From 746d915bf9e16b120179a1771b0937c85a67ec81 Mon Sep 17 00:00:00 2001
From: Jonathan Naylor <naylorjs@yahoo.com>
Date: Thu, 11 Jun 2020 12:14:36 +0100
Subject: [PATCH] Rescale one of the filters for the MMDVM sample rate.

---
 AX25Demodulator.cpp | 11 ++++++-----
 AX25RX.cpp          | 29 ++++++++++++++++-------------
 2 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/AX25Demodulator.cpp b/AX25Demodulator.cpp
index 4e635af..692a63a 100644
--- a/AX25Demodulator.cpp
+++ b/AX25Demodulator.cpp
@@ -122,6 +122,7 @@ bool CAX25Demodulator::process(const q15_t* samples, uint8_t length, CAX25Frame&
       } else {
         result = HDLC(NRZI(bit));
         if (result) {
+          // Copy the frame data.
           ::memcpy(frame.m_data, m_frame.m_data, AX25_MAX_PACKET_LEN);
           frame.m_length = frame.m_length;
           frame.m_fcs    = m_frame.m_fcs;
@@ -187,8 +188,6 @@ bool CAX25Demodulator::PLL(bool input)
 
 bool CAX25Demodulator::HDLC(bool b)
 {
-  bool result = false;
-
   if (m_hdlcOnes == 5U) {
     if (b) {
       // flag byte
@@ -197,7 +196,7 @@ bool CAX25Demodulator::HDLC(bool b)
       // bit stuffing...
       m_hdlcFlag = false;
       m_hdlcOnes = 0U;
-      return result;
+      return false;
     }
   }
 
@@ -211,9 +210,11 @@ bool CAX25Demodulator::HDLC(bool b)
     m_hdlcOnes = 0U;
 
   if (m_hdlcFlag) {
+    bool result = false;
+
     switch (m_hdlcBuffer) {
       case 0x7E:
-        if (m_frame.m_length > 0U) {
+        if (m_frame.m_length > 2U) {
           result = m_frame.checkCRC();
           if (!result)
             m_frame.m_length = 0U;
@@ -262,6 +263,6 @@ bool CAX25Demodulator::HDLC(bool b)
       break;
   }
 
-  return result;
+  return false;
 }
 
diff --git a/AX25RX.cpp b/AX25RX.cpp
index de20709..c138333 100644
--- a/AX25RX.cpp
+++ b/AX25RX.cpp
@@ -60,7 +60,7 @@ float32_t dB3[] = {
 
 /*
  * Generated with Scipy Filter, 152 coefficients, 1100-2300Hz bandpass,
- * Hann window, starting and ending 0 value coefficients removed.
+ * Hann window.
  *
  * np.array(
  *  firwin2(152,
@@ -79,19 +79,22 @@ float32_t dB3[] = {
  */
 const uint32_t FILTER_LEN = 132U;
 
-// XXX This is for the wrong sample rate
 q15_t FILTER_COEFFS[] = {
-    4,     0,    -5,   -10,   -13,   -12,    -9,    -4,    -2,    -4,   -12,   -26,
-  -41,   -52,   -51,   -35,    -3,    39,    83,   117,   131,   118,    83,    36,
-   -6,   -32,   -30,    -3,    36,    67,    66,    19,   -74,  -199,  -323,  -408,
- -421,  -344,  -187,    17,   218,   364,   417,   369,   247,   106,    14,    26,
-  166,   407,   676,   865,   866,   605,    68,  -675, -1484, -2171, -2547, -2471,
--1895,  -882,   394,  1692,  2747,  3337,  3337,  2747,  1692,   394,  -882, -1895,
--2471, -2547, -2171, -1484,  -675,    68,   605,   866,   865,   676,   407,   166,
-   26,    14,   106,   247,   369,   417,   364,   218,    17,  -187,  -344,  -421,
- -408,  -323,  -199,   -74,    19,    66,    67,    36,    -3,   -30,   -32,    -6,
-   36,    83,   118,   131,   117,    83,    39,    -3,   -35,   -51,   -52,   -41,
-  -26,   -12,    -4,    -2,    -4,    -9,   -12,   -13,   -10,    -5,     0,     4};
+           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};
 
 CAX25RX::CAX25RX() :
 m_filter(),