From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Sun, 11 Oct 2015 10:39:26 +0000 (+0200)
Subject: Update loop filter to take into account ratio; based on email from Fons Adriaensen.
X-Git-Tag: 1.0.0~252
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=1dfcb58d4eda2c5c3ca8283f1467b6100460daed;p=nageru

Update loop filter to take into account ratio; based on email from Fons Adriaensen.
---

diff --git a/resampler.cpp b/resampler.cpp
index 5731465..efa0f17 100644
--- a/resampler.cpp
+++ b/resampler.cpp
@@ -90,14 +90,11 @@ void Resampler::get_output_samples(double pts, float *samples, ssize_t num_sampl
 	// The loop bandwidth starts at 1.0 Hz, then goes down to 0.05 Hz after four seconds.
 	double loop_bandwidth_hz = (k_a0 < 4 * freq_in) ? 1.0 : 0.05;
 
-	// Set first filter much wider than the first one (20x as wide).
-	double w = (2.0 * M_PI) * 20.0 * loop_bandwidth_hz * num_samples / freq_out;
-	double w0 = 1.0 - exp(-w);
-
-	// Set second filter.
-	w = (2.0 * M_PI) * loop_bandwidth_hz * ratio / freq_out;
-	double w1 = w * 1.6;
-	double w2 = w * num_samples / 1.6;
+	// Set filters. The first filter much wider than the first one (20x as wide).
+	double w = (2.0 * M_PI) * loop_bandwidth_hz * num_samples / freq_out;
+	double w0 = 1.0 - exp(-20.0 * w);
+	double w1 = w * 1.5 / num_samples / ratio;
+	double w2 = w / 1.5;
 
 	// Filter <err> through the loop filter to find the correction ratio.
 	z1 += w0 * (w1 * err - z1);