From b165e025d964ca71df4a8764ed8132673bc0c510 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Mon, 21 Nov 2016 16:48:10 +1100
Subject: [PATCH] Filter: added new constructor for 1p filter

allow both sample rate and cutoff to be specified in constructor
---
 libraries/Filter/LowPassFilter.cpp | 18 ++++++++++++------
 libraries/Filter/LowPassFilter.h   |  1 +
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/libraries/Filter/LowPassFilter.cpp b/libraries/Filter/LowPassFilter.cpp
index be14b7148b..282ca5a3bf 100644
--- a/libraries/Filter/LowPassFilter.cpp
+++ b/libraries/Filter/LowPassFilter.cpp
@@ -61,14 +61,20 @@ void DigitalLPF<T>::reset(T value) {
 ////////////////////////////////////////////////////////////////////////////////////////////
 // LowPassFilter
 ////////////////////////////////////////////////////////////////////////////////////////////
+
+// constructors
 template <class T>
-LowPassFilter<T>::LowPassFilter() : _cutoff_freq(0.0f) { 
-  
-}
-// constructor
+LowPassFilter<T>::LowPassFilter() :
+    _cutoff_freq(0.0f) {}
+
 template <class T>
-LowPassFilter<T>::LowPassFilter(float cutoff_freq) : _cutoff_freq(cutoff_freq) { 
-  
+LowPassFilter<T>::LowPassFilter(float cutoff_freq) :
+    _cutoff_freq(cutoff_freq) {}
+
+template <class T>
+LowPassFilter<T>::LowPassFilter(float sample_freq, float cutoff_freq)
+{
+    set_cutoff_frequency(sample_freq, cutoff_freq);
 }
 
 // change parameters
diff --git a/libraries/Filter/LowPassFilter.h b/libraries/Filter/LowPassFilter.h
index 6781e28b67..1ff19a3875 100644
--- a/libraries/Filter/LowPassFilter.h
+++ b/libraries/Filter/LowPassFilter.h
@@ -73,6 +73,7 @@ class LowPassFilter {
 public:
     LowPassFilter();
     LowPassFilter(float cutoff_freq);
+    LowPassFilter(float sample_freq, float cutoff_freq);
 
     // change parameters
     void set_cutoff_frequency(float cutoff_freq);