- refined vthr calculation

- processing only if vthr > other threshold
- make lag accu leaky

git-svn-id: http://moon:8086/svn/matlab/trunk@101 801c6759-fa7c-4059-a304-17956f83a07c

garage_ip.m

@@ -24,15 +24,15 @@
 
 function [bits, x] = garage_ip (numSamplesPerSym)
 
-k_n = 0.00;	% NOise
+k_n = 0.01;	% NOise
 k_s = 1.0;		% Sym
 
-baud_init = 9600;
-fs = baud_init * numSamplesPerSym;
+baud_init = 2900;
+fs = baud_init * numSamplesPerSym
 
 numSyms = 100;
 numBursts = 3;
-numSymsPauseBetweenBurst = 50;
+numSymsPauseBetweenBurst = 25;
 
 syms = rand(numSyms, 1) > 0.5;
 
@@ -41,7 +41,7 @@ bit = 0;
 syms_m = manchester(syms);
 
 % Upconvert
-x = [];
+x = zeros(1, 2*numSymsPauseBetweenBurst*numSamplesPerSym);
 
 for k=1:numBursts
 	for n=1:2*numSyms,
@@ -51,10 +51,11 @@ for k=1:numBursts
 	end
 	x = [x zeros(1, numSymsPauseBetweenBurst*numSamplesPerSym)];
 end
+x = [x zeros(1, 20*numSymsPauseBetweenBurst*numSamplesPerSym)];
 
 % Channel
 [b,a] = butter(2, numSamplesPerSym/4*baud_init/fs);
-y = resample (x, 131, 121);
+y = resample (x, 3200, baud_init);
 %y = x;
 y = k_s*filter(b, a, y) + k_n*randn(1, length(y));
 
@@ -73,10 +74,12 @@ bits = [];
 v_min = 0;					% Threshold max
 v_max = 0;					% Threshold min
 hyst_thr = 0.5;				% Threshold hysteresis
-rho_thr = 1e-5;				% Threshold forgetting factor
-alpha_lead = 0.016;			% Symbol syncronizer loop filter lead 
+rho_thr = 1e-4;				% Threshold forgetting factor
+alpha_thr = 0.1;			% Min/Max update factor
+alpha_lead = 0.02;			% Symbol syncronizer loop filter lead 
 alpha_lag = 0.000008;		% Symbol syncronizer loop filter lag 
 lag_accu = 1;				% Symbol syncronizer loop filter
+loopThreshold = 0.1;		% Processing threshold
 ns = 1;						% Start sample source
 n = 1;						% Start sample sink
 err = 0;					% Error
@@ -87,14 +90,14 @@ while ns < N
 	ys = (1-mu).*y(is) + mu.*y(is+1);
 
 	% Calculate threshold
-	v_thr = (v_max - v_min) / 2;
+	v_thr = (abs(v_max) - abs(v_min)) / 2;
 	if ys < v_min
-		v_min = ys;
+		v_min = (1-alpha_thr)*v_min + alpha_thr*ys;
 	elseif ys > v_max
-		v_max = ys;
+		v_max = (1-alpha_thr)*v_max + alpha_thr*ys;
 	end
 	v_min = v_min + rho_thr*(v_thr - v_min);
-	v_max = v_max - rho_thr*v_max;
+	v_max = v_max + rho_thr*(v_thr - v_max);
 
 	% Detect bit change
 	bitChg = 0;
@@ -114,7 +117,9 @@ while ns < N
 	if (bitChg)
 		err = -(count - fix(numSamplesPerSym/2));
 	end
-	
+	if v_thr < loopThreshold
+		err = 0;
+	end
 	% Sample bit at baud rate = fs/numSamplesPerSym
 	if count == 0
 		smp = [smp ys];
@@ -128,6 +133,7 @@ while ns < N
 	end
 	vcorr = alpha_lead*err + lag_accu;
 	lag_accu = lag_accu + alpha_lag*err;
+	lag_accu = lag_accu*(1-1e-8);
 	baud = vcorr*fs/numSamplesPerSym;
 	_err(n) = err;
 	_baud(n) = baud;
@@ -143,7 +149,7 @@ n = 1:length(_ys);
 
 % Plot
 subplot(3, 1, 1)
-plot(n, _ys, smp_n, smp, 'ro', n, _v_tr, 'y'); grid;
+plot(n, _ys, n, _v_tr, 'y', smp_n, smp, 'ro'); grid;
 subplot(3, 1, 2)
 plot(n, _err); grid;
 subplot(3, 1, 3)