diff --git a/AX25RX.cpp b/AX25RX.cpp
index 637bde0..2e2592b 100644
--- a/AX25RX.cpp
+++ b/AX25RX.cpp
@@ -39,22 +39,23 @@
  *      window='hann') * 32768,
  *  dtype=int)[10:-10]
  */
-const uint32_t FILTER_LEN = 132;
+
+const uint32_t FILTER_LEN = 130U;
+
 q15_t FILTER_COEFFS[] = {
-      0,     5,    12,    18,    21,   19,   11,    -2,   -15,   -25,
-    -27,   -21,   -11,    -3,    -5,  -19,  -43,   -69,   -83,   -73,
-    -35,    27,    98,   155,   180,  163,  109,    39,   -20,   -45,
-    -26,    23,    74,    89,    39,  -81, -247,  -407,  -501,  -480,
-   -334,   -92,   175,   388,   479,  429,  275,    99,     5,    68,
-    298,   626,   913,   994,   740,  115, -791, -1770, -2544, -2847,
-  -2509, -1527,   -76,  1518,  2875, 3653, 3653,  2875,  1518,   -76,
-  -1527, -2509, -2847, -2544, -1770, -791,  115,   740,   994,   913,
-    626,   298,    68,     5,    99,  275,  429,   479,   388,   175,
-    -92,  -334,  -480,  -501,  -407, -247,  -81,    39,    89,    74,
-     23,   -26,   -45,   -20,    39,  109,  163,   180,   155,    98,
-     27,   -35,   -73,   -83,   -69,  -43,  -19,    -5,    -3,   -11,
-    -21,   -27,   -25,   -15,    -2,   11,   19,    21,    18,    12,
-      5,     0
+      5,    12,    18,    21,   19,   11,    -2,   -15,   -25,   -27,
+    -21,   -11,    -3,    -5,  -19,  -43,   -69,   -83,   -73,   -35,
+     27,    98,   155,   180,  163,  109,    39,   -20,   -45,   -26,
+     23,    74,    89,    39,  -81, -247,  -407,  -501,  -480,  -334,
+    -92,   175,   388,   479,  429,  275,    99,     5,    68,   298,
+    626,   913,   994,   740,  115, -791, -1770, -2544, -2847, -2509,
+  -1527,   -76,  1518,  2875, 3653, 3653,  2875,  1518,   -76, -1527,
+  -2509, -2847, -2544, -1770, -791,  115,   740,   994,   913,   626,
+    298,    68,     5,    99,  275,  429,   479,   388,   175,   -92,
+   -334,  -480,  -501,  -407, -247,  -81,    39,    89,    74,    23,
+    -26,   -45,   -20,    39,  109,  163,   180,   155,    98,    27,
+    -35,   -73,   -83,   -69,  -43,  -19,    -5,    -3,   -11,   -21,
+    -27,   -25,   -15,    -2,   11,   19,    21,    18,    12,     5
 };
 
 CAX25RX::CAX25RX() :
diff --git a/AX25RX.h b/AX25RX.h
index 220d61d..d6e55c3 100644
--- a/AX25RX.h
+++ b/AX25RX.h
@@ -33,7 +33,7 @@ public:
 
 private:
   arm_fir_instance_q15 m_filter;
-  q15_t                m_state[160U];    // NoTaps + BlockSize - 1, 132 + 20 - 1 plus some spare
+  q15_t                m_state[160U];    // NoTaps + BlockSize - 1, 130 + 20 - 1 plus some spare
   CAX25Demodulator     m_demod1;
   CAX25Demodulator     m_demod2;
   CAX25Demodulator     m_demod3;