- improvement: use Integrate and Dump filter

git-svn-id: http://moon:8086/svn/software/trunk/projects/GnuRadio@385 b431acfa-c32f-4a4a-93f1-934dc6c82436

gr-jay/lib/garage_impl.cc

@@ -26,7 +26,7 @@
 #include "garage_impl.h"
 	
 #define WITH_DEBUG_MESSAGES		0
-#define WITH_DEBUG_FILE			0
+#define WITH_DEBUG_FILE			1
 	
 namespace gr
 {
@@ -53,10 +53,11 @@ garage_impl::garage_impl(int sampleRate, int samplesPerSym, float kLoopFilter, f
 , m_vmin(0)
 , m_vmax(0)
 , m_v_sig(0)
-, m_v_sig_m(0.5f)
+, m_dc_corr(0)
-, m_v_thr(0)
 , m_lag_accu(0)
-, m_bit(0)
+, m_id_accu(0)
+, m_id_bit(0)
+, m_bitZeroCross(0)
 , m_i(0)
 , m_gapDistance(8*m_samplesPerSym)
 , m_gapCounter(0)
@@ -107,7 +108,7 @@ void garage_impl::forecast (int noutput_items, gr_vector_int &ninput_items_requi
 
 int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, gr_vector_const_void_star &input_items, gr_vector_void_star &output_items)
 {
-	float rho = 1e-4;
+	float rho = 0.999f;
 	const float *in = (const float *) input_items[0];
 	float *out = (float *) output_items[0];
 	int outCount = 0;
@@ -115,8 +116,8 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 	
 	// Do <+signal processing+>
 	int countReload = m_samplesPerSym-1;
-	float alpha_thr = 0.5f;
+	float alpha_thr = 0.002f;
-	float hyst_thr = 0.5f;
+	float hyst_thr = 0.1f;
 	float k_leadLag = m_kLoopFilter;
 	float loopThreshold = m_kThreshold;
 	float k_lead = 1.0e-1f;
@@ -125,52 +126,68 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 	float err = 0;
 	
 	float alpha_sig = 0.5f/m_samplesPerSym;
-	float alpha_sig_m = alpha_sig/5;
 	
 	int i_i = 0;
 	while ((i_i+1) < ninput_items[0])
 	{
 		// Get next interpolated sample
 		float i_f = m_i - (float)i_i;
-		float y = (1.f-i_f)*in[i_i] + i_f*in[i_i+1];
+		float y = (1.f-i_f)*in[i_i] + i_f*in[i_i+1] - m_dc_corr;
 		
 		// Calculate threshold
-		m_v_thr = (fabs(m_vmax) - fabs(m_vmin))/2;
+		m_vmin *= rho;
+		m_vmax *= rho;
 		if (y < m_vmin)
 		{
-			m_vmin = (1-alpha_thr)*m_vmin + alpha_thr*y;
+			m_vmin = y;
 		}
 		else if (y > m_vmax)
 		{
-			m_vmax = (1-alpha_thr)*m_vmax + alpha_thr*y;
+			m_vmax = y;
 		}
-		m_vmin = m_vmin + rho*(m_v_thr - m_vmin);
-		m_vmax = m_vmax + rho*(m_v_thr - m_vmax);
 
+		// Calculate DC offset correction
+		m_dc_corr += alpha_thr*(m_vmax + m_vmin);
+		
 		// Signal detection
-		float y_nodc = (y-m_v_thr);
+		m_v_sig = (1.f-alpha_sig)*m_v_sig + alpha_sig*y*y;
-		m_v_sig = (1.f-alpha_sig)*m_v_sig + alpha_sig*y_nodc*y_nodc;
-		m_v_sig_m = (1.f-alpha_sig_m)*m_v_sig_m + alpha_sig_m*y;
 		bool isSignal = m_v_sig >= loopThreshold;
 
+		// Integrate and dump
+		float k_id = 1.f/((1+m_lag_accu)*m_samplesPerSym);
+		m_id_accu += k_id*y;
+		if (m_count == m_samplesPerSym/2)
+		{
+			int bit_id = (int)(m_id_accu >= 0.0);
+			m_id_accu = 0;
+			out[outCount++] = (float)bit_id;
+			if (isSignal)
+			{
+				bitRecord(bit_id);
+				if (m_pFile_bits)
+				{
+					fprintf(m_pFile_bits, "%f %f\n", (float)m_sampleCounter/m_sampleRate, y);
+				}
+			}
+		}
+
+		// Zero crossing detector
 		int bitChg = 0;
 		if (isSignal)
 		{
-		
+			if (m_bitZeroCross == 1)
-			// Detect bit change
-			if (m_bit == 1)
 			{
-				if (y < (hyst_thr*m_v_thr))
+				if (y < -hyst_thr)
 				{
-					m_bit = 0;
+					m_bitZeroCross = 0;
 					bitChg = 1;
 				}
 			}
 			else 
 			{
-				if (y > (hyst_thr*m_v_thr))
+				if (y > +hyst_thr)
 				{
-					m_bit = 1;
+					m_bitZeroCross = 1;
 					bitChg = 1;
 				}
 			}
@@ -196,16 +213,7 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 		// Sample bit at baud rate = fs/numSamplesPerSym
 		if (m_count == 0)
 		{
-			out[outCount++] = (float)m_bit;
 			m_count = countReload;
-			if (isSignal)
-			{
-				bitRecord(m_bit);
-				if (m_pFile_bits)
-				{
-					fprintf(m_pFile_bits, "%f %f\n", (float)m_sampleCounter/m_sampleRate, y);
-				}
-			}
 		}
 		else
 		{
@@ -214,7 +222,7 @@ int garage_impl::general_work (int noutput_items, gr_vector_int &ninput_items, g
 
 		if (m_pFile_y)
 		{
-			fprintf(m_pFile_y, "%f %f %f %f\n", (float)m_sampleCounter/m_sampleRate, y, m_v_thr, vcorr);
+			fprintf(m_pFile_y, "%f %f %f %f\n", (float)m_sampleCounter/m_sampleRate, y, m_v_sig, m_id_accu);
 		}
 		m_sampleCounter++;
 		

gr-jay/lib/garage_impl.h

@@ -40,10 +40,11 @@ class garage_impl : public garage
         float m_vmin;
         float m_vmax;
         float m_v_sig;
-        float m_v_sig_m;
+        float m_dc_corr;
-        float m_v_thr;
         float m_lag_accu;
-        int m_bit;
+        float m_id_accu;
+        int m_id_bit;
+        int m_bitZeroCross;
         float m_i;
         int m_gapDistance;
         int m_gapCounter;