Adding FLdigi Navtex decoder, packaged into app by Franco.

csdr/chain/toolbox.py

@@ -1,6 +1,6 @@
-from csdr.chain.demodulator import ServiceDemodulator, DialFrequencyReceiver, FixedIfSampleRateChain
-from csdr.module.toolbox import Rtl433Module, MultimonModule, DumpHfdlModule, DumpVdl2Module, Dump1090Module, AcarsDecModule
-from pycsdr.modules import FmDemod, AudioResampler, Convert, Agc, Squelch
+from csdr.chain.demodulator import ServiceDemodulator, DialFrequencyReceiver, FixedIfSampleRateChain, SecondaryDemodulator, SecondarySelectorChain
+from csdr.module.toolbox import Rtl433Module, MultimonModule, DumpHfdlModule, DumpVdl2Module, Dump1090Module, AcarsDecModule, NavtexModule
+from pycsdr.modules import FmDemod, AudioResampler, Convert, Agc, Squelch, Shift, RealPart
 from pycsdr.types import Format
 from owrx.toolbox import TextParser, PageParser, SelCallParser, IsmParser
 from owrx.aircraft import HfdlParser, Vdl2Parser, AdsbParser, AcarsParser
@@ -188,3 +188,29 @@ class AcarsDemodulator(ServiceDemodulator, DialFrequencyReceiver):
 
     def setDialFrequency(self, frequency: int) -> None:
         self.parser.setDialFrequency(frequency)
+
+
+class NavtexDemodulator(SecondaryDemodulator, SecondarySelectorChain):
+    def __init__(self):
+        self.sampleRate = 12500
+        self.bandWidth = 340
+        self.offset = 1000
+        workers = [
+            Shift(float(self.offset - self.bandWidth/2) / self.sampleRate),
+            RealPart(),
+            Agc(Format.FLOAT),
+            Convert(Format.FLOAT, Format.SHORT),
+            NavtexModule(self.sampleRate),
+        ]
+        # Connect all the workers
+        super().__init__(workers)
+
+    def getBandwidth(self) -> float:
+        return self.bandWidth
+
+    def setSampleRate(self, sampleRate: int) -> None:
+        if sampleRate == self.sampleRate:
+            return
+        self.sampleRate = sampleRate
+        self.replace(0, Shift(float(self.offset - self.bandWidth/2) / self.sampleRate))
+        self.replace(4, NavtexModule(self.sampleRate))

csdr/module/toolbox.py

@@ -146,3 +146,18 @@ class AcarsDecModule(PopenModule):
         header[40:43] = bytes([0, 0xFF, 0xFF, 0xFF])
         # Send .WAV file header to the process
         self.process.stdin.write(header)
+
+
+class NavtexModule(PopenModule):
+    def __init__(self, sampleRate: int = 12000):
+        self.sampleRate = sampleRate
+        super().__init__()
+
+    def getCommand(self):
+        return [ "navtex_rx_from_file", str(self.sampleRate) ]
+
+    def getInputFormat(self) -> Format:
+        return Format.SHORT
+
+    def getOutputFormat(self) -> Format:
+        return Format.CHAR

owrx/dsp.py

@@ -663,6 +663,9 @@ class DspManager(SdrSourceEventClient, ClientDemodulatorSecondaryDspEventClient)
         elif mod == "sitorb":
             from csdr.chain.digimodes import SitorBDemodulator
             return SitorBDemodulator(100, 170)
+        elif mod == "navtex":
+            from csdr.chain.toolbox import NavtexDemodulator
+            return NavtexDemodulator()
         elif mod == "cwdecoder":
             from csdr.chain.digimodes import CwDemodulator
             return CwDemodulator(75.0)

owrx/modes.py

@@ -139,6 +139,7 @@ class Modes(object):
         DigitalMode("rtty450", "RTTY-450 (50N)", underlying=["usb", "lsb"]),
         DigitalMode("rtty85", "RTTY-85 (50N)", underlying=["usb", "lsb"]),
         DigitalMode("sitorb", "SITOR-B", underlying=["usb"]),
+        DigitalMode("navtex", "Navtex", underlying=["usb"]),
         WsjtMode("ft8", "FT8"),
         WsjtMode("ft4", "FT4"),
         WsjtMode("jt65", "JT65"),