diff --git a/firmware/baseband/dsp_demodulate.cpp b/firmware/baseband/dsp_demodulate.cpp
index bc11e990c..42f04b01c 100644
--- a/firmware/baseband/dsp_demodulate.cpp
+++ b/firmware/baseband/dsp_demodulate.cpp
@@ -31,8 +31,8 @@ namespace dsp {
 namespace demodulate {
 
 buffer_s16_t AM::execute(
-	buffer_c16_t src,
-	buffer_s16_t dst
+	const buffer_c16_t& src,
+	const buffer_s16_t& dst
 ) {
 	/* Intermediate maximum value: 46341 (when input is -32768,-32768). */
 	/* Normalized to maximum 32767 for int16_t representation. */
@@ -78,8 +78,8 @@ static inline float angle_precise(const complex32_t t) {
 }
 
 buffer_s16_t FM::execute(
-	buffer_c16_t src,
-	buffer_s16_t dst
+	const buffer_c16_t& src,
+	const buffer_s16_t& dst
 ) {
 	auto z = z_;
 
diff --git a/firmware/baseband/dsp_demodulate.hpp b/firmware/baseband/dsp_demodulate.hpp
index 6e84fb8b3..0f1d4bf84 100644
--- a/firmware/baseband/dsp_demodulate.hpp
+++ b/firmware/baseband/dsp_demodulate.hpp
@@ -30,16 +30,16 @@ namespace demodulate {
 class AM {
 public:
 	buffer_s16_t execute(
-		buffer_c16_t src,
-		buffer_s16_t dst
+		const buffer_c16_t& src,
+		const buffer_s16_t& dst
 	);
 };
 
 class FM {
 public:
 	buffer_s16_t execute(
-		buffer_c16_t src,
-		buffer_s16_t dst
+		const buffer_c16_t& src,
+		const buffer_s16_t& dst
 	);
 
 	void configure(const float sampling_rate, const float deviation_hz) {