diff --git a/DStarRX.cpp b/DStarRX.cpp
index b7fea0c..4def275 100644
--- a/DStarRX.cpp
+++ b/DStarRX.cpp
@@ -279,7 +279,7 @@ void CDStarRX::reset()
   m_rssiCount    = 0U;
 }
 
-void CDStarRX::samples(q15_t* samples, const uint16_t* rssi, uint8_t length)
+void CDStarRX::samples(const q15_t* samples, const uint16_t* rssi, uint8_t length)
 {
   for (uint16_t i = 0U; i < length; i++) {
     m_rssiAccum += rssi[i];
diff --git a/DStarRX.h b/DStarRX.h
index 4223974..50ddf79 100644
--- a/DStarRX.h
+++ b/DStarRX.h
@@ -32,7 +32,7 @@ class CDStarRX {
 public:
   CDStarRX();
 
-  void samples(q15_t* samples, const uint16_t* rssi, uint8_t length);
+  void samples(const q15_t* samples, const uint16_t* rssi, uint8_t length);
 
   void reset();
 
diff --git a/P25RX.cpp b/P25RX.cpp
index 6b4cfd4..9228c5b 100644
--- a/P25RX.cpp
+++ b/P25RX.cpp
@@ -86,7 +86,7 @@ void CP25RX::reset()
   m_rssiCount     = 0U;
 }
 
-void CP25RX::samples(q15_t* samples, uint16_t* rssi, uint8_t length)
+void CP25RX::samples(const q15_t* samples, uint16_t* rssi, uint8_t length)
 {
   for (uint8_t i = 0U; i < length; i++) {
     q15_t sample = samples[i];
diff --git a/P25RX.h b/P25RX.h
index 48af4f9..0bdf3c5 100644
--- a/P25RX.h
+++ b/P25RX.h
@@ -32,7 +32,7 @@ class CP25RX {
 public:
   CP25RX();
 
-  void samples(q15_t* samples, uint16_t* rssi, uint8_t length);
+  void samples(const q15_t* samples, uint16_t* rssi, uint8_t length);
 
   void reset();
 
diff --git a/YSFRX.cpp b/YSFRX.cpp
index 3b156af..88c6f83 100644
--- a/YSFRX.cpp
+++ b/YSFRX.cpp
@@ -82,7 +82,7 @@ void CYSFRX::reset()
   m_rssiCount    = 0U;
 }
 
-void CYSFRX::samples(q15_t* samples, uint16_t* rssi, uint8_t length)
+void CYSFRX::samples(const q15_t* samples, uint16_t* rssi, uint8_t length)
 {
   for (uint8_t i = 0U; i < length; i++) {
     q15_t sample = samples[i];
diff --git a/YSFRX.h b/YSFRX.h
index a4aea4a..556280a 100644
--- a/YSFRX.h
+++ b/YSFRX.h
@@ -31,7 +31,7 @@ class CYSFRX {
 public:
   CYSFRX();
 
-  void samples(q15_t* samples, uint16_t* rssi, uint8_t length);
+  void samples(const q15_t* samples, uint16_t* rssi, uint8_t length);
 
   void reset();