From 6b39f526b98e2d6ebe4774446cdf04c609c5eb44 Mon Sep 17 00:00:00 2001
From: David Freese <w1hkj@w1hkj.com>
Date: Wed, 21 Sep 2011 10:29:24 -0500
Subject: [PATCH] WWV xmt mode

  * Added sound card time tick transmit
---
 src/include/wwv.h | 11 ++++++++-
 src/trx/trx.cxx   |  5 ++--
 src/wwv/wwv.cxx   | 61 +++++++++++++++++++++++++++++++++++++++++++----
 3 files changed, 70 insertions(+), 7 deletions(-)

diff --git a/src/include/wwv.h b/src/include/wwv.h
index e129f24b..214cbb3e 100644
--- a/src/include/wwv.h
+++ b/src/include/wwv.h
@@ -69,6 +69,15 @@ protected:
 	bool			calc;
 	bool			zoom;
 
+	double	keyshape[32]; // 4 msec rise and fall time for pulse
+	double	audio[400];
+	double	quiet[400];
+	double	play[400];
+
+	double nco(double freq);
+	void makeshape();
+	void makeaudio();
+
 public:
 	wwv();
 	~wwv();
@@ -77,7 +86,7 @@ public:
 	void	tx_init(SoundBase *sc);
 	void 	restart() {};
 	int		rx_process(const double *buf, int len);
-	int		tx_process() {return -1;}
+	int		tx_process();
 	void	update_syncscope();
 	void	set1(int x, int y);
 	void	set2(int x, int y);
diff --git a/src/trx/trx.cxx b/src/trx/trx.cxx
index bd466be9..61ef5e6c 100644
--- a/src/trx/trx.cxx
+++ b/src/trx/trx.cxx
@@ -295,7 +295,6 @@ void trx_trx_transmit_loop()
 		MilliSleep(10);
 		return;
 	}
-
 	if (active_modem) {
 		try {
 		    current_samplerate = active_modem->get_samplerate();
@@ -314,7 +313,9 @@ void trx_trx_transmit_loop()
 		}
 		active_modem->tx_init(scard);
 
-		if ((active_modem != null_modem && active_modem != ssb_modem) && 
+		if ((active_modem != null_modem && 
+			active_modem != ssb_modem &&
+			active_modem != wwv_modem ) && 
 			progdefaults.TransmitRSid)
 			ReedSolomon->send(true);
 
diff --git a/src/wwv/wwv.cxx b/src/wwv/wwv.cxx
index 641a9332..284b736a 100644
--- a/src/wwv/wwv.cxx
+++ b/src/wwv/wwv.cxx
@@ -46,8 +46,6 @@ void wwv::rx_init()
 	phaseacc = 0.0;
 	smpl_ctr = 0;		// sample counter for timing wwv rx 
 	agc = 0.0;			// threshold for tick detection 
-//	sync = 0;
-//	sync0 = 0;
 	ticks = 0;
 	calc = false;
 	zoom = false;
@@ -87,8 +85,8 @@ wwv::wwv() : modem()
 	lpfilter->init_lowpass (FIRLEN_1, DEC_1, lp);
 	
 	vidfilter = new Cmovavg(16);
-	
-	cap &= ~CAP_TX;
+
+	makeaudio();
 }
 
 
@@ -165,3 +163,58 @@ void wwv::set2(int x, int y)
 	zoom = !zoom;
 }
 
+//======================================================================
+// transmit time tick
+//======================================================================
+
+void wwv::makeshape()
+{
+	for (int i = 0; i < 32; i++)
+		keyshape[i] = 0.5 * (1.0 - cos (M_PI * i / 32));
+}
+
+double wwv::nco(double freq)
+{
+	phaseacc += 2.0 * M_PI * freq / samplerate;
+
+	if (phaseacc > M_PI)
+		phaseacc -= 2.0 * M_PI;
+
+	return sin(phaseacc);
+}
+
+void wwv::makeaudio()
+{
+	phaseacc = 0.0;
+	makeshape();
+	for (int i = 0; i < 400; i++) {
+		audio[i] = (i < 200 ? nco(1000) : 0);
+		quiet[i] = 0;
+	}
+	for (int i = 0; i < 32; i++) {
+		audio[i] *= keyshape[i];
+		audio[199 - i] *= keyshape[i];
+	}
+}
+
+int wwv::tx_process() 
+{
+	static int cycle = 4;
+	int c = get_tx_char();
+
+	if (c == 0x03 || stopflag) {
+		stopflag = false;
+		return -1;
+	}
+	if (--cycle == 0) {
+		memcpy(play, audio, 400 * sizeof(double));
+		ModulateXmtr(play, 400);
+		cycle = 4;
+	} else
+		ModulateXmtr(quiet, 400);
+	ModulateXmtr(quiet, 400);
+	ModulateXmtr(quiet, 400);
+	ModulateXmtr(quiet, 400);
+	ModulateXmtr(quiet, 400);
+	return 0;
+}