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- improved signal detection and thresholding

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- no lag accu update if no signal

git-svn-id: http://moon:8086/svn/matlab/trunk@114 801c6759-fa7c-4059-a304-17956f83a07c
This commit is contained in:
jens
2019-01-08 12:31:55 +00:00
parent 7293ec803f
commit 31467fc193
1 changed files with 30 additions and 10 deletions
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garage_ip.m
+30 -10
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@@ -24,8 +24,8 @@
function [bits] = garage_ip (varargin)
params = struct ('x', [], 'sampleRate', 48000, 'numSamplesPerSym', 16, 'loopFilterGain', 1.0, 'with_filter', 0, 'k_noise', 0.0);
units = struct ('x', '', 'sampleRate', '1/s', 'numSamplesPerSym', 'sps', 'loopFilterGain', '', 'with_filter', '', 'k_noise', '');
params = struct ('x', [], 'sampleRate', 48000, 'numSamplesPerSym', 16, 'loopFilterGain', 1.0, 'with_filter', 0, 'k_noise', 0.0, 'loopThreshold', 0.1);
units = struct ('x', '', 'sampleRate', '1/s', 'numSamplesPerSym', 'sps', 'loopFilterGain', '', 'with_filter', '', 'k_noise', '', 'loopThreshold', '');
% Parse parameters
names = fieldnames(params);
@@ -100,12 +100,10 @@ v_min = 0; % Threshold max
v_max = 0; % Threshold min
rho_thr = 0.999; % Threshold forgetting factor
alpha_thr = 0.002; % Min/Max update factor
k_leadLag = params.loopFilterGain; % Overall loopfilter gain (scales k_lead and k_lag)
k_lead = 0.1; % Symbol syncronizer loop filter lead
k_lag = 0.0001; % Symbol syncronizer loop filter lag
lag_accu = 0; % Symbol syncronizer loop filter
k_leak = 0.0; % Lag forgetting factor
loopThreshold = 0.02; % Processing threshold
rho_leak = 0.9999; % Lag forgetting factor
ns = 1; % Start sample source
n = 1; % Start sample sink
err = 0; % Error
@@ -117,6 +115,11 @@ k_id = 1/numSamplesPerSym;
id_accu = 0;
dc_corr = 0;
zbit = -1;
k_lead = k_lead * params.loopFilterGain;
k_lag = k_lag * params.loopFilterGain;
isSignal = 0;
while ns < N
% Get next interpolated sample
is = fix(ns);
@@ -136,8 +139,18 @@ while ns < N
dc_corr = dc_corr + alpha_thr*(v_max + v_min);
% Signal detection
v_sig = (1-alpha_sig)*v_sig + alpha_sig*ys*ys;
isSignal = v_sig >= loopThreshold;
yd = abs(ys)-v_max;
v_sig = (1-alpha_sig)*v_sig + alpha_sig*yd*yd;
if isSignal == 0
if v_sig < params.loopThreshold
isSignal = 1;
end
else
if v_sig > 1.2*params.loopThreshold
isSignal = 0;
end
end
% Integrate and dump
id_accu = id_accu + k_id*ys;
@@ -184,9 +197,16 @@ while ns < N
else
count = countReload;
end
vcorr = k_leadLag*k_lead*err + lag_accu;
lag_accu = lag_accu + k_leadLag*k_lag*err;
lag_accu = lag_accu * (1-k_leak);
vcorr = k_lead*err + lag_accu;
lag_accu = lag_accu * rho_leak;
if isSignal
if lag_accu > -0.2 && lag_accu < 0.2
lag_accu = lag_accu + k_lag*err;
end
else
lag_accu = 0;
end
baud = fs/((1+lag_accu)*numSamplesPerSym);
k_id = 1/((1+lag_accu)*numSamplesPerSym);
_err(n) = err;