor to normalise power for cohpsk modes */
-#define NORM_PWR_FSK 0.193 /* experimentally derived fudge factor to normalise power for fsk modes */
-#define NORM_PWR_OFDM 10.00 /* todo: experimentally derived fudge factor to normalise power for OFDM modes */
+/* experimentally derived fudge factors to normalise power across modes */
+
+#define NORM_PWR_COHPSK 1.74
+#define NORM_PWR_FSK 0.193
+#define NORM_PWR_OFDM 1.00
/* OFDM payload data test frame for 700D */
@@ -927,7 +929,7 @@ static void freedv_comptx_700d(struct freedv *f, COMP mod_out[]) {
for(i=0; i<f->n_nat_modem_samples; i++) {
asam.real = crealf(tx_sams[i]);
asam.imag = cimagf(tx_sams[i]);
- mod_out[i] = fcmult(FDMDV_SCALE*NORM_PWR_OFDM, asam);
+ mod_out[i] = fcmult(OFDM_AMP_SCALE*NORM_PWR_OFDM, asam);
}
assert(f->clip == 0); /* todo: support clipping, requires some simulations and testing */
@@ -1110,10 +1112,16 @@ int freedv_rx(struct freedv *f, short speech_out[], short demod_in[]) {
if ( (f->mode == FREEDV_MODE_1600) || (f->mode == FREEDV_MODE_700) || (f->mode == FREEDV_MODE_700B) ||
(f->mode == FREEDV_MODE_700C) || (f->mode == FREEDV_MODE_700D)) {
+
+ float gain = 1.0;
+ if (f->mode == FREEDV_MODE_700D) {
+ gain = 2.0; /* keep levels the same as Octave simulations and C unit tests for real signals */
+ }
+
/* FDM RX happens with complex samps, so do that */
COMP rx_fdm[f->n_max_modem_samples];
for(i=0; i<nin; i++) {
- rx_fdm[i].real = (float)demod_in[i];
+ rx_fdm[i].real = gain*(float)demod_in[i];
rx_fdm[i].imag = 0.0;
}
return freedv_comprx(f, speech_out, rx_fdm);
@@ -1556,16 +1564,14 @@ static int freedv_comprx_700(struct freedv *f, COMP demod_in_8kHz[], int *valid)
TODO:
[X] in testframe mode count coded and uncoded errors
[X] freedv getter for modem and interleaver sync
+ [X] rms level the same as fdmdv
[ ] way to stay in sync and not resync automatically
[ ] SNR est, maybe from pilots, cohpsk have an example?
[ ] error pattern support?
[ ] work out how to handle return of multiple interleaved frames over time
[ ] deal with out of sync returning nin samples, listening to analog audio when out of sync
- [ ] level issues
*/
-#define ASCALE (2E5*1.1491/2.0) /* scale from shorts back to floats */
-
static int freedv_comprx_700d(struct freedv *f, COMP demod_in_8kHz[], int *valid) {
int bits_per_codec_frame, bytes_per_codec_frame;
int i, j, bit, byte, nout, k;
@@ -1597,8 +1603,8 @@ static int freedv_comprx_700d(struct freedv *f, COMP demod_in_8kHz[], int *valid
COMP rxbuf_in[f->nin];
for(i=0; i<f->nin; i++) {
- rxbuf_in[i].real = demod_in_8kHz[i].real/ASCALE;
- rxbuf_in[i].imag = demod_in_8kHz[i].imag/ASCALE;
+ rxbuf_in[i].real = demod_in_8kHz[i].real/OFDM_AMP_SCALE;
+ rxbuf_in[i].imag = demod_in_8kHz[i].imag/OFDM_AMP_SCALE;
}
/* echo samples back out as default (say if sync not found) */
@@ -1607,7 +1613,7 @@ static int freedv_comprx_700d(struct freedv *f, COMP demod_in_8kHz[], int *valid
/* TODO estimate this properly from signal */
- float EsNo = 10.0;
+ float EsNo = 3.0;
/* looking for modem sync */
@@ -1621,7 +1627,7 @@ static int freedv_comprx_700d(struct freedv *f, COMP demod_in_8kHz[], int *valid
ofdm_demod(ofdm, rx_bits, rxbuf_in);
assert((OFDM_NUWBITS+OFDM_NTXTBITS+coded_bits_per_frame) == OFDM_BITSPERFRAME);
-
+t
/* now we need to buffer for de-interleaving -------------------------------------*/
/* shift interleaved symbol buffers to make room for new symbols */
diff --git a/codec2-dev/src/ofdm_demod.c b/codec2-dev/src/ofdm_demod.c
index 3c00cad0..199e6f71 100644
--- a/codec2-dev/src/ofdm_demod.c
+++ b/codec2-dev/src/ofdm_demod.c
@@ -46,7 +46,6 @@
#include "gp_interleaver.h"
#include "interldpc.h"
-#define ASCALE (2E5*1.1491/2.0) /* scale from shorts back to floats */
#define NFRAMES 100 /* just log the first 100 frames */
#define NDISCARD 20 /* BER2measure disctrds first 20 frames */
@@ -198,7 +197,7 @@ int main(int argc, char *argv[])
/* scale and demod */
for(i=0; i<nin_frame; i++) {
- rxbuf_in[i].real = (float)rx_scaled[i]/ASCALE;
+ rxbuf_in[i].real = (float)rx_scaled[i]/(OFDM_AMP_SCALE/2);
rxbuf_in[i].imag = 0.0;
}
diff --git a/codec2-dev/src/ofdm_mod.c b/codec2-dev/src/ofdm_mod.c
index 504c7fca..582a406a 100644
--- a/codec2-dev/src/ofdm_mod.c
+++ b/codec2-dev/src/ofdm_mod.c
@@ -39,8 +39,6 @@
#include "interldpc.h"
#include "gp_interleaver.h"
-#define ASCALE (2E5*1.1491)
-
extern int payload_data_bits[];
extern int test_bits_ofdm[];
@@ -161,7 +159,7 @@ int main(int argc, char *argv[])
for (j=0; j<interleave_frames; j++) {
for(i=0; i<Nsamperframe; i++) {
- tx_scaled[i] = ASCALE * crealf(tx_sams[j*Nsamperframe+i]);
+ tx_scaled[i] = OFDM_AMP_SCALE * crealf(tx_sams[j*Nsamperframe+i]);
}
fwrite(tx_scaled, sizeof(short), Nsamperframe, fout);
frames++;
@@ -185,7 +183,7 @@ int main(int argc, char *argv[])
/* scale and save to disk as shorts */
for(i=0; i<Nsamperframe; i++)
- tx_scaled[i] = ASCALE * tx_sams[i].real;
+ tx_scaled[i] = OFDM_AMP_SCALE * tx_sams[i].real;
fwrite(tx_scaled, sizeof(short), Nsamperframe, fout);
frames++;