Merge branch 'dr-datac14' into dr-freedata-001

drowe67 · May 1, 2024 · d321ccf · d321ccf
2 parents 2841e6c + 7f6188c
commit d321ccf
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Showing 5 changed files with 5 additions and 5 deletions.
diff --git a/README_data.md b/README_data.md
@@ -146,7 +146,7 @@ These modes use an OFDM modem with powerful LDPC codes and are designed for send
 | DATAC3 | 500 | 321 | 126 | (2048,1024) | 3.19 | 74/100 at 0dB | Forward link data (low SNR) |
 | DATAC4 | 250 | 87 | 56 | (1472,448) | 5.17 | 90/100 at -4dB | Forward link data (low SNR) |
 | DATAC13 | 200 | 64 | 14 | (384,128) | 2.0 | 90/100 at -4dB | Reverse link ACK packets (low SNR) |
-| DATAC14 | 250 | 58 | 3 | (112,56) | 0.69 | 90/100 at -4dB | Reverse link ACK packets (low SNR) |
+| DATAC14 | 250 | 58 | 3 | (112,56) | 0.69 | 90/100 at -2dB | Reverse link ACK packets (low SNR) |
 
 Notes:
 1. 16 bits (2 bytes) per frame are reserved for a 16 bit CRC, e.g. for `datac3` we have 128 byte frames, and 128-2=126 bytes/frame of payload data.
@@ -246,7 +246,7 @@ This command line demonstrates the effect:
 ```
 Try adjusting `--clip` and `No` argument of `ch` (noise level) for different modes.  Note the SNR estimates returned from `freedv_data_raw_rx` compared to the SNR from the channel simulator `ch`. You will notice clipping also increases the RMS power and reduces the PER for a given channel noise power.  CPAPR will also reduce with clipping enabled.
 
-The following plots illustrate the SNR estimates versus actual channel SNR with and without compression (clipping).  Not that even with the uncompressed waveform there is a small offset of around 1dB, possibly due to modem implementation loss or noise in the frequency, phase, or timing estimators.
+The following plots illustrate the SNR estimates versus actual channel SNR with and without compression (clipping).  Note that even with the uncompressed waveform there is a small offset of around 1dB, possibly due to modem implementation loss or noise in the frequency, phase, or timing estimators.
 
 ![](doc/snrest_snr_ctx.png)
 ![](doc/snrest_snr_ctxc.png)

diff --git a/doc/c_tx_comp.png b/doc/c_tx_comp.png
diff --git a/doc/c_tx_comp_thruput.png b/doc/c_tx_comp_thruput.png
diff --git a/octave/ofdm_mode.m b/octave/ofdm_mode.m
@@ -144,7 +144,7 @@
     config.tx_uw(end-24+1:end) = [1 1 0 0  1 0 1 0  1 1 1 1  0 0 0 0  1 1 1 1  0 0 0 0];
     config.amp_est_mode = 1; config.EsNodB = 3;
     config.state_machine = "data"; 
-    config.amp_scale = 2.5*300E3; config.clip_gain1 = 1.2; config.clip_gain2 = 1.0;
+    config.amp_scale = 2*300E3; config.clip_gain1 = 2; config.clip_gain2 = 1;
     config.txbpf_width_Hz = 400;
   elseif strcmp(mode,"1")
     Ns=5; config.Np=10; Tcp=0; Tframe = 0.1; Ts = Tframe/Ns; Nc = 1;

diff --git a/src/ofdm_mode.c b/src/ofdm_mode.c
@@ -247,8 +247,8 @@ void ofdm_init_mode(char mode[], struct OFDM_CONFIG *config) {
     memcpy(config->tx_uw, uw, sizeof(uw));
     memcpy(&config->tx_uw[config->nuwbits - sizeof(uw)], uw, sizeof(uw));
     config->data_mode = "streaming";
-    config->amp_scale = 2.5 * 300E3;
-    config->clip_gain1 = 1.2;
+    config->amp_scale = 2.0 * 300E3;
+    config->clip_gain1 = 2.0;
     config->clip_gain2 = 1.0;
     config->rx_bpf_en = true;
   } else {