--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/cs/layer1/gtt_include/ctm/tonemod.h	Fri May 15 01:28:16 2020 +0000
@@ -0,0 +1,78 @@
+/*
+*******************************************************************************
+*
+*      COPYRIGHT (C) 2000 BY ERICSSON EUROLAB DEUTSCHLAND GmbH
+*      90411 NUERNBERG, GERMANY, Tel Int + 49 911 5217 100
+*
+*      The program(s) may be used and/or copied only with the
+*      written permission from Ericsson or in accordance
+*      with the terms and conditions stipulated in the agreement or
+*      contract under which the program(s) have been supplied.
+*
+*      Changes since October 13, 2000:
+*      - The type mod_state_t includes a new member txbits_fifo_state now.
+*
+*******************************************************************************
+*
+*      File             : tonemod.h
+*      Purpose          : header file for tonemod.c
+*
+*******************************************************************************
+*/
+
+#ifndef tonemod_h
+#define tonemod_h "$Id: $"
+
+/*
+*******************************************************************************
+*                         INCLUDE FILES
+*******************************************************************************
+*/
+
+#include <fifo.h>
+
+/*
+*******************************************************************************
+*                         DECLARATION OF PROTOTYPES
+*******************************************************************************
+*/
+
+
+/* Define a type for the state variable of the function tonemod()     */
+
+typedef struct {
+  WORD16      cntModulatedSamples;
+  WORD16      actualBits[2];
+  fifo_state_t  txbits_fifo_state;
+} mod_state_t;
+
+
+/* ---------------------------------------------------------------------- */
+/* Function init_tonemod()                                                */
+/* ***********************                                                */
+/* This function has to be executed before tonemod() can be used.         */
+/* ---------------------------------------------------------------------- */
+
+void init_tonemod(mod_state_t  *mod_state);
+
+
+/* ---------------------------------------------------------------------- */
+/* Function tonemod()                                                     */
+/* ******************                                                     */
+/* Modulator of the Cellular Text Telephone Modem.                        */
+/* The input vector bits_in must contain the bits that have to be         */
+/* transmitted. The length of bits_in must be even because always two     */
+/* bits are coded in parallel.                                            */
+/* Bits are either unipolar (i.e. {0, 1}) or bipolar (i.e. {-1, +1)}.     */
+/* The length of the output vector tones_out must be 20 times longer than */
+/* the length of bits_in, since each pair of two bits is coded within a   */
+/* frame of 40 audio samples.                                             */
+/* ---------------------------------------------------------------------- */
+
+void tonemod(WORD16    *tones_out,
+             WORD16    *bits_in,
+             WORD16     num_samples_tones_out,
+             WORD16     num_bits_in,
+             mod_state_t *mod_state);
+
+#endif