BFM decoder: implement RDS decoder

plugins/channel/bfm/bfmdemod.cpp

@@ -137,11 +137,17 @@ void BFMDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
 			if (m_running.m_rdsActive)
 			{
 				//Complex r(demod * 2.0 * std::cos(3.0 * m_pilotPLLSamples[2]), 0.0);
-				Complex r(demod * 2.0 * std::cos(3.0 * m_pilotPLLSamples[2]), m_pilotPLLSamples[2]);
+				Complex r(demod * 2.0 * std::cos(3.0 * m_pilotPLLSamples[2]), 0.0);
 
 				if (m_interpolatorRDS.interpolate(&m_interpolatorRDSDistanceRemain, r, &cr))
 				{
-					m_rdsDemod.process(cr.real(), cr.imag());
+					bool bit;
+
+					if (m_rdsDemod.process(cr.real(), bit))
+					{
+						m_rdsDecoder.frameSync(bit);
+					}
+
 					m_interpolatorRDSDistanceRemain += m_interpolatorRDSDistance;
 				}
 			}

plugins/channel/bfm/bfmdemod.h

@@ -31,6 +31,7 @@
 #include "audio/audiofifo.h"
 #include "util/message.h"
 #include "rdsdemod.h"
+#include "rdsdecoder.h"
 
 #define rfFilterFftLength 1024
 
@@ -192,6 +193,7 @@ private:
 	Real m_pilotPLLSamples[3];
 
 	RDSDemod m_rdsDemod;
+	RDSDecoder m_rdsDecoder;
 
 	LowPassFilterRC m_deemphasisFilterX;
 	LowPassFilterRC m_deemphasisFilterY;

plugins/channel/bfm/rdsdemod.cpp

@@ -44,6 +44,7 @@ RDSDemod::RDSDemod() :
 	m_parms.prev_acc = 0;
 	m_parms.counter = 0;
 	m_parms.reading_frame = 0;
+	m_parms.dbit = 0;
 }
 
 RDSDemod::~RDSDemod()
@@ -55,8 +56,10 @@ void RDSDemod::setSampleRate(int srate) /// FIXME: fix rate for now
 {
 }
 
-void RDSDemod::process(Real demod, Real pilot)
+bool RDSDemod::process(Real demod, bool& bit)
 {
+	bool ret = false;
+
 	m_udpDebug.write(m_parms.lo_clock * m_parms.subcarr_bb[0]);
 
 	// Subcarrier downmix & phase recovery
@@ -101,7 +104,7 @@ void RDSDemod::process(Real demod, Real pilot)
 
 		if (sign(m_parms.lo_clock) != sign(m_parms.prev_lo_clock))
 		{
-			biphase(m_parms.acc, m_parms.clock_phi - m_parms.prev_clock_phi);
+			ret = biphase(m_parms.acc, bit, m_parms.clock_phi - m_parms.prev_clock_phi);
 			m_parms.acc = 0;
 		}
 
@@ -112,10 +115,13 @@ void RDSDemod::process(Real demod, Real pilot)
 	m_parms.prev_bb = m_parms.subcarr_bb[0];
 	m_parms.prev_clock_phi = m_parms.clock_phi;
 	m_prev = demod;
+
+	return ret;
 }
 
-void RDSDemod::biphase(Real acc, Real d_cphi)
+bool RDSDemod::biphase(Real acc, bool& bit, Real d_cphi)
 {
+	bool ret = false;
 
 	if (sign(acc) != sign(m_parms.prev_acc)) // two successive of different sign: error detected
 	{
@@ -124,7 +130,11 @@ void RDSDemod::biphase(Real acc, Real d_cphi)
 
 	if (m_parms.counter % 2 == m_parms.reading_frame) // two successive of the same sing: OK
 	{
-		// TODO: take action print_delta(sign(acc + prev_acc));
+		// new bit found
+		int b = sign(m_parms.acc + m_parms.prev_acc);
+		bit = b ^ m_parms.dbit;
+		m_parms.dbit = b;
+		ret = true;
 	}
 
 	if (m_parms.counter == 0)
@@ -149,6 +159,8 @@ void RDSDemod::biphase(Real acc, Real d_cphi)
 
 	m_parms.prev_acc = acc; // memorize (z^-1)
 	m_parms.counter = (m_parms.counter + 1) % 800;
+
+	return ret;
 }
 
 Real RDSDemod::filter_lp_2400_iq(Real input, int iqIndex)

plugins/channel/bfm/rdsdemod.h

@@ -32,10 +32,10 @@ public:
 	~RDSDemod();
 
 	void setSampleRate(int srate);
-	void process(Real rdsSample, Real pilotSample);
+	bool process(Real rdsSample, bool &bit);
 
 protected:
-	void biphase(Real acc, Real d_cphi);
+	bool biphase(Real acc, bool &bit, Real d_cphi);
 	Real filter_lp_2400_iq(Real in, int iqIndex);
 	Real filter_lp_pll(Real input);
 	int sign(Real a);
@@ -58,6 +58,7 @@ private:
 		int counter;
 		int reading_frame;
 		int tot_errs[2];
+		int dbit;
 	} m_parms;
 
 	Real m_xv[2][2+1];