diff --git a/DMRDMORX.cpp b/DMRDMORX.cpp
index d11957e..2c3bdef 100644
--- a/DMRDMORX.cpp
+++ b/DMRDMORX.cpp
@@ -88,7 +88,7 @@ bool CDMRDMORX::processSample(q15_t sample, uint16_t rssi)
   m_rssi[m_dataPtr] = rssi;
 
   m_bitBuffer[m_bitPtr] <<= 1;
-  if (sample < m_dcLevel)
+  if (sample < 0)
     m_bitBuffer[m_bitPtr] |= 0x01U;
 
   if (m_state == DMORXS_NONE) {
diff --git a/DMRSlotRX.cpp b/DMRSlotRX.cpp
index 377aa41..0d34560 100644
--- a/DMRSlotRX.cpp
+++ b/DMRSlotRX.cpp
@@ -104,7 +104,7 @@ bool CDMRSlotRX::processSample(q15_t sample, uint16_t rssi)
   m_rssi[m_dataPtr] = rssi;
   
   m_bitBuffer[m_bitPtr] <<= 1;
-  if (sample < m_dcLevel)
+  if (sample < 0)
     m_bitBuffer[m_bitPtr] |= 0x01U;
 
   if (m_state == DMRRXS_NONE) {
diff --git a/DStarRX.cpp b/DStarRX.cpp
index 4159c0d..103176b 100644
--- a/DStarRX.cpp
+++ b/DStarRX.cpp
@@ -279,7 +279,7 @@ void CDStarRX::samples(const q15_t* samples, const uint16_t* rssi, uint8_t lengt
     m_rssiAccum += rssi[i];
     m_rssiCount++;
 
-    bool bit = samples[i] < m_dcLevel;
+    bool bit = samples[i] < 0;
 
     if (bit != m_prev) {
       if (m_pll < (PLLMAX / 2U))
diff --git a/Globals.h b/Globals.h
index e99022f..7b80226 100644
--- a/Globals.h
+++ b/Globals.h
@@ -93,8 +93,6 @@ extern bool m_duplex;
 extern bool m_tx;
 extern bool m_dcd;
 
-extern q15_t m_dcLevel;
-
 extern CSerialPort serial;
 extern CIO io;
 
diff --git a/IO.cpp b/IO.cpp
index f47542d..8f290e1 100644
--- a/IO.cpp
+++ b/IO.cpp
@@ -33,7 +33,7 @@ static q15_t   GAUSSIAN_0_5_FILTER[] = {8, 104, 760, 3158, 7421, 9866, 7421, 315
 const uint16_t GAUSSIAN_0_5_FILTER_LEN = 12U;
 
 // One symbol boxcar filter
-static q15_t   BOXCAR_FILTER[] = {3000, 3000, 3000, 3000, 3000, 0};
+static q15_t   BOXCAR_FILTER[] = {12000, 12000, 12000, 12000, 12000, 0};
 const uint16_t BOXCAR_FILTER_LEN = 6U;
 
 // Generated using [b, a] = butter(1, 0.001) in MATLAB
@@ -73,7 +73,7 @@ m_dcState()
   ::memset(m_rrcState,      0x00U, 70U * sizeof(q15_t));
   ::memset(m_gaussianState, 0x00U, 40U * sizeof(q15_t));
   ::memset(m_boxcarState,   0x00U, 30U * sizeof(q15_t));
-  ::memset(m_dcState,       0x00U, 4U * sizeof(q31_t));
+  ::memset(m_dcState,       0x00U,  4U * sizeof(q31_t));
 
   m_rrcFilter.numTaps = RRC_0_2_FILTER_LEN;
   m_rrcFilter.pState  = m_rrcState;
@@ -88,8 +88,8 @@ m_dcState()
   m_boxcarFilter.pCoeffs = BOXCAR_FILTER;
   
   m_dcFilter.numStages = DC_FILTER_STAGES;
-  m_dcFilter.pState  = m_dcState;
-  m_dcFilter.pCoeffs = DC_FILTER;
+  m_dcFilter.pState    = m_dcState;
+  m_dcFilter.pCoeffs   = DC_FILTER;
   m_dcFilter.postShift = 0;
 
   initInt();
@@ -171,17 +171,19 @@ void CIO::process()
       
     q31_t dcLevel = 0;
     q31_t dcVals[20];
-    q31_t intSamp[20];
-  
-    ::arm_q15_to_q31((q15_t*)samples, intSamp, RX_BLOCK_SIZE);
-    ::arm_biquad_cascade_df1_q31(&m_dcFilter, intSamp, dcVals, RX_BLOCK_SIZE);
+    q31_t q31Samples[20U];
+
+    ::arm_q15_to_q31(samples, q31Samples, RX_BLOCK_SIZE);
+    ::arm_biquad_cascade_df1_q31(&m_dcFilter, q31Samples, dcVals, RX_BLOCK_SIZE);
 
     for (uint8_t i = 0U; i < RX_BLOCK_SIZE; i++)
       dcLevel += dcVals[i];
-
     dcLevel /= RX_BLOCK_SIZE;
+
+    q15_t offset = q15_t(dcLevel >> 16);
     
-    m_dcLevel = q15_t(dcLevel >> 16);
+    for (uint8_t i = 0U; i < RX_BLOCK_SIZE; i++)
+      samples[i] -= offset;
 
     if (m_modemState == STATE_IDLE) {
       if (m_dstarEnable) {
diff --git a/IO.h b/IO.h
index aa718a5..07e6d2d 100644
--- a/IO.h
+++ b/IO.h
@@ -60,12 +60,12 @@ private:
   CSampleRB            m_txBuffer;
   CRSSIRB              m_rssiBuffer;
 
-  arm_fir_instance_q15 m_rrcFilter;
-  arm_fir_instance_q15 m_gaussianFilter;
-  arm_fir_instance_q15 m_boxcarFilter;
-  q15_t                m_rrcState[70U];           // NoTaps + BlockSize - 1, 42 + 20 - 1 plus some spare
-  q15_t                m_gaussianState[40U];      // NoTaps + BlockSize - 1, 12 + 20 - 1 plus some spare
-  q15_t                m_boxcarState[30U];        // NoTaps + BlockSize - 1, 6 + 20 - 1 plus some spare
+  arm_fir_instance_q15         m_rrcFilter;
+  arm_fir_instance_q15         m_gaussianFilter;
+  arm_fir_instance_q15         m_boxcarFilter;
+  q15_t                        m_rrcState[70U];           // NoTaps + BlockSize - 1, 42 + 20 - 1 plus some spare
+  q15_t                        m_gaussianState[40U];      // NoTaps + BlockSize - 1, 12 + 20 - 1 plus some spare
+  q15_t                        m_boxcarState[30U];        // NoTaps + BlockSize - 1, 6 + 20 - 1 plus some spare
   arm_biquad_casd_df1_inst_q31 m_dcFilter;
   q31_t                        m_dcState[4];
 
diff --git a/MMDVM.cpp b/MMDVM.cpp
index 4fda95c..6e2be23 100644
--- a/MMDVM.cpp
+++ b/MMDVM.cpp
@@ -36,8 +36,6 @@ bool m_duplex = true;
 bool m_tx  = false;
 bool m_dcd = false;
 
-q15_t m_dcLevel = 0;
-
 CDStarRX   dstarRX;
 CDStarTX   dstarTX;
 
diff --git a/P25RX.cpp b/P25RX.cpp
index f77bb7d..9228c5b 100644
--- a/P25RX.cpp
+++ b/P25RX.cpp
@@ -95,7 +95,7 @@ void CP25RX::samples(const q15_t* samples, uint16_t* rssi, uint8_t length)
     m_rssiCount++;
 
     m_bitBuffer[m_bitPtr] <<= 1;
-    if (sample < m_dcLevel)
+    if (sample < 0)
       m_bitBuffer[m_bitPtr] |= 0x01U;
 
     m_buffer[m_dataPtr] = sample;
diff --git a/YSFRX.cpp b/YSFRX.cpp
index e405634..88c6f83 100644
--- a/YSFRX.cpp
+++ b/YSFRX.cpp
@@ -91,7 +91,7 @@ void CYSFRX::samples(const q15_t* samples, uint16_t* rssi, uint8_t length)
     m_rssiCount++;
 
     m_bitBuffer[m_bitPtr] <<= 1;
-    if (sample < m_dcLevel)
+    if (sample < 0)
       m_bitBuffer[m_bitPtr] |= 0x01U;
 
     m_buffer[m_dataPtr] = sample;