T-Echo Card audio support initial stages - codec2 attempts

2026-06-17 16:35:03 +02:00 · 2026-05-07 05:47:18 +10:00
parent 4b734f1bac
commit 708b96e0e8
109 changed files with 87144 additions and 24 deletions
@@ -0,0 +1,103 @@
+/*---------------------------------------------------------------------------*\
+
+  FILE........: ofdm_internal.h
+  AUTHORS.....: David Rowe & Steve Sampson
+  DATE CREATED: June 2017
+
+  OFDM Internal definitions.
+
+\*---------------------------------------------------------------------------*/
+
+/*
+  Copyright (C) 2017 David Rowe
+
+  All rights reserved.
+
+  This program is free software; you can redistribute it and/or modify
+  it under the terms of the GNU Lesser General Public License version 2, as
+  published by the Free Software Foundation.  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 Lesser General Public License
+  along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef OFDM_INTERNAL_H
+#define OFDM_INTERNAL_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <complex.h>
+#include <stdbool.h>
+
+#ifndef M_PI
+#define M_PI        3.14159265358979323846f  /* math constant */
+#endif
+
+#define TAU         (2.0f * M_PI)            /* mathematical constant */
+
+#define OFDM_NC     16
+#define OFDM_TS     0.018f
+#define OFDM_RS     (1.0f / OFDM_TS)
+#define OFDM_FS     8000.0f
+#define OFDM_BPS    2
+#define OFDM_TCP    0.002f
+#define OFDM_NS     8
+#define OFDM_CENTRE 1500.0f
+
+/* To prevent C99 warning */
+
+#define OFDM_M      144
+#define OFDM_NCP    16
+
+#ifdef OLD_STYLE
+/* This will produce a warning in C99 as (int) makes these variable */
+
+#define OFDM_M      ((int)(OFDM_FS / OFDM_RS))
+#define OFDM_NCP    ((int)(OFDM_TCP * OFDM_FS))
+#endif
+
+#define OFDM_FTWINDOWWIDTH       11
+#define OFDM_BITSPERFRAME        ((OFDM_NS - 1) * (OFDM_NC * OFDM_BPS))
+#define OFDM_ROWSPERFRAME        (OFDM_BITSPERFRAME / (OFDM_NC * OFDM_BPS))
+#define OFDM_SAMPLESPERFRAME     (OFDM_NS * (OFDM_M + OFDM_NCP))
+#define OFDM_MAX_SAMPLESPERFRAME (OFDM_SAMPLESPERFRAME + (OFDM_M + OFDM_NCP)/4)
+#define OFDM_RXBUF               (3 * OFDM_SAMPLESPERFRAME + 3 * (OFDM_M + OFDM_NCP))
+
+struct OFDM {
+    float foff_est_gain;
+    float foff_est_hz;
+
+    int verbose;
+    int sample_point;
+    int timing_est;
+    int nin;
+
+    bool timing_en;
+    bool foff_est_en;
+    bool phase_est_en;
+
+    complex float pilot_samples[OFDM_M + OFDM_NCP];
+    complex float W[OFDM_NC + 2][OFDM_M];
+    complex float rxbuf[OFDM_RXBUF];
+    complex float pilots[OFDM_NC + 2];
+    float w[OFDM_NC + 2];
+    
+    /* Demodulator data */
+
+    complex float rx_sym[OFDM_NS + 3][OFDM_NC + 2];
+    complex float rx_np[OFDM_ROWSPERFRAME * OFDM_NC];
+    float rx_amp[OFDM_ROWSPERFRAME * OFDM_NC];
+    float aphase_est_pilot_log[OFDM_ROWSPERFRAME * OFDM_NC];
+};
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif