From 9e9ae9521902c65ad563642fc021ecc86ee06212 Mon Sep 17 00:00:00 2001
From: arancormonk <180709949+arancormonk@users.noreply.github.com>
Date: Wed, 3 Sep 2025 20:33:04 -0500
Subject: [PATCH] rtl_sdr_fm: use fast atan2 discriminator for analog mode to
 reduce quantization noise

---
 src/rtl_sdr_fm.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/rtl_sdr_fm.cpp b/src/rtl_sdr_fm.cpp
index bd245c6..a0c107e 100644
--- a/src/rtl_sdr_fm.cpp
+++ b/src/rtl_sdr_fm.cpp
@@ -1693,10 +1693,10 @@ void demod_init_analog(struct demod_state *s)
 	s->terminate_on_squelch = 0;
 	s->squelch_hits = 11;
 	s->downsample_passes = 1; //
-	s->comp_fir_size = 0;
+	s->comp_fir_size = 9;
 	s->prev_index = 0;
 	s->post_downsample = 1;  //1 -- once this works, default = 4 -- doesn't work on the official rtl-sdr source code either
-	s->custom_atan = 2;
+	s->custom_atan = 1;
 	s->deemph = 1; //
 	s->rate_out2 = rtl_bandwidth;  // -1 flag for disabled -- this enables low_pass_real, seems to work okay
 	s->mode_demod = &fm_demod;