From 227018faa7ccf441dfa41a1f39f17299fc132321 Mon Sep 17 00:00:00 2001
From: Frank Mutter <frank@fradcode.de>
Date: Fri, 13 Jul 2018 19:25:38 +0200
Subject: [PATCH] changed sign

---
 c/goertzel/goertzel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/c/goertzel/goertzel.c b/c/goertzel/goertzel.c
index 19bfdf5..d13a874 100644
--- a/c/goertzel/goertzel.c
+++ b/c/goertzel/goertzel.c
@@ -29,7 +29,7 @@ float goertzel_mag(int numSamples,float TARGET_FREQUENCY,int SAMPLING_RATE, floa
 
     // calculate the real and imaginary results
     // scaling appropriately
-    real = (q2 - q1 * cosine) / scalingFactor;
+    real = (q1 * cosine - q2) / scalingFactor;
     imag = (q1 * sine) / scalingFactor;
 
     magnitude = sqrtf(real*real + imag*imag);
-- 
2.30.2