implement frequency correction feedback loop

csdr/chain/dablin.py

@@ -1,21 +1,73 @@
 from csdr.chain.demodulator import BaseDemodulatorChain, FixedIfSampleRateChain, FixedAudioRateChain, HdAudio
+from csdr.module import PickleModule
 from csdreti.modules import EtiDecoder
 from owrx.dab.dablin import DablinModule
-from pycsdr.modules import Downmix
+from pycsdr.modules import Downmix, Buffer, Shift
 from pycsdr.types import Format
+from typing import Optional
+from random import random
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class MetaProcessor(PickleModule):
+    def __init__(self, shifter: Shift):
+        self.shifter = shifter
+        self.shift = 0.0
+        self.coarse_increment = -32 / 2048000
+        self.fine_increment = - (1/3) / 2048000
+        super().__init__()
+
+    def process(self, data):
+        if "coarse_frequency_shift" in data:
+            value = int(data["coarse_frequency_shift"])
+            if value > 0:
+                self.shift += random() * self.coarse_increment
+            else:
+                self.shift -= random() * self.coarse_increment
+            logger.debug("coarse adjustment - new shift: %f", self.shift)
+            self.shifter.setRate(self.shift)
+        if "fine_frequency_shift" in data:
+            value = float(data["fine_frequency_shift"])
+            if abs(value) > 10:
+                self.shift += self.fine_increment * value
+                logger.debug("ffs: %f", value)
+                logger.debug("fine adjustment - new shift: %f", self.shift)
+                self.shifter.setRate(self.shift)
 
 
 class Dablin(BaseDemodulatorChain, FixedIfSampleRateChain, FixedAudioRateChain, HdAudio):
     def __init__(self):
+        shift = Shift(0)
+        decoder = EtiDecoder()
+
+        metaBuffer = Buffer(Format.CHAR)
+        decoder.setMetaWriter(metaBuffer)
+        self.processor = MetaProcessor(shift)
+        self.processor.setReader(metaBuffer.getReader())
+        self.processor.setWriter(Buffer(Format.CHAR))
+
         workers = [
-            EtiDecoder(),
+            shift,
+            decoder,
             DablinModule(),
             Downmix(Format.FLOAT),
         ]
         super().__init__(workers)
 
+    def _connect(self, w1, w2, buffer: Optional[Buffer] = None) -> None:
+        if isinstance(w2, EtiDecoder):
+            # eti decoder needs big chunks of data
+            buffer = Buffer(w1.getOutputFormat(), size=1048576)
+        super()._connect(w1, w2, buffer)
+
     def getFixedIfSampleRate(self) -> int:
         return 2048000
 
     def getFixedAudioRate(self) -> int:
         return 48000
+
+    def stop(self):
+        self.processor.stop()

owrx/dsp.py

@@ -40,7 +40,7 @@ class ClientDemodulatorChain(Chain):
         self.hdOutputRate = hdOutputRate
         self.secondaryDspEventReceiver = secondaryDspEventReceiver
         self.selector = Selector(sampleRate, outputRate)
-        self.selectorBuffer = Buffer(Format.COMPLEX_FLOAT, size=524288)
+        self.selectorBuffer = Buffer(Format.COMPLEX_FLOAT)
         self.audioBuffer = None
         self.demodulator = demod
         self.secondaryDemodulator = None