From 30754b17df67a808e7c960d4f3c94a6b05557a17 Mon Sep 17 00:00:00 2001
From: Johnathan Corgan <jcorgan@corganenterprises.com>
Date: Mon, 18 Jul 2011 06:28:05 -0700
Subject: gr-vocoder: reimplemented gr-gsm-fr-vocoder in gr-vocoder
---
gr-vocoder/lib/gsm/code.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 100 insertions(+)
create mode 100644 gr-vocoder/lib/gsm/code.c
(limited to 'gr-vocoder/lib/gsm/code.c')
diff --git a/gr-vocoder/lib/gsm/code.c b/gr-vocoder/lib/gsm/code.c
new file mode 100644
index 0000000000..19af507b72
--- /dev/null
+++ b/gr-vocoder/lib/gsm/code.c
@@ -0,0 +1,100 @@
+/*
+ * Copyright 1992 by Jutta Degener and Carsten Bormann, Technische
+ * Universitaet Berlin. See the accompanying file "COPYRIGHT" for
+ * details. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE.
+ */
+
+/* $Header$ */
+
+#include "config.h"
+
+
+#ifdef HAS_STDLIB_H
+#include <stdlib.h>
+#else
+# include "proto.h"
+ extern char * memcpy P((char *, char *, int));
+#endif
+
+#include "private.h"
+#include "gsm.h"
+#include "proto.h"
+#include <string.h>
+
+/*
+ * 4.2 FIXED POINT IMPLEMENTATION OF THE RPE-LTP CODER
+ */
+
+void Gsm_Coder P8((S,s,LARc,Nc,bc,Mc,xmaxc,xMc),
+
+ struct gsm_state * S,
+
+ word * s, /* [0..159] samples IN */
+
+/*
+ * The RPE-LTD coder works on a frame by frame basis. The length of
+ * the frame is equal to 160 samples. Some computations are done
+ * once per frame to produce at the output of the coder the
+ * LARc[1..8] parameters which are the coded LAR coefficients and
+ * also to realize the inverse filtering operation for the entire
+ * frame (160 samples of signal d[0..159]). These parts produce at
+ * the output of the coder:
+ */
+
+ word * LARc, /* [0..7] LAR coefficients OUT */
+
+/*
+ * Procedure 4.2.11 to 4.2.18 are to be executed four times per
+ * frame. That means once for each sub-segment RPE-LTP analysis of
+ * 40 samples. These parts produce at the output of the coder:
+ */
+
+ word * Nc, /* [0..3] LTP lag OUT */
+ word * bc, /* [0..3] coded LTP gain OUT */
+ word * Mc, /* [0..3] RPE grid selection OUT */
+ word * xmaxc,/* [0..3] Coded maximum amplitude OUT */
+ word * xMc /* [13*4] normalized RPE samples OUT */
+)
+{
+ int k;
+ word * dp = S->dp0 + 120; /* [ -120...-1 ] */
+ word * dpp = dp; /* [ 0...39 ] */
+
+ static word e[50];
+
+ word so[160];
+
+ Gsm_Preprocess (S, s, so);
+ Gsm_LPC_Analysis (S, so, LARc);
+ Gsm_Short_Term_Analysis_Filter (S, LARc, so);
+
+ for (k = 0; k <= 3; k++, xMc += 13) {
+
+ Gsm_Long_Term_Predictor ( S,
+ so+k*40, /* d [0..39] IN */
+ dp, /* dp [-120..-1] IN */
+ e + 5, /* e [0..39] OUT */
+ dpp, /* dpp [0..39] OUT */
+ Nc++,
+ bc++);
+
+ Gsm_RPE_Encoding ( S,
+ e + 5, /* e ][0..39][ IN/OUT */
+ xmaxc++, Mc++, xMc );
+ /*
+ * Gsm_Update_of_reconstructed_short_time_residual_signal
+ * ( dpp, e + 5, dp );
+ */
+
+ { register int i;
+ register longword ltmp;
+ for (i = 0; i <= 39; i++)
+ dp[ i ] = GSM_ADD( e[5 + i], dpp[i] );
+ }
+ dp += 40;
+ dpp += 40;
+
+ }
+ (void)memcpy( (char *)S->dp0, (char *)(S->dp0 + 160),
+ 120 * sizeof(*S->dp0) );
+}
--
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