From 0cb345ed5ccbe786d0a7e7e2de740c0a07b82770 Mon Sep 17 00:00:00 2001
From: ozpv <39195175+ozpv@users.noreply.github.com>
Date: Wed, 19 Aug 2026 21:34:09 -0500
Subject: sdram and ringmod effect

---
 Core/Src/Effects/ringmod.c | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)
 create mode 100755 Core/Src/Effects/ringmod.c

(limited to 'Core/Src/Effects/ringmod.c')

diff --git a/Core/Src/Effects/ringmod.c b/Core/Src/Effects/ringmod.c
new file mode 100755
index 0000000..732f68e
--- /dev/null
+++ b/Core/Src/Effects/ringmod.c
@@ -0,0 +1,37 @@
+/*
+ * ringmod.c
+ *
+ *  Created on: Aug 19, 2026
+ *      Author: ozpv
+ */
+
+#include "cs4272.h"
+#include "ringmod.h"
+#include <math.h>
+
+/* ring modulator */
+void ringmod(float *samples, size_t range_min, size_t range_max) {
+    static float lfo_phase = 0.0f;
+    static float carrier_phase = 0.0f;
+
+    const float frequency = 156.0f;
+    const float amount = 0.67f;
+    const float sample_rate = (float)SAMPLE_RATE;
+
+    float lfo_increment = M_TWOPI * (0.18f / sample_rate);
+
+    /* plus two because of */
+    for (size_t i = range_min; i < range_max; i += 2) {
+        lfo_phase = fmodf(lfo_phase + lfo_increment, M_TWOPI);
+
+        float lfo = sinf(lfo_phase);
+
+        float carrier_increment = M_TWOPI * ((frequency + lfo * (frequency * 3.0f * amount)) / sample_rate);
+
+        carrier_phase = fmodf(carrier_phase + carrier_increment, M_TWOPI);
+
+        float carrier = sinf(carrier_phase);
+
+        samples[i] = (samples[i] * 0.50f) + (samples[i] * carrier * 0.50f);
+    }
+}
-- 
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