Added phase comment to goertzel

[mirrors/Programs.git] / c / goertzel / goertzel.c

diff --git a/c/goertzel/goertzel.c b/c/goertzel/goertzel.c
index 2cde63bfe2a015ef2ec398c99c3d69a1f958b3d5..85637ae43652097beb365abc5f943cdc8dc8a904 100644 (file)
--- a/c/goertzel/goertzel.c
+++ b/c/goertzel/goertzel.c
@@ -29,10 +29,11 @@ float goertzel_mag(int numSamples,float TARGET_FREQUENCY,int SAMPLING_RATE, floa
 
     // calculate the real and imaginary results
     // scaling appropriately
-    real = (q1 - q2 * cosine) / scalingFactor;
-    imag = (q2 * sine) / scalingFactor;
+    real = (q1 * cosine - q2) / scalingFactor;
+    imag = (q1 * sine) / scalingFactor;
 
     magnitude = sqrtf(real*real + imag*imag);
+    //phase = atan(imag/real)
     return magnitude;
 }