Only require 8 preamble bits instead of 20

This matches the behaviour of a real receiver.
argilo · Jan 16, 2024 · b6fb676 · b6fb676
1 parent f98c322
commit b6fb676
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Showing 3 changed files with 34 additions and 50 deletions.
diff --git a/secplus_rx.grc b/secplus_rx.grc
@@ -749,19 +749,19 @@ blocks:
       \ if rising else 1)\n            self.buffer.append(0 if rising else 1)\n  \
       \      else:\n            self.buffer = []\n\n    def process_buffer(self, current_sample):\n\
       \        manchester = \"\".join(str(b) for b in self.buffer)\n        start\
-      \ = manchester.find(\"1010101010101010101010101010101001010101\")\n        if\
-      \ start == -1:\n            return\n\n        if manchester[start+44:start+48]\
-      \ == \"1010\":\n            packet_length = 40\n        elif manchester[start+44:start+48]\
-      \ == \"1001\":\n            packet_length = 64\n        else:\n            return\n\
-      \n        manchester = manchester[start:start+44+(packet_length*2)]\n      \
-      \  baseband = []\n        for i in range(0, len(manchester), 2):\n         \
-      \   if manchester[i:i+2] == \"01\":\n                baseband.append(1)\n  \
-      \          elif manchester[i:i+2] == \"10\":\n                baseband.append(0)\n\
-      \            else:\n                return\n        packet = baseband[22:]\n\
-      \n        if baseband[20:22] == [0, 0]:\n            frame_id = 0\n        elif\
-      \ baseband[20:22] == [0, 1]:\n            frame_id = 1\n        else:\n    \
-      \        return\n\n        self.pair_time[frame_id] = current_sample\n\n   \
-      \     if self.pair[frame_id] == packet:\n            return\n\n        self.pair[frame_id]\
+      \ = manchester.find(\"1010101001010101\")\n        if start == -1:\n       \
+      \     return\n\n        if manchester[start+20:start+24] == \"1010\":\n    \
+      \        packet_length = 40\n        elif manchester[start+20:start+24] == \"\
+      1001\":\n            packet_length = 64\n        else:\n            return\n\
+      \n        manchester = manchester[start+16:start+20+(packet_length*2)]\n   \
+      \     baseband = []\n        for i in range(0, len(manchester), 2):\n      \
+      \      if manchester[i:i+2] == \"01\":\n                baseband.append(1)\n\
+      \            elif manchester[i:i+2] == \"10\":\n                baseband.append(0)\n\
+      \            else:\n                return\n        packet = baseband[2:]\n\n\
+      \        if baseband[0:2] == [0, 0]:\n            frame_id = 0\n        elif\
+      \ baseband[0:2] == [0, 1]:\n            frame_id = 1\n        else:\n      \
+      \      return\n\n        self.pair_time[frame_id] = current_sample\n\n     \
+      \   if self.pair[frame_id] == packet:\n            return\n\n        self.pair[frame_id]\
       \ = packet\n        \n        if (self.pair[frame_id ^ 1] is not None) and (len(self.pair[frame_id\
       \ ^ 1]) == packet_length):\n            if self.pair_time[frame_id] - self.pair_time[frame_id\
       \ ^ 1] < 0.35 * self.samp_rate:\n                try:\n                    rolling,\
@@ -797,4 +797,4 @@ connections:
 
 metadata:
   file_format: 1
-  grc_version: 3.10.5.0
+  grc_version: 3.10.9.2
diff --git a/secplus_rx.py b/secplus_rx.py
@@ -6,31 +6,19 @@
 #
 # GNU Radio Python Flow Graph
 # Title: Secplus Rx
-# GNU Radio version: 3.10.5.0
-
-from packaging.version import Version as StrictVersion
-
-if __name__ == '__main__':
-    import ctypes
-    import sys
-    if sys.platform.startswith('linux'):
-        try:
-            x11 = ctypes.cdll.LoadLibrary('libX11.so')
-            x11.XInitThreads()
-        except:
-            print("Warning: failed to XInitThreads()")
+# GNU Radio version: 3.10.9.2
 
 from PyQt5 import Qt
-from PyQt5.QtCore import QObject, pyqtSlot
 from gnuradio import qtgui
-from gnuradio.filter import firdes
-import sip
+from PyQt5.QtCore import QObject, pyqtSlot
 from gnuradio import blocks
 from gnuradio import filter
+from gnuradio.filter import firdes
 from gnuradio import gr
 from gnuradio.fft import window
 import sys
 import signal
+from PyQt5 import Qt
 from argparse import ArgumentParser
 from gnuradio.eng_arg import eng_float, intx
 from gnuradio import eng_notation
@@ -39,11 +27,10 @@
 import time
 import secplus_rx_secplus_decode as secplus_decode  # embedded python block
 import secplus_rx_secplus_v2_decode as secplus_v2_decode  # embedded python block
+import sip
 
 
 
-from gnuradio import qtgui
-
 class secplus_rx(gr.top_block, Qt.QWidget):
 
     def __init__(self):
@@ -53,8 +40,8 @@ def __init__(self):
         qtgui.util.check_set_qss()
         try:
             self.setWindowIcon(Qt.QIcon.fromTheme('gnuradio-grc'))
-        except:
-            pass
+        except BaseException as exc:
+            print(f"Qt GUI: Could not set Icon: {str(exc)}", file=sys.stderr)
         self.top_scroll_layout = Qt.QVBoxLayout()
         self.setLayout(self.top_scroll_layout)
         self.top_scroll = Qt.QScrollArea()
@@ -70,12 +57,11 @@ def __init__(self):
         self.settings = Qt.QSettings("GNU Radio", "secplus_rx")
 
         try:
-            if StrictVersion(Qt.qVersion()) < StrictVersion("5.0.0"):
-                self.restoreGeometry(self.settings.value("geometry").toByteArray())
-            else:
-                self.restoreGeometry(self.settings.value("geometry"))
-        except:
-            pass
+            geometry = self.settings.value("geometry")
+            if geometry:
+                self.restoreGeometry(geometry)
+        except BaseException as exc:
+            print(f"Qt GUI: Could not restore geometry: {str(exc)}", file=sys.stderr)
 
         ##################################################
         # Variables
@@ -89,6 +75,7 @@ def __init__(self):
         ##################################################
         # Blocks
         ##################################################
+
         # Create the options list
         self._freq_options = [310150000, 315150000, 390150000]
         # Create the labels list
@@ -265,9 +252,6 @@ def set_decim1(self, decim1):
 
 def main(top_block_cls=secplus_rx, options=None):
 
-    if StrictVersion("4.5.0") <= StrictVersion(Qt.qVersion()) < StrictVersion("5.0.0"):
-        style = gr.prefs().get_string('qtgui', 'style', 'raster')
-        Qt.QApplication.setGraphicsSystem(style)
     qapp = Qt.QApplication(sys.argv)
 
     tb = top_block_cls()

diff --git a/secplus_rx_secplus_v2_decode.py b/secplus_rx_secplus_v2_decode.py
@@ -73,18 +73,18 @@ def process_edge(self, rising, samples):
 
     def process_buffer(self, current_sample):
         manchester = "".join(str(b) for b in self.buffer)
-        start = manchester.find("1010101010101010101010101010101001010101")
+        start = manchester.find("1010101001010101")
         if start == -1:
             return
 
-        if manchester[start+44:start+48] == "1010":
+        if manchester[start+20:start+24] == "1010":
             packet_length = 40
-        elif manchester[start+44:start+48] == "1001":
+        elif manchester[start+20:start+24] == "1001":
             packet_length = 64
         else:
             return
 
-        manchester = manchester[start:start+44+(packet_length*2)]
+        manchester = manchester[start+16:start+20+(packet_length*2)]
         baseband = []
         for i in range(0, len(manchester), 2):
             if manchester[i:i+2] == "01":
@@ -93,11 +93,11 @@ def process_buffer(self, current_sample):
                 baseband.append(0)
             else:
                 return
-        packet = baseband[22:]
+        packet = baseband[2:]
 
-        if baseband[20:22] == [0, 0]:
+        if baseband[0:2] == [0, 0]:
             frame_id = 0
-        elif baseband[20:22] == [0, 1]:
+        elif baseband[0:2] == [0, 1]:
             frame_id = 1
         else:
             return