From e2bf38ec1b8785365cb08155fa60a8af69f1e895 Mon Sep 17 00:00:00 2001
From: Konstantin Sharlaimov <konstantin.sharlaimov@gmail.com>
Date: Sun, 18 Sep 2016 20:10:59 +0300
Subject: [PATCH] Remove caching of dT value from pt1FilterApply4 (#614)

---
 src/main/common/filter.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/common/filter.c b/src/main/common/filter.c
index b689b25ef..2c5c6cd07 100644
--- a/src/main/common/filter.c
+++ b/src/main/common/filter.c
@@ -46,10 +46,10 @@ float pt1FilterApply4(pt1Filter_t *filter, float input, uint16_t f_cut, float dT
     // Pre calculate and store RC
     if (!filter->RC) {
         filter->RC = 1.0f / ( 2.0f * M_PIf * f_cut );
-        filter->dT = dT;
     }
 
-    filter->state = filter->state + filter->dT / (filter->RC + filter->dT) * (input - filter->state);
+    filter->dT = dT;    // cache latest dT for possible use in pt1FilterApply
+    filter->state = filter->state + dT / (filter->RC + dT) * (input - filter->state);
     return filter->state;
 }