From 1dfc16c0da3d5a207c8998a549dbfcb4b931a131 Mon Sep 17 00:00:00 2001
From: Jens Ahrensfeld <jens@jayfield.org>
Date: Tue, 21 May 2019 18:43:19 +0000
Subject: [PATCH] - improved noise estimation

git-svn-id: http://moon:8086/svn/software/trunk/projects/GnuRadio@435 b431acfa-c32f-4a4a-93f1-934dc6c82436
---
 matlab/peak_detect.m | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/matlab/peak_detect.m b/matlab/peak_detect.m
index 155d5bb..e3121ac 100644
--- a/matlab/peak_detect.m
+++ b/matlab/peak_detect.m
@@ -35,14 +35,14 @@ ks = 0.5;
 pa = 0.3;
 d_max = 30;
 
-am = 0.1;
+am = 0.02;
 as = 0.9;
 Ad = 20;
 Cm = 0;
 
 s = zeros(1, Nh);
 a = zeros(1, Nh);
-Xm = -40*ones(1, Nh);
+Xm = -120*ones(1, Nh);
 Xs = zeros(1, Nh);
 peak_count = zeros(1, Nh);
 
@@ -84,8 +84,17 @@ for k=1:numFrames
 	peak_count = gate_peak.*peak_count + gate_peak;
 	peak_cand = peak_count > 0;
 	% Update Xm at no-peak bins
-	Xm = (1-gate_upd) .* ((1-am)*Xm + am*X) + gate_upd.*Xm;
+	Xm = (1-gate_upd) .* ((1-am)*Xm + am*X) + gate_upd.*Xm*0.7;
 	
+	last = Xm(1);
+	for n=2:Nh,
+		if gate_upd(n) == 0
+			last = Xm(n);
+		else
+			Xm(n) = last;	
+		end
+	end
+ 
 	% Filtering
 	if 0
 		Nhf = 21;