qtsoundmodem/ax25_mod.c

/*
Copyright (C) 2019-2020 Andrei Kopanchuk UZ7HO

This file is part of QtSoundModem

QtSoundModem is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

QtSoundModem 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 General Public License
along with QtSoundModem.  If not, see http://www.gnu.org/licenses

*/

// UZ7HO Soundmodem Port by John Wiseman G8BPQ


#include "UZ7HOStuff.h"

// I assume this modulates (and sends?} frames

void InitBuffers();
void EncodeRS(Byte * xData, Byte * xEncoded);
void scrambler(UCHAR * in_buf, int Len);
void fx25_encode_rs(Byte * data, Byte *parity, int pad, int rs_size);
int fx25_decode_rs(Byte * data, int * eras_pos, int no_eras, int pad, int rs_size);
int il2p_get_new_bit_tail(UCHAR snd_ch, UCHAR bit);
int il2p_get_new_bit(int snd_ch, Byte bit);
int ARDOPSendToCard(int Chan, int Len);
void Flush();
void SampleSink(int LR, short Sample);

int RSEncode(UCHAR * bytToRS, UCHAR * RSBytes, int DataLen, int RSLen);

//unit ax25_mod;

//interface

//uses sysutils,classes,math

extern int SampleNo;

extern BOOL KISSServ;

extern TStringList KISS_acked[];
extern TStringList KISS_iacked[];

extern UCHAR modem_mode[];

#define sbc 175

extern single  ch_offset[4];
int Continuation[4] = { 0, 0, 0, 0 };	// Sending 2nd or more packet of burst

#define COS45 0.70710676908493f

#define TX_SILENCE 0
#define TX_DELAY 1
#define TX_TAIL 2
#define TX_NO_DATA 3
#define TX_FRAME 4
#define TX_WAIT_BPF 5


#define TX_BIT0 0
#define TX_BIT1 1
#define FRAME_EMPTY 0
#define FRAME_FULL 1
#define FRAME_NO_FRAME 2
#define FRAME_NEW_FRAME 3
#define BYTE_EMPTY 0
#define BYTE_FULL 1


UCHAR gray_8PSK[8] = {7,0,6,5,2,1,3,4};		// ?? was 1::8

UCHAR gray_PI4QPSK[4] = {3,1,5,7};


float audio_buf[5][32768];  // [1..4,0..32767]
float tx_src_BPF_buf[5][32768];
float tx_BPF_buf[5][32768];
float tx_prev_BPF_buf[5][32768];
float tx_BPF_core[5][32768];

long tx_delay_cnt[5] = {0};		//			 : array[1..4] of longword=(0,0,0,0};
long tx_tail_cnt[5] = {0};

int tx_hitoneraisedb[5] = {0};		//   : array[1..4] of integer=(0,0,0,0};
float tx_hitoneraise[5] = {0};		//     : array[1..4] of single=(0,0,0,0};
float tx_freq[5] = { 1000, 1000, 1000, 1000, 1000};			//			     : array[1..4] of single=(1000,1000,1000,1000};
float tx_shift[5] = { 200, 200, 200, 200, 200};				  //   : array[1..4] of single=(200,200,200,200};
float tx_bit_mod[5] = {1, 1, 1, 1, 1};		//			   : array[1..4] of single=(1,1,1,1};
float tx_osc[5] = {0};		//						 : array[1..4] of single=(0,0,0,0};
float tx_bit_osc[5] = {0};		//			   : array[1..4] of single=(0,0,0,0};
unsigned short txbpf[5] = { 400, 400, 400, 400, 400};		//						  : array[1..4] of word=(400,400,400,400};
unsigned short  tx_BPF_tap[5] = { 256, 256, 256, 256, 256};		//			   : array[1..4] of word=(256,256,256,256};
unsigned short  tx_baudrate[5] = { 300, 300, 300, 300, 300 };		//			  : array[1..4] of word=(300,300,300,300};
unsigned short  tx_bitrate[5] = { 300, 300, 300, 300, 300 };		//			  : array[1..4] of word=(300,300,300,300};
unsigned short  tx_BPF_timer[5] = {0};		//			 : array[1..4] of word=(0,0,0,0};
UCHAR tx_pol[5] = {0};		//						 : array[1..4] of byte=(0,0,0,0};
UCHAR tx_last_pol[5] = {0};		//			  : array[1..4] of byte=(0,0,0,0};
UCHAR tx_last_diddle[5] = {0};		//     : array[1..4] of byte=(0,0,0,0};
UCHAR tx_flag_cnt[5] = {0};		//			  : array[1..4] of byte=(0,0,0,0};
UCHAR tx_frame_status[5] = {0};		//    : array[1..4] of byte=(0,0,0,0};
UCHAR tx_byte_status[5] = {0};		//     : array[1..4] of byte=(0,0,0,0};
UCHAR tx_status[5] = {0};		//			     : array[1..4] of byte=(0,0,0,0};
UCHAR tx_bit_stuff_cnt[5] = {0};		//    : array[1..4] of byte=(0,0,0,0};
UCHAR tx_bit_cnt[5] = {0};		//			    : array[1..4] of byte=(0,0,0,0};
UCHAR tx_last_bit[5] = {0};		//			   : array[1..4] of byte=(0,0,0,0};
UCHAR tx_bit_stream[5] = {0};		//			 : array[1..4] of byte=(0,0,0,0};

UCHAR tx_8PSK[5] = {0};		//						 : array[1..4] of byte=(0,0,0,0};
UCHAR tx_QPSK[5] = {0};		//						 : array[1..4] of byte=(0,0,0,0};

float tx_I_mod[5] = {1, 1, 1, 1, 1};		//						: array[1..4] of single=(1,1,1,1};
float tx_Q_mod[5] = {1, 1, 1, 1, 1};		//						: array[1..4] of single=(1,1,1,1};
float tx_QPSK_avg_I[5] = {0};		//			 : array[1..4] of single=(0,0,0,0};
float tx_QPSK_avg_Q[5] = {0};		//			 : array[1..4] of single=(0,0,0,0};
float tx_QPSK_df_I[5] = {0};		//			  : array[1..4] of single=(0,0,0,0};
float tx_QPSK_df_Q [5] = {0};		//			 : array[1..4] of single=(0,0,0,0};
float tx_QPSK_I[5] = {0};		//			     : array[1..4] of single=(0,0,0,0};
float tx_QPSK_Q[5] = {0};		//			     : array[1..4] of single=(0,0,0,0};
float tx_QPSK_old_I[5] = {0};		//			 : array[1..4] of single=(0,0,0,0};
float tx_QPSK_old_Q[5] = {0};		//			 : array[1..4] of single=(0,0,0,0};
float tx_8PSK_avg_I[5] = {0};		//			 : array[1..4] of single=(0,0,0,0};
float tx_8PSK_avg_Q[5] = {0};		//			 : array[1..4] of single=(0,0,0,0};
float tx_8PSK_df_I[5] = {0};		//			  : array[1..4] of single=(0,0,0,0};
float tx_8PSK_df_Q[5] = {0};		//			  : array[1..4] of single=(0,0,0,0};
float tx_8PSK_I[5] = {0};		//			     : array[1..4] of single=(0,0,0,0};
float tx_8PSK_Q[5] = {0};		//			     : array[1..4] of single=(0,0,0,0};
float tx_8PSK_old_I[5] = {0};		//			 : array[1..4] of single=(0,0,0,0};
float tx_8PSK_old_Q[5] = {0};		//			 : array[1..4] of single=(0,0,0,0};

float tx_osc1[5] = {0};		//						 : array[1..4] of single=(0,0,0,0};
float tx_osc2[5] = {0};		//						 : array[1..4] of single=(0,0,0,0};
float tx_osc3[5] = {0};		//						 : array[1..4] of single=(0,0,0,0};
float tx_osc4[5] = {0};		//						 : array[1..4] of single=(0,0,0,0};
short tx_inv1[5] = {1, 1, 1, 1, 1};		//						: array[1..4] of shortint=(1,1,1,1};
short tx_inv2[5] = {1, 1, 1, 1, 1};		//						: array[1..4] of shortint=(1,1,1,1};
short tx_inv3[5] = {1, 1, 1, 1, 1};		//						: array[1..4] of shortint=(1,1,1,1};
short tx_inv4[5] = {1, 1, 1, 1, 1};		//						: array[1..4] of shortint=(1,1,1,1};
short tx_old_inv1[5] = {1, 1, 1, 1, 1};		//			  : array[1..4] of shortint=(1,1,1,1};
short tx_old_inv2[5] = {1, 1, 1, 1, 1};		//			  : array[1..4] of shortint=(1,1,1,1};
short tx_old_inv3[5] = {1, 1, 1, 1, 1};		//			  : array[1..4] of shortint=(1,1,1,1};
short tx_old_inv4[5] = {1, 1, 1, 1, 1};		//			  : array[1..4] of shortint=(1,1,1,1};
float tx_bit1_mod[5] = {1, 1, 1, 1, 1};		//			  : array[1..4] of single=(1,1,1,1};
float tx_bit2_mod[5] = {1, 1, 1, 1, 1};		//			  : array[1..4] of single=(1,1,1,1};
float tx_bit3_mod[5] = {1, 1, 1, 1, 1};		//			  : array[1..4] of single=(1,1,1,1};
float tx_bit4_mod[5] = {1, 1, 1, 1, 1};		//			  : array[1..4] of single=(1,1,1,1};
UINT tx_viterbi[5] = {0};		//			     : array[1..4] of word=(0,0,0,0};
UCHAR tx_intv_tbl[5][4];		//			  : array[1..4,0..3] of byte;

short tx_inv[5] = {1, 1, 1, 1, 1};		//						    : array[1..4] of shortint=(1,1,1,1};
BOOL tx_change_phase[5] = {0};		//    : array[1..4] of boolean=(FALSE,FALSE,FALSE,FALSE};
BOOL tx_bs_bit[5] = {0};		//			    : array[1..4] of boolean=(FALSE,FALSE,FALSE,FALSE};

string * tx_data[5] = {0};		//						: array[1..4] of string=('','','',''};
int tx_data_len[5] = {0};

int tx_fx25_size[4] = { 0, 0, 0, 0 };
int tx_fx25_size_cnt[4] = { 0, 0, 0, 0 };
int tx_fx25_mode[4] = { 0, 0, 0, 0 };


//  uses sm_main,ax25,ax25_agw,ax25_demod,rsunit;

UCHAR tx_nrzi(UCHAR snd_ch, UCHAR bit)
{
//	Debugprintf("Before NRZI %d", bit);

	if (bit == TX_BIT0)
	{
		// Zero so switch bit

		tx_last_bit[snd_ch] ^= 1;
	}
	return tx_last_bit[snd_ch];	
}

BOOL tx_bit_stuffing(UCHAR snd_ch, UCHAR bit)
{					 
 // result = FALSE;
 // if bit=TX_BIT1 then inc(tx_bit_stuff_cnt[snd_ch]};
 // if bit=TX_BIT0 then tx_bit_stuff_cnt[snd_ch] = 0;
 // if tx_bit_stuff_cnt[snd_ch]=5 then begin tx_bit_stuff_cnt[snd_ch] = 0; result = TRUE; end;
//end;

	if (bit == TX_BIT1)
		tx_bit_stuff_cnt[snd_ch]++;

	if (bit == TX_BIT0)
		tx_bit_stuff_cnt[snd_ch] = 0;

	if (tx_bit_stuff_cnt[snd_ch] == 5)
	{
		tx_bit_stuff_cnt[snd_ch] = 0;
		return TRUE;
	}

	return FALSE;
}




void interleave(char *s, int len)
{
//	var
 // data: string;
 // i,k,len: word;
 // nr_blocks: word;
//begin{
//  data = '';
 // len = length(s};
 // if len>0 then nr_blocks = ((len-1} div 16}+1 else nr_blocks = 1;
 // for i = 1 to 16 do
 //   for k = 0 to nr_blocks-1 do
  //   if (i+k*16}<=len then data = data+s[i+k*16];
 // result = data;
//end;

	char data[1024];

	UINT i,k;
	UINT nr_blocks;
	int n = 0;

	if (len > 0)
		nr_blocks = ((len - 1) / 16) + 1;
	else
		nr_blocks = 1;

	for (i = 0; i < 16; i++)
	{
		for (k = 0; k < nr_blocks; k++)
		{
			if ((i + k * 16) <= len)
				data[n++] = s[i + k * 16];
		}
	}

	memcpy(s, data, len);
}

//procedure get_new_frame(snd_ch: byte; var frame_stream: TStringList};
//var
//  header,line,temp: string;
//  len,i,size: word;
 // crc: word;
//begin

void get_new_frame(UCHAR snd_ch, TStringList * frame_stream)
{
	UCHAR header[256];
	UCHAR line[1024];

	int LineLen;

	string ** Items;

	string * myTemp;

	UCHAR temp[1024];

	UINT len, i, size;
	UINT crc;

	tx_bs_bit[snd_ch] = FALSE;
	tx_bit_cnt[snd_ch] = 0;
	tx_flag_cnt[snd_ch] = 0;
	tx_bit_stuff_cnt[snd_ch] = 0;
	tx_bit_stream[snd_ch] = FRAME_FLAG;
	tx_frame_status[snd_ch] = FRAME_NEW_FRAME;
	tx_byte_status[snd_ch] = BYTE_EMPTY;

	if (frame_stream->Count == 0)
	{
		tx_frame_status[snd_ch] = FRAME_NO_FRAME;
		return;
	}

	// We now pass control byte and ack bytes on front and pointer to socket on end if ackmode

	myTemp = Strings(frame_stream, 0);			// get message

	if ((myTemp->Data[0] & 0x0f) == 12)			// ACKMODE
	{
		// Save copy then copy data up 3 bytes

		Add(&KISS_acked[snd_ch], duplicateString(myTemp));

		mydelete(myTemp, 0, 3);
		myTemp->Length -= sizeof(void *);
	}
	else
	{
		// Just remove control 

		mydelete(myTemp, 0, 1);
	}

	tx_data[snd_ch] = duplicateString(myTemp);		// so can free original below

	Delete(frame_stream, 0);			// This will invalidate temp

	AGW_AX25_frame_analiz(snd_ch, FALSE, tx_data[snd_ch]);

	put_frame(snd_ch, tx_data[snd_ch], "", TRUE, FALSE);

	if (tx_data[snd_ch]->Length == 0 || modem_mode[snd_ch] != MODE_MPSK)
		return;

	// Reformat MPSK Data

	//Take data 8 bytes at a time and add 8 bytes of RS data

	LineLen = 0;

	while (tx_data[snd_ch]->Length > 0)
	{
		size = tx_data[snd_ch]->Length;

		if (size > 8)
			size = 8;

		memcpy(temp, tx_data[snd_ch]->Data, size);

		// Delete the chars from tx_data

		mydelete(tx_data[snd_ch], 0, 8);

		memset(xData, 0, sizeof(xData));
		memset(xEncoded, 0, sizeof(xEncoded));

		memcpy(xData, temp, size);

		InitBuffers();
		EncodeRS(xData, xEncoded);			// This puts the 8 RS bytes in xEncoded

		memcpy(&line[LineLen], xData, size);
		memcpy(&line[LineLen + size], xEncoded, MaxErrors * 2);

		LineLen += size + (MaxErrors * 2);
	}




	len = LineLen;

	interleave(line, LineLen);
	scrambler(line, LineLen);

	header[0] = 0x7e;
	header[1] = 0x7e;
	header[2] = len >> 8;
	header[3] = len;

	crc = get_fcs(header, 4);

	header[4] = crc >> 8;
	header[5] = crc;

	memset(xData, 0, sizeof(xData));
	memset(xEncoded, 0, sizeof(xEncoded));
	memmove(xData, header, 6);


	//		RSEncode(xData, xEncoded, 6 + (MaxErrors * 2), MaxErrors * 2);

	InitBuffers();
	EncodeRS(xData, xEncoded);

	fx25_encode_rs(xData, xEncoded, 0, 8);


	// We should now have RS Encoded Header in xEncoded;

	// I think we send encoded header then line

	tx_data[snd_ch]->Length = 0;

	stringAdd(tx_data[snd_ch], xData, 6);
	stringAdd(tx_data[snd_ch], xEncoded, MaxErrors * 2);
	stringAdd(tx_data[snd_ch], line, LineLen);

	// For testing, descramble and de-interleve

	scrambler(line, LineLen); // should look like interleaved
	{
		Byte unscrambled[1024];
		int count, len;
		int origlen;

		len = LineLen;
		count = (len + 15) / 16;

		int j1, j2, j3, i, j;

		j3 = 0;

		for (j1 = 0; j1 < 16; j1++)
		{
			// Each char in block

			for (j2 = 0; j2 < count; j2++)
			{
				// Blocks

				unscrambled[j2 * 16 + j1] = line[j3];
				j3++;
			}
		}

		// Now remove RS (will check later)

		i = 0;
		j = 0;

		while (j < len)
		{
			Byte line1[256];
			int nErr, eras_pos = 0;
			Byte rs_block[256];

			memcpy(line1, &unscrambled[j], 16);

			memset(xEncoded, 0, sizeof(xEncoded));
			memset(xDecoded, 0, sizeof(xDecoded));

			memcpy(xEncoded, &unscrambled[j], 16);

//			nErr = DecodeRS(xEncoded, xDecoded);

			memset(rs_block, 0, 255);
			memcpy(rs_block, &unscrambled[j], 8);
			memcpy(&rs_block[255 - 8], &unscrambled[j+8], 8);

			nErr = fx25_decode_rs(rs_block, &eras_pos, 0, 0, 8);


//			line1 = '';
//			for j1 = MaxErrors * 2 to size - 1 do line1 = line1 + chr(xDecoded[j1]);


			memcpy(&unscrambled[i], &unscrambled[j], 8);
			i += 8;
			j += 16;
		}

		j3 = j3;

	}

}
  


int get_new_bit(Byte snd_ch, Byte bit)
{
	unsigned short len;
	string * s;

	if (tx_frame_status[snd_ch] == FRAME_FULL)
	{
		if (tx_byte_status[snd_ch] == BYTE_EMPTY)
		{
			len = tx_data[snd_ch]->Length;

			if (len > 0)
			{
				s = tx_data[snd_ch];
				tx_bit_stream[snd_ch] = (s->Data[0]);
				tx_frame_status[snd_ch] = FRAME_FULL;
				tx_byte_status[snd_ch] = BYTE_FULL;
				tx_bit_cnt[snd_ch] = 0;
				mydelete(tx_data[snd_ch], 0, 1);
			}

			else tx_frame_status[snd_ch] = FRAME_EMPTY;
		}

		if (tx_byte_status[snd_ch] == BYTE_FULL)
			bit = tx_bit_stream[snd_ch] & TX_BIT1;

		if (modem_mode[snd_ch] == MODE_MPSK)
		{
			tx_bit_cnt[snd_ch]++;
			tx_bit_stream[snd_ch] = tx_bit_stream[snd_ch] >> 1;
			if (tx_bit_cnt[snd_ch] >= 8)
				tx_byte_status[snd_ch] = BYTE_EMPTY;

		}
		else
		{
			if (tx_bs_bit[snd_ch])
				bit = TX_BIT0;

			tx_bs_bit[snd_ch] = tx_bit_stuffing(snd_ch, bit);

			if (!tx_bs_bit[snd_ch])
			{
				tx_bit_cnt[snd_ch]++;
				tx_bit_stream[snd_ch] >>= 1;
				if (tx_bit_cnt[snd_ch] >= 8 && !tx_bs_bit[snd_ch])
					tx_byte_status[snd_ch] = BYTE_EMPTY;
			}
		}
	}

	if (tx_frame_status[snd_ch] == FRAME_EMPTY)
		get_new_frame(snd_ch, &all_frame_buf[snd_ch]);

	if ((tx_frame_status[snd_ch] == FRAME_NEW_FRAME) || (tx_frame_status[snd_ch] == FRAME_NO_FRAME))
	{
		bit = tx_bit_stream[snd_ch] & TX_BIT1;
		tx_flag_cnt[snd_ch]++;
		tx_bit_stream[snd_ch] >>= 1;

		if (tx_flag_cnt[snd_ch] == 8)
		{
			switch (tx_frame_status[snd_ch])
			{
			case FRAME_NEW_FRAME:

				tx_frame_status[snd_ch] = FRAME_FULL;
				break;

			case FRAME_NO_FRAME:

				tx_tail_cnt[snd_ch] = 0;
				tx_frame_status[snd_ch] = FRAME_EMPTY;
				tx_status[snd_ch] = TX_TAIL;

				break;
			}
		}
	}
	return bit;
}

////// FX.25 //////


void bit_to_fx25(Byte * tx_byte,  Byte * bit_cnt, Byte bit, string * data, int * data_cnt)
{
	*tx_byte = (*tx_byte >> 1) | (bit << 7);
	(*bit_cnt)++;

	if (*bit_cnt == 8)
	{
		stringAdd(data, tx_byte, 1);
		*bit_cnt = 0;
	}
	(*data_cnt)++;
}

string * fill_fx25_data(int snd_ch, string * data)
{
#define nr_tags 5

	string * result;

	Byte rs_roots[nr_tags + 1] = { 16, 32, 64, 32, 16, 16 };
	word rs_payload[nr_tags + 1] = { 1912, 1784, 1528, 1024, 512, 256 }; // 239, 233, 191, 128, 64, 32

	unsigned long long rs_tag[nr_tags + 1] =
	{
		0xB74DB7DF8A532F3E,			// 255 / 16 (239)
		0x6E260B1AC5835FAE,			// 255 / 32 (223)
		0x3ADB0C13DEAE2836,			// 255 / 64 (191)
		0xFF94DC634F1CFF4E,			// 160 / 32 (128)
		0xC7DC0508F3D9B09E,			// 80 / 16	(64)	
		0x8F056EB4369660EE 		// 48 / 16	(32)
	};

//	0x26FF60A600CC8FDE) 144; = 16;
//	0x1EB7B9CDBC09C00E) 96; 32;
//  0xDBF869BD2DBB1776) 64;= 32;
//	0xAB69DB6A543188D6) 192; = 64;
//	0x4A4ABEC4A724B796) 128; = 64;

	string * ax25_data = newString();

	int i, ax25_size;
	Byte a, bit, bit_cnt, bit_cnt1, bs, tx_byte;
	Byte rs_id;
	Byte rs_block[256], parity[256];

	ax25_size = 0;
	bs = 0;
	tx_byte = 0;
	bit_cnt = 0;

	// Load start flag
	a = FRAME_FLAG;

	for (i = 0; i < 8; i++)
	{
		bit = a & 1;
		a = a >> 1;
		bit_to_fx25(&tx_byte, &bit_cnt, bit, ax25_data, &ax25_size);
	}

	// Load body
	for (i = 0; i < data->Length; i++)
	{
		bit_cnt1 = 0;
		a = data->Data[i];
		do
		{
			if (bs == 5)
			{
				bit = TX_BIT0;
				bs = 0;
			}
			else
			{
				bit = a & 1;
				a = a >> 1;
				bit_cnt1++;

				if (bit == TX_BIT1)
					bs++;
				else
					bs = 0;
			}

			bit_to_fx25(&tx_byte, &bit_cnt, bit, ax25_data, &ax25_size);

		} while (bit_cnt1 != 8 || bs == 5);
	}

	// Load close flag

	a = FRAME_FLAG;

	for (i = 0; i < 8; i++)
	{
		bit = a & 1;
		a = a >> 1;
		bit_to_fx25(&tx_byte, &bit_cnt, bit, ax25_data, &ax25_size);
	}

	a = FRAME_FLAG;

	// if too short or too long 

	if (ax25_size < 168 || ax25_size > 1912)	// < 21 or > 239
	{
		// Send as normal ax25 packet

		if (bit_cnt > 0)
		{
			do
			{
				tx_byte = tx_byte >> 1;
				bit_cnt++;
				if (bit_cnt == 8)
					stringAdd(ax25_data, &tx_byte, 1);
			} while (bit_cnt < 8);
		}
		tx_fx25_size[snd_ch] = ax25_size;
		return ax25_data;
	}

	// Send as FX25 Message

	// find RS block size

	rs_id = 0;

	for (i = 0; i <= nr_tags; i++)
		if (ax25_size <= rs_payload[i])
			rs_id = i;

	// Padding to block size

	while (ax25_size != rs_payload[rs_id])
	{
		bit = a & 1;
		a = (a >> 1) | (bit << 7);
		bit_to_fx25(&tx_byte, &bit_cnt, bit, ax25_data, &ax25_size);
	}

	memset(rs_block, 0, 255);
	move(&ax25_data->Data[0], &rs_block[0], ax25_data->Length);

	fx25_encode_rs(rs_block, parity, 0, rs_roots[rs_id]);

	result = newString();

	stringAdd(result, (Byte *)&rs_tag[rs_id], 8);
	stringAdd(result, ax25_data->Data, ax25_data->Length);
	stringAdd(result, parity, rs_roots[rs_id]);

	tx_fx25_size[snd_ch] = result->Length << 3;

	freeString(ax25_data);
	return result;
}

void fx25_get_new_frame(int snd_ch, TStringList * frame_stream)
{
	string * myTemp;

	tx_bs_bit[snd_ch] = 0;
	tx_bit_cnt[snd_ch] = 0;
	tx_flag_cnt[snd_ch] = 0;
	tx_bit_stuff_cnt[snd_ch] = 0;
	tx_fx25_size_cnt[snd_ch] = 0;
	tx_fx25_size[snd_ch] = 1;
	tx_frame_status[snd_ch] = FRAME_NEW_FRAME;
	tx_byte_status[snd_ch] = BYTE_EMPTY;
	if (frame_stream->Count == 0)
		tx_frame_status[snd_ch] = FRAME_NO_FRAME;
	else
	{
		// We now pass control byte and ack bytes on front and pointer to socket on end if ackmode

		myTemp = Strings(frame_stream, 0);			// get message

		if ((myTemp->Data[0] & 0x0f) == 12)			// ACKMODE
		{
			// Save copy then copy data up 3 bytes

			Add(&KISS_acked[snd_ch], duplicateString(myTemp));

			mydelete(myTemp, 0, 3);
			myTemp->Length -= sizeof(void *);
		}
		else
		{
			// Just remove control 

			mydelete(myTemp, 0, 1);
		}

		AGW_AX25_frame_analiz(snd_ch, FALSE, myTemp);
		put_frame(snd_ch, myTemp, "", TRUE, FALSE);

		tx_data[snd_ch] = fill_fx25_data(snd_ch, myTemp);

		Delete(frame_stream, 0);			// This will invalidate temp
	}
}

int fx25_get_new_bit(int snd_ch, Byte bit)
{
	string *s;

	if (tx_frame_status[snd_ch] == FRAME_EMPTY)
	{
		fx25_get_new_frame(snd_ch, &all_frame_buf[snd_ch]);
		if (tx_frame_status[snd_ch] == FRAME_NEW_FRAME)
			tx_frame_status[snd_ch] = FRAME_FULL;
	}

	if (tx_frame_status[snd_ch] == FRAME_FULL)
	{
		if (tx_byte_status[snd_ch] == BYTE_EMPTY)
		{
			if (tx_data[snd_ch]->Length)
			{
				s = tx_data[snd_ch];

				tx_bit_stream[snd_ch] = s->Data[0];
				tx_frame_status[snd_ch] = FRAME_FULL;
				tx_byte_status[snd_ch] = BYTE_FULL;
				tx_bit_cnt[snd_ch] = 0;
				mydelete(tx_data[snd_ch], 0, 1);
			}
			else
				tx_frame_status[snd_ch] = FRAME_EMPTY;
		}
		if (tx_byte_status[snd_ch] == BYTE_FULL)
		{
			bit = tx_bit_stream[snd_ch] & TX_BIT1;
			tx_bit_stream[snd_ch] = tx_bit_stream[snd_ch] >> 1;
			tx_bit_cnt[snd_ch]++;
			tx_fx25_size_cnt[snd_ch]++;
			if (tx_bit_cnt[snd_ch] >= 8)
				tx_byte_status[snd_ch] = BYTE_EMPTY;
			if (tx_fx25_size_cnt[snd_ch] == tx_fx25_size[snd_ch])
				tx_frame_status[snd_ch] = FRAME_EMPTY;
		}
	}

	if (tx_frame_status[snd_ch] == FRAME_EMPTY)
	{
		fx25_get_new_frame(snd_ch, &all_frame_buf[snd_ch]);

		switch (tx_frame_status[snd_ch])
		{
		case FRAME_NEW_FRAME:
			tx_frame_status[snd_ch] = FRAME_FULL;
			break;

		case FRAME_NO_FRAME:
			tx_tail_cnt[snd_ch] = 0;
			tx_frame_status[snd_ch] = FRAME_EMPTY;
			tx_status[snd_ch] = TX_TAIL;
			break;
		}
	}
	return bit;
}


//////////////////


int get_new_bit_tail(UCHAR snd_ch, UCHAR bit)
{
	long _txtail = 0;
	UCHAR _diddles;

	if (modem_mode[snd_ch] == MODE_FSK)
		_diddles = diddles;
	else
		_diddles = 0;

	if (modem_mode[snd_ch] == MODE_FSK)
		_txtail = txtail[snd_ch];

	else if (modem_mode[snd_ch] == MODE_BPSK)
		_txtail = txtail[snd_ch];

	else if (modem_mode[snd_ch] == MODE_8PSK)
		_txtail = txtail[snd_ch] * 3;

	else if (modem_mode[snd_ch] == MODE_QPSK || modem_mode[snd_ch] == MODE_PI4QPSK)
	  _txtail = txtail[snd_ch] << 1;
  
	else if (modem_mode[snd_ch] == MODE_MPSK)
		_txtail = txtail[snd_ch] << 2;

	_txtail = (_txtail * tx_baudrate[snd_ch]) / 1000;

	if (qpsk_set[snd_ch].mode == QPSK_V26 || modem_mode[snd_ch] == MODE_8PSK)
		_diddles = 2;

	switch (_diddles)
	{
	case 0:
    
		if (tx_tail_cnt[snd_ch] < _txtail)
		{
			bit = TX_BIT0;
			tx_tail_cnt[snd_ch]++;
		}
		else
		{
			tx_status[snd_ch] = TX_WAIT_BPF;
		}

		break;

	case 1:

		if (tx_tail_cnt[snd_ch] < _txtail)
		{
			if (tx_last_diddle[snd_ch] == TX_BIT0)
				bit = TX_BIT1;
			else
				bit = TX_BIT0;

			tx_tail_cnt[snd_ch]++;
			tx_last_diddle[snd_ch] = bit;
		}
		else
		{
			tx_status[snd_ch] = TX_WAIT_BPF;
		}
		
		break;
	
	case 2:
    
		if (tx_tail_cnt[snd_ch] < _txtail)
		{
			bit = FRAME_FLAG >> (tx_tail_cnt[snd_ch] % 8) & 1;
			tx_tail_cnt[snd_ch]++;
		}
		else
		{
			tx_status[snd_ch] = TX_WAIT_BPF;
		}
		break;
	}
	return bit;
}

int get_new_bit_delay(UCHAR snd_ch, UCHAR bit)
{
	ULONG _txdelay = 0;
	UCHAR _diddles;

	_diddles = 0;

	switch (modem_mode[snd_ch])
	{
	case MODE_FSK:
	
		_diddles = diddles;
		break;

	case MODE_PI4QPSK:
	case MODE_8PSK:

		_diddles = 2;
		break;

    case MODE_QPSK:
		
		if (qpsk_set[snd_ch].mode == QPSK_V26)
			_diddles = 2;
		break;
	}

	if (modem_mode[snd_ch] == MODE_FSK)
		_txdelay = txdelay[snd_ch];

	else if (modem_mode[snd_ch] == MODE_BPSK)
		_txdelay = txdelay[snd_ch];

	else if (modem_mode[snd_ch] == MODE_8PSK)
		_txdelay = txdelay[snd_ch] * 3;

	else if (modem_mode[snd_ch] == MODE_QPSK || modem_mode[snd_ch] == MODE_PI4QPSK)
		_txdelay = txdelay[snd_ch] << 1;

	else if (modem_mode[snd_ch] == MODE_MPSK)
	{
		if (txdelay[snd_ch] < 400)
			_txdelay = 400 << 2;		 //AFC delay
		else
			_txdelay = txdelay[snd_ch] << 2;
	}
	
	_txdelay = (_txdelay * tx_baudrate[snd_ch]) / 1000;

	switch (_diddles)
	{
	case 0:
   
		if (tx_delay_cnt[snd_ch] < _txdelay)
		{
			bit = TX_BIT0;
			tx_delay_cnt[snd_ch]++;
		}
		else
		{
			tx_status[snd_ch] = TX_FRAME;
		}

		break;	
	
	case 1:
    
		if (tx_delay_cnt[snd_ch] < _txdelay)
		{
			if (tx_last_diddle[snd_ch] == TX_BIT0)
				bit = TX_BIT1;
			else
				bit = TX_BIT0;
		
			tx_delay_cnt[snd_ch]++;
			tx_last_diddle[snd_ch] = bit;
		}
		else
		{
			tx_status[snd_ch] = TX_FRAME;
			Debugprintf("End TXD %d", SampleNo);
		}
		break;

	case 2:

		// Send Flags

		if (tx_delay_cnt[snd_ch] < _txdelay)
		{
			bit = FRAME_FLAG >> ((8 - (_txdelay % 8) + tx_delay_cnt[snd_ch]) % 8) & 1;
			tx_delay_cnt[snd_ch]++;
		}
		else
		{
			tx_status[snd_ch] = TX_FRAME;
			Debugprintf("End TXD %d", SampleNo);
		}
		break;
	}
	return bit;
}

// is this waiting for the filter to fill?
// No, flushing BPF

void get_wait_bpf(UCHAR snd_ch)
{
	tx_BPF_timer[snd_ch]++;

	if (tx_BPF_timer[snd_ch] == tx_BPF_tap[snd_ch] )
	{
		tx_status[snd_ch] = TX_NO_DATA;
		tx_BPF_timer[snd_ch] = 0;
	}
}


//procedure modulator(snd_ch: byte; var buf: array of single; buf_size: word};
//{
/*
function filter(x,k: single}: single;
begin
  result = k*cos(x};
  if result>1 then result = 1;
  if result<-1 then result = -1;
end;
}
*/

single filter(single x)
{
	if (x <= PI25)
		return 1.0f;

	if (x >= PI75)
		return  -1.0f;

     return cosf(2.0f * x -PI5);
}


// make_samples return one sample of the waveform

// But seems to be called only once per bit ??

// No, but needs to preserve bit between calls 

float make_samples(unsigned char  snd_ch, unsigned char * bitptr)
{
	float pi2, x1, x;
	Byte i,qbit,tribit,dibit;
	float z1,z2,z3,z4;
	unsigned short b, msb, lsb;
	unsigned char bit = *bitptr;

	float amp = 0;

	pi2 = 2 * pi / TX_Samplerate;
	x1 = pi * tx_baudrate[snd_ch] / TX_Samplerate;

	if (modem_mode[snd_ch] == MODE_FSK)
	{
		if (bit == TX_BIT0)
			x = pi2*(tx_freq[snd_ch] + 0.5f * tx_shift[snd_ch]);
		else
			x = pi2*(tx_freq[snd_ch] - 0.5f * tx_shift[snd_ch]);

	   amp = 1.0f;

	    if (tx_baudrate[snd_ch] > 600)
		{
			if (tx_hitoneraisedb[snd_ch] < 0 && bit == TX_BIT0)
				amp = tx_hitoneraise[snd_ch];

			if (tx_hitoneraisedb[snd_ch] > 0 && bit == TX_BIT1)
				amp = tx_hitoneraise[snd_ch];
		}

		tx_osc[snd_ch] = tx_osc[snd_ch] + x;

		if (tx_osc[snd_ch] > 2*pi)
			tx_osc[snd_ch] = tx_osc[snd_ch] - 2*pi;
	}

	else if (modem_mode[snd_ch] == MODE_BPSK)
	{
		if (tx_change_phase[snd_ch])
			tx_bit_mod[snd_ch] = tx_inv[snd_ch] * cos(tx_bit_osc[snd_ch]);

		x = pi2 * (tx_freq[snd_ch]);

		tx_osc[snd_ch] = tx_osc[snd_ch] + x;

		if (tx_osc[snd_ch] > 2 * pi)
			tx_osc[snd_ch] = tx_osc[snd_ch] - 2 * pi;
	}

	else if (modem_mode[snd_ch] == MODE_QPSK)
	{
		if (tx_QPSK_old_I[snd_ch] != tx_QPSK_I[snd_ch])

			tx_I_mod[snd_ch] = tx_QPSK_avg_I[snd_ch] + tx_QPSK_df_I[snd_ch] * filter(tx_bit_osc[snd_ch]);
		else
			tx_I_mod[snd_ch] = tx_QPSK_I[snd_ch];

		if (tx_QPSK_old_Q[snd_ch] != tx_QPSK_Q[snd_ch])
			tx_Q_mod[snd_ch] = tx_QPSK_avg_Q[snd_ch] + tx_QPSK_df_Q[snd_ch] * filter(tx_bit_osc[snd_ch]);
		else
			tx_Q_mod[snd_ch] = tx_QPSK_Q[snd_ch];

		x = pi2 * (tx_freq[snd_ch]);
		tx_osc[snd_ch] = tx_osc[snd_ch] + x;
		if (tx_osc[snd_ch] > 2 * pi)
			tx_osc[snd_ch] = tx_osc[snd_ch] - 2 * pi;
	}
  
	else if (modem_mode[snd_ch] == MODE_8PSK || modem_mode[snd_ch] == MODE_PI4QPSK)
	{
		if (tx_8PSK_old_I[snd_ch] != tx_8PSK_I[snd_ch])
			tx_I_mod[snd_ch] = tx_8PSK_avg_I[snd_ch] + tx_8PSK_df_I[snd_ch] * filter(tx_bit_osc[snd_ch]);
		else
			tx_I_mod[snd_ch] = tx_8PSK_I[snd_ch];

		if (tx_8PSK_old_Q[snd_ch] != tx_8PSK_Q[snd_ch])
			tx_Q_mod[snd_ch] = tx_8PSK_avg_Q[snd_ch] + tx_8PSK_df_Q[snd_ch] * filter(tx_bit_osc[snd_ch]);
		else
			tx_Q_mod[snd_ch] = tx_8PSK_Q[snd_ch];

		x = pi2 * (tx_freq[snd_ch]);
		tx_osc[snd_ch] = tx_osc[snd_ch] + x;

		if (tx_osc[snd_ch] > 2 * pi)
			tx_osc[snd_ch] = tx_osc[snd_ch] - 2 * pi;

	}

	else if (modem_mode[snd_ch] == MODE_MPSK)
	{
		z1 = pi2 * (tx_freq[snd_ch] + ch_offset[0]);
		z2 = pi2 * (tx_freq[snd_ch] + ch_offset[1]);
		z3 = pi2 * (tx_freq[snd_ch] + ch_offset[2]);
		z4 = pi2 * (tx_freq[snd_ch] + ch_offset[3]);

		tx_osc1[snd_ch] = tx_osc1[snd_ch] + z1;
		tx_osc2[snd_ch] = tx_osc2[snd_ch] + z2;
		tx_osc3[snd_ch] = tx_osc3[snd_ch] + z3;
		tx_osc4[snd_ch] = tx_osc4[snd_ch] + z4;

		if (tx_osc1[snd_ch] > 2 * pi)
			tx_osc1[snd_ch] = tx_osc1[snd_ch] - 2 * pi;

		if (tx_osc2[snd_ch] > 2 * pi)
			tx_osc2[snd_ch] = tx_osc2[snd_ch] - 2 * pi;

		if (tx_osc3[snd_ch] > 2 * pi)
			tx_osc3[snd_ch] = tx_osc3[snd_ch] - 2 * pi;

		if (tx_osc4[snd_ch] > 2 * pi)
			tx_osc4[snd_ch] = tx_osc4[snd_ch] - 2 * pi;

		if (tx_old_inv1[snd_ch] != tx_inv1[snd_ch])
			tx_bit1_mod[snd_ch] = tx_inv1[snd_ch] * cos(tx_bit_osc[snd_ch]);
		else
			tx_bit1_mod[snd_ch] = -tx_inv1[snd_ch];

		if (tx_old_inv2[snd_ch] != tx_inv2[snd_ch])
			tx_bit2_mod[snd_ch] = tx_inv2[snd_ch] * cos(tx_bit_osc[snd_ch]);
		else 
			tx_bit2_mod[snd_ch] = -tx_inv2[snd_ch];

		if (tx_old_inv3[snd_ch] != tx_inv3[snd_ch])
			tx_bit3_mod[snd_ch] = tx_inv3[snd_ch] * cos(tx_bit_osc[snd_ch]);
		else 
			tx_bit3_mod[snd_ch] = -tx_inv3[snd_ch];

		if (tx_old_inv4[snd_ch] != tx_inv4[snd_ch]) 
			tx_bit4_mod[snd_ch] = tx_inv4[snd_ch] * cos(tx_bit_osc[snd_ch]);
		else
			tx_bit4_mod[snd_ch] = -tx_inv4[snd_ch];
	}

	tx_bit_osc[snd_ch] = tx_bit_osc[snd_ch] + x1;

	if (tx_bit_osc[snd_ch] > pi)
	{
		// This seems to get the next bit,
		// but why?? - end of samples for last bit

		tx_bit_osc[snd_ch] = tx_bit_osc[snd_ch] - pi;

		// FSK Mode
		if (modem_mode[snd_ch] == MODE_FSK)
		{
			bit = 0;

			if (tx_status[snd_ch] == TX_SILENCE)
			{
				tx_delay_cnt[snd_ch] = 0;
				tx_status[snd_ch] = TX_DELAY;
			}
	
			if (il2p_mode[snd_ch] >= IL2P_MODE_TXRX)
			{
				// il2p generates TXDELAY as part of the frame, so go straight to TX_FRAME
			
				if (tx_status[snd_ch] == TX_DELAY)
					tx_status[snd_ch] = TX_FRAME;
	
				if (tx_status[snd_ch] == TX_TAIL)
					bit = il2p_get_new_bit_tail(snd_ch, bit);

				if (tx_status[snd_ch] == TX_FRAME)
					bit = il2p_get_new_bit(snd_ch, bit);


				// No nrzi for il2p

				*bitptr = bit;
			}
			else
			{
				// ax25/fx25

				if (tx_status[snd_ch] == TX_DELAY)
					bit = get_new_bit_delay(snd_ch, bit);

				if (tx_status[snd_ch] == TX_TAIL)
					bit = get_new_bit_tail(snd_ch, bit);

				if (tx_status[snd_ch] == TX_FRAME)
				{
					if (tx_fx25_mode[snd_ch])
						bit = fx25_get_new_bit(snd_ch, bit);
					else
						bit = get_new_bit(snd_ch, bit);
				}
				
				*bitptr = tx_nrzi(snd_ch, bit);

			}

		}

		// BPSK Mode
		if (modem_mode[snd_ch] == MODE_BPSK)
		{
			bit = 0;

			if (tx_status[snd_ch] == TX_SILENCE)
			{
				tx_delay_cnt[snd_ch] = 0;
				tx_status[snd_ch] = TX_DELAY;
			}

			// il2p generates TXDELAY as part of the frame, so go straight to TX_FRAME

			if (tx_status[snd_ch] == TX_DELAY)
				if (il2p_mode[snd_ch] >= IL2P_MODE_TXRX)
					tx_status[snd_ch] = TX_FRAME;
				else
					bit = get_new_bit_delay(snd_ch, bit);

			if (tx_status[snd_ch] == TX_TAIL)
			{
				if (il2p_mode[snd_ch] >= IL2P_MODE_TXRX)
					bit = il2p_get_new_bit_tail(snd_ch, bit);
				else
					bit = get_new_bit_tail(snd_ch, bit);
			}

			if (tx_status[snd_ch] == TX_FRAME)
			{
				if (il2p_mode[snd_ch] >= IL2P_MODE_TXRX)
					bit = il2p_get_new_bit(snd_ch, bit);
				else if (tx_fx25_mode[snd_ch])
					bit = fx25_get_new_bit(snd_ch, bit);
				else
					bit = get_new_bit(snd_ch, bit);
			}
			
			// ??			*bitptr = tx_nrzi(snd_ch, bit);

			if (bit == 0)
			{
				tx_inv[snd_ch] = -tx_inv[snd_ch];
				tx_change_phase[snd_ch] = TRUE;
			}
			else
				tx_change_phase[snd_ch] = FALSE;
		}

		// QPSK Mode

		else if (modem_mode[snd_ch] == MODE_QPSK)
		{
			dibit = 0;
			for (i = 0; i < 2; i++)
			{
				bit = 0;
				if (tx_status[snd_ch] == TX_SILENCE)
				{
					tx_delay_cnt[snd_ch] = 0;
					tx_status[snd_ch] = TX_DELAY;
				}

				if (il2p_mode[snd_ch] >= IL2P_MODE_TXRX)
				{
					if (tx_status[snd_ch] == TX_DELAY)
						tx_status[snd_ch] = TX_FRAME;			// il2p generates TXDELAY as part of the frame, so go straight to TX_FRAME

					if (tx_status[snd_ch] == TX_TAIL)
						bit = il2p_get_new_bit_tail(snd_ch, bit);

					if (tx_status[snd_ch] == TX_FRAME)
						bit = il2p_get_new_bit(snd_ch, bit);

					// No nrzi for il2p

					dibit = (dibit << 1) | bit;
				}
				else
				{
					// ax25/fx25

					if (tx_status[snd_ch] == TX_DELAY)
						bit = get_new_bit_delay(snd_ch, bit);
					if (tx_status[snd_ch] == TX_TAIL)
						bit = get_new_bit_tail(snd_ch, bit);
					if (tx_status[snd_ch] == TX_FRAME)
						bit = get_new_bit(snd_ch, bit);
					dibit = (dibit << 1) | tx_nrzi(snd_ch, bit);

				}
			}


			dibit = qpsk_set[snd_ch].tx[dibit & 3];
			tx_QPSK[snd_ch] = (tx_QPSK[snd_ch] + dibit) & 3;
			tx_QPSK_old_I[snd_ch] = tx_QPSK_I[snd_ch];
			tx_QPSK_old_Q[snd_ch] = tx_QPSK_Q[snd_ch];

			switch (tx_QPSK[snd_ch])
			{
			case 0:

				tx_QPSK_I[snd_ch] = COS45;
				tx_QPSK_Q[snd_ch] = COS45;
				break;

			case 1:

				tx_QPSK_I[snd_ch] = -COS45;
				tx_QPSK_Q[snd_ch] = COS45;
				break;

			case 2:

				tx_QPSK_I[snd_ch] = -COS45;
				tx_QPSK_Q[snd_ch] = -COS45;
				break;

			case 3:

				tx_QPSK_I[snd_ch] = COS45;
				tx_QPSK_Q[snd_ch] = -COS45;
				break;
			}

			tx_QPSK_avg_I[snd_ch] = 0.5f*(tx_QPSK_old_I[snd_ch] + tx_QPSK_I[snd_ch]);
			tx_QPSK_df_I[snd_ch] = 0.5f*(tx_QPSK_old_I[snd_ch] - tx_QPSK_I[snd_ch]);
			tx_QPSK_avg_Q[snd_ch] = 0.5f*(tx_QPSK_old_Q[snd_ch] + tx_QPSK_Q[snd_ch]);
			tx_QPSK_df_Q[snd_ch] = 0.5f*(tx_QPSK_old_Q[snd_ch] - tx_QPSK_Q[snd_ch]);
		}

		// PI/4 QPSK Mode

		if (modem_mode[snd_ch] == MODE_PI4QPSK)
		{
			dibit = 0;

			for (i = 0; i < 2; i++)
			{
				bit = 0;
				if (tx_status[snd_ch] == TX_SILENCE)
				{
					tx_delay_cnt[snd_ch] = 0;
					tx_status[snd_ch] = TX_DELAY;
				}

				if (il2p_mode[snd_ch] >= IL2P_MODE_TXRX)
				{
					if (tx_status[snd_ch] == TX_DELAY)
						tx_status[snd_ch] = TX_FRAME;			// il2p generates TXDELAY as part of the frame, so go straight to TX_FRAME

					if (tx_status[snd_ch] == TX_TAIL)
						bit = il2p_get_new_bit_tail(snd_ch, bit);

					if (tx_status[snd_ch] == TX_FRAME)
						bit = il2p_get_new_bit(snd_ch, bit);

					// No nrzi for il2p

					dibit = (dibit << 1) | bit;
				}
				else
				{
					// ax25/fx25

					if (tx_status[snd_ch] == TX_DELAY)
						bit = get_new_bit_delay(snd_ch, bit);

					if (tx_status[snd_ch] == TX_TAIL)
						bit = get_new_bit_tail(snd_ch, bit);

					if (tx_status[snd_ch] == TX_FRAME)
						bit = get_new_bit(snd_ch, bit);

					*bitptr = tx_nrzi(snd_ch, bit);
			
					dibit = (dibit << 1) | *bitptr;
				}
			}

			// This returns 3,1,5 or 7 so we use the odd enties in the 8PSK table

			dibit = gray_PI4QPSK[dibit & 3];

			tx_8PSK[snd_ch] = (tx_8PSK[snd_ch] + dibit) & 7;
			tx_8PSK_old_I[snd_ch] = tx_8PSK_I[snd_ch];
			tx_8PSK_old_Q[snd_ch] = tx_8PSK_Q[snd_ch];

			switch (tx_8PSK[snd_ch])
			{
			case 0:
				tx_8PSK_I[snd_ch] = 0;
				tx_8PSK_Q[snd_ch] = 1;
				break;

			case 1:
				tx_8PSK_I[snd_ch] = COS45;
				tx_8PSK_Q[snd_ch] = COS45;
				break;

			case 2:
				tx_8PSK_I[snd_ch] = 1;
				tx_8PSK_Q[snd_ch] = 0;
				break;

			case 3:
				tx_8PSK_I[snd_ch] = COS45;
				tx_8PSK_Q[snd_ch] = -COS45;
				break;

			case 4:
				tx_8PSK_I[snd_ch] = 0;
				tx_8PSK_Q[snd_ch] = -1;
				break;

			case 5:
				tx_8PSK_I[snd_ch] = -COS45;
				tx_8PSK_Q[snd_ch] = -COS45;
				break;

			case 6:
				tx_8PSK_I[snd_ch] = -1;
				tx_8PSK_Q[snd_ch] = 0;
				break;

			case 7:
				tx_8PSK_I[snd_ch] = -COS45;
				tx_8PSK_Q[snd_ch] = COS45;
				break;

			}

			tx_8PSK_avg_I[snd_ch] = 0.5*(tx_8PSK_old_I[snd_ch] + tx_8PSK_I[snd_ch]);
			tx_8PSK_df_I[snd_ch] = 0.5*(tx_8PSK_old_I[snd_ch] - tx_8PSK_I[snd_ch]);
			tx_8PSK_avg_Q[snd_ch] = 0.5*(tx_8PSK_old_Q[snd_ch] + tx_8PSK_Q[snd_ch]);
			tx_8PSK_df_Q[snd_ch] = 0.5*(tx_8PSK_old_Q[snd_ch] - tx_8PSK_Q[snd_ch]);

		}
		
		// 8PSK Mode

		if (modem_mode[snd_ch] == MODE_8PSK)
		{
			tribit = 0;
			for (i = 0; i < 3; i++)
			{
				bit = 0;

				if (tx_status[snd_ch] == TX_SILENCE)
				{
					tx_delay_cnt[snd_ch] = 0;
					tx_status[snd_ch] = TX_DELAY;
				}

				if (il2p_mode[snd_ch] >= IL2P_MODE_TXRX)
				{
					if (tx_status[snd_ch] == TX_DELAY)
						tx_status[snd_ch] = TX_FRAME;			// il2p generates TXDELAY as part of the frame, so go straight to TX_FRAME

					if (tx_status[snd_ch] == TX_TAIL)
						bit = il2p_get_new_bit_tail(snd_ch, bit);

					if (tx_status[snd_ch] == TX_FRAME)
						bit = il2p_get_new_bit(snd_ch, bit);

					// No nrzi for il2p

					tribit = (tribit << 1) | bit;
				}
				else
				{
					// ax25/fx25

					if (tx_status[snd_ch] == TX_DELAY)
						bit = get_new_bit_delay(snd_ch, bit);
					if (tx_status[snd_ch] == TX_TAIL)
						bit = get_new_bit_tail(snd_ch, bit);
					if (tx_status[snd_ch] == TX_FRAME)
						bit = get_new_bit(snd_ch, bit);

					tribit = (tribit << 1) | tx_nrzi(snd_ch, bit);
				}
			}
			tribit = gray_8PSK[tribit & 7];

			tx_8PSK[snd_ch] = (tx_8PSK[snd_ch] + tribit) & 7;
			tx_8PSK_old_I[snd_ch] = tx_8PSK_I[snd_ch];
			tx_8PSK_old_Q[snd_ch] = tx_8PSK_Q[snd_ch];

			switch (tx_8PSK[snd_ch])
			{
			case 0:

				tx_8PSK_I[snd_ch] = 0;
				tx_8PSK_Q[snd_ch] = 1;
				break;

			case 1:

				tx_8PSK_I[snd_ch] = COS45;
				tx_8PSK_Q[snd_ch] = COS45;
				break;

			case 2:

				tx_8PSK_I[snd_ch] = 1;
				tx_8PSK_Q[snd_ch] = 0;
				break;

			case 3:

				tx_8PSK_I[snd_ch] = COS45;
				tx_8PSK_Q[snd_ch] = -COS45;
				break;

			case 4:

				tx_8PSK_I[snd_ch] = 0;
				tx_8PSK_Q[snd_ch] = -1;
				break;

			case 5:

				tx_8PSK_I[snd_ch] = -COS45;
				tx_8PSK_Q[snd_ch] = -COS45;
				break;

			case 6:

				tx_8PSK_I[snd_ch] = -1;
				tx_8PSK_Q[snd_ch] = 0;
				break;

			case 7:

				tx_8PSK_I[snd_ch] = -COS45;
				tx_8PSK_Q[snd_ch] = COS45;
				break;

			}

			tx_8PSK_avg_I[snd_ch] = 0.5f*(tx_8PSK_old_I[snd_ch] + tx_8PSK_I[snd_ch]);
			tx_8PSK_df_I[snd_ch] = 0.5f*(tx_8PSK_old_I[snd_ch] - tx_8PSK_I[snd_ch]);
			tx_8PSK_avg_Q[snd_ch] = 0.5f*(tx_8PSK_old_Q[snd_ch] + tx_8PSK_Q[snd_ch]);
			tx_8PSK_df_Q[snd_ch] = 0.5f*(tx_8PSK_old_Q[snd_ch] - tx_8PSK_Q[snd_ch]);
		}
					
		if (modem_mode[snd_ch] == MODE_MPSK)
		{
			qbit = 0;

			// get the bits for each of 4 carriers

			for (i = 1; i <= 4; i++)
			{
				bit = 0;

				if (tx_status[snd_ch] == TX_SILENCE)
				{
					tx_delay_cnt[snd_ch] = 0;
					tx_status[snd_ch] = TX_DELAY;
				}

				if (tx_status[snd_ch] == TX_DELAY)
					bit = get_new_bit_delay(snd_ch, bit);

				if (tx_status[snd_ch] == TX_TAIL)
					bit = get_new_bit_tail(snd_ch, bit);

				if (tx_status[snd_ch] == TX_FRAME)
					bit = get_new_bit(snd_ch, bit);

				qbit = (qbit << 1) | bit;
			}

			tx_old_inv1[snd_ch] = tx_inv1[snd_ch];
			tx_old_inv2[snd_ch] = tx_inv2[snd_ch];
			tx_old_inv3[snd_ch] = tx_inv3[snd_ch];
			tx_old_inv4[snd_ch] = tx_inv4[snd_ch];

			if ((qbit & 8) == 0)
				tx_inv1[snd_ch] = -tx_inv1[snd_ch];
			if ((qbit & 4) == 0)
				tx_inv2[snd_ch] = -tx_inv2[snd_ch];
			if ((qbit & 2) == 0)
				tx_inv3[snd_ch] = -tx_inv3[snd_ch];
			if ((qbit & 1) == 0)
				tx_inv4[snd_ch] = -tx_inv4[snd_ch];

		}
	}

	if (tx_status[snd_ch] == TX_WAIT_BPF)
		get_wait_bpf(snd_ch);

	if (modem_mode[snd_ch] == MODE_FSK)
		return amp * sinf(tx_osc[snd_ch]);

	if (modem_mode[snd_ch] == MODE_BPSK)
		return sinf(tx_osc[snd_ch]) * tx_bit_mod[snd_ch];

	if (modem_mode[snd_ch] == MODE_QPSK || modem_mode[snd_ch] == MODE_8PSK || modem_mode[snd_ch] == MODE_PI4QPSK)
		return sin(tx_osc[snd_ch]) * tx_I_mod[snd_ch] + cos(tx_osc[snd_ch]) * tx_Q_mod[snd_ch];

	if (modem_mode[snd_ch] == MODE_MPSK)
		return 0.35*(sinf(tx_osc1[snd_ch])*tx_bit1_mod[snd_ch] +
			sinf(tx_osc2[snd_ch])*tx_bit2_mod[snd_ch] +
			sinf(tx_osc3[snd_ch])*tx_bit3_mod[snd_ch] +
			sinf(tx_osc4[snd_ch])*tx_bit4_mod[snd_ch]);

	return 0.0f;
}

float make_samples_calib(UCHAR snd_ch, UCHAR tones)
{
	float amp, pi2, x, x1;

	x1 = pi * tx_baudrate[snd_ch] / TX_Samplerate;
	pi2 = 2 * pi / TX_Samplerate;

	switch (tones)
	{
	case 1:

		tx_last_bit[snd_ch] = 1;
		break;

	case 2:

		tx_last_bit[snd_ch] = 0;
		break;

	case 3:

		tx_bit_osc[snd_ch] = tx_bit_osc[snd_ch] + x1;

		if (tx_bit_osc[snd_ch] > pi)
		{
			tx_bit_osc[snd_ch] = tx_bit_osc[snd_ch] - pi;
			tx_last_bit[snd_ch] = tx_last_bit[snd_ch] ^ 1;
		}
		break;
	}

	amp = 1;

	if (tx_baudrate[snd_ch] > 600)
	{
		if (tx_hitoneraisedb[snd_ch] < 0 && tx_last_bit[snd_ch] == 0)
			amp = tx_hitoneraise[snd_ch];

		if (tx_hitoneraisedb[snd_ch] > 0 && tx_last_bit[snd_ch] == 1)
			amp = tx_hitoneraise[snd_ch];
	}
	
	if (tx_last_bit[snd_ch] == 0)
		x = pi2*(tx_freq[snd_ch] + 0.5f * tx_shift[snd_ch]);
	else
		x = pi2*(tx_freq[snd_ch] - 0.5f * tx_shift[snd_ch]);

	tx_osc[snd_ch] = tx_osc[snd_ch] + x;
	
	if (tx_osc[snd_ch] > 2*pi)
		tx_osc[snd_ch] = tx_osc[snd_ch] - 2 * pi;

	return amp * sinf(tx_osc[snd_ch]);
}

float amplitude = 32000;

void modulator(UCHAR snd_ch, int buf_size)
{
	// We feed samples to samplesink instead of buffering them

	// I think this is the top of the TX hierarchy

	int i;
	int Sample;

	if (calib_mode[snd_ch] > 0)
	{
		if (calib_mode[snd_ch] == 4)		// CWID
		{
			if (tx_status[snd_ch] == TX_SILENCE)
			{
				SoundIsPlaying = TRUE;
				Debugprintf("Start CWID Chan %d", snd_ch);
				RadioPTT(snd_ch, 1);

				tx_status[snd_ch] = 6;
			}

			if (ARDOPSendToCard(snd_ch, SendSize) == 1)
			{
				// End of TX

				tx_status[snd_ch] = TX_SILENCE;		// Stop TX
				Flush();
				RadioPTT(snd_ch, 0);
				Debugprintf("End CWID");
				calib_mode[snd_ch] = 0;
			}
			return;
		}


		if (tx_status[snd_ch] == TX_SILENCE)
		{
			SoundIsPlaying = TRUE;
			Debugprintf("Start Calib Chan %d", snd_ch);
			RadioPTT(snd_ch, 1);

			tx_bit_osc[snd_ch] = 0;
			tx_last_bit[snd_ch] = 0;
	
			// fill filter 

			for (i = 0; i < tx_BPF_tap[snd_ch]; i++)
				tx_prev_BPF_buf[snd_ch][buf_size + i] = make_samples_calib(snd_ch,calib_mode[snd_ch]);
		}
		tx_status[snd_ch] = TX_WAIT_BPF;
	
		for (i = 0; i < buf_size; i++)
			tx_src_BPF_buf[snd_ch][i] = make_samples_calib(snd_ch, calib_mode[snd_ch]);

		FIR_filter(tx_src_BPF_buf[snd_ch],buf_size,tx_BPF_tap[snd_ch],tx_BPF_core[snd_ch],tx_BPF_buf[snd_ch],tx_prev_BPF_buf[snd_ch]);
    
		for (i = 0; i < buf_size; i++)
		{
			Sample = tx_BPF_buf[snd_ch][i] * amplitude;

			if (Sample < txmin)
				txmin = Sample;
			else if (Sample > txmax)
				txmax = Sample;

			SampleSink(modemtoSoundLR[snd_ch], Sample);
		}
	}
	else
	{
		if (tx_status[snd_ch] == TX_SILENCE)
		{
			if (fx25_mode[snd_ch] == FX25_MODE_TXRX)
				tx_fx25_mode[snd_ch] = 1;
			else
				tx_fx25_mode[snd_ch] = 0;

			tx_bit_osc[snd_ch] = 0;
			tx_8PSK[snd_ch] = 0;
			tx_QPSK[snd_ch] = 0;
			tx_last_bit[snd_ch] = 0;
			tx_inv1[snd_ch] = 1;
			tx_inv2[snd_ch] = 1;
			tx_inv3[snd_ch] = 1;
			tx_inv4[snd_ch] = 1;
			tx_8PSK_I[snd_ch] =  0;
			tx_8PSK_Q[snd_ch] =  1;
			tx_8PSK_old_I[snd_ch] =  0;
			tx_8PSK_old_Q[snd_ch] =  1;
			tx_QPSK_I[snd_ch] =  COS45;
			tx_QPSK_Q[snd_ch] =  COS45;
			tx_QPSK_old_I[snd_ch] =  COS45;
			tx_QPSK_old_Q[snd_ch] =  COS45;

			for (i = 0; i < tx_BPF_tap[snd_ch]; i++)
				tx_prev_BPF_buf[snd_ch][buf_size+i] = make_samples(snd_ch, &tx_pol[snd_ch]);
		}
		
		for (i = 0; i < buf_size; i++)
			tx_src_BPF_buf[snd_ch][i] = make_samples(snd_ch, &tx_pol[snd_ch]);
		
		FIR_filter(tx_src_BPF_buf[snd_ch], buf_size, tx_BPF_tap[snd_ch], tx_BPF_core[snd_ch], tx_BPF_buf[snd_ch], tx_prev_BPF_buf[snd_ch]);

		for (i = 0; i < buf_size; i++)
		{
			Sample = tx_BPF_buf[snd_ch][i] * amplitude;

			if (Sample < txmin)
				txmin = Sample;
			else if (Sample > txmax)
			{
				txmax = Sample;

				if (txmax > 32767)
				{
					amplitude = amplitude * 32767 / txmax;
					txmax = 32767;
					Sample = 32767;
				}
			}

			SampleSink(modemtoSoundLR[snd_ch], Sample);
		}
	}
}