first steps at rewiring the dsp stuff

csdr/chain/demodulator.py

@@ -1,65 +1,12 @@
 from csdr.chain import Chain
-from pycsdr.modules import Shift, FirDecimate, Bandpass, Squelch, FractionalDecimator, Writer
-from pycsdr.types import Format
-from csdr.chain.digiham import Dmr
 
 
-class DemodulatorChain(Chain):
-    def __init__(self, samp_rate: int, audioRate: int, shiftRate: float, demodulator: Chain):
-        self.demodulator = demodulator
+class BaseDemodulatorChain(Chain):
+    def getFixedIfSampleRate(self):
+        return None
 
-        self.shift = Shift(shiftRate)
+    def getFixedAudioRate(self):
+        return None
 
-        decimation, fraction = self._getDecimation(samp_rate, audioRate)
-        if_samp_rate = samp_rate / decimation
-        transition = 0.15 * (if_samp_rate / float(samp_rate))
-        # set the cutoff on the fist decimation stage lower so that the resulting output
-        # is already prepared for the second (fractional) decimation stage.
-        # this spares us a second filter.
-        self.decimation = FirDecimate(decimation, transition, 0.5 * decimation / (samp_rate / audioRate))
-
-        bp_transition = 320.0 / audioRate
-        self.bandpass = Bandpass(transition=bp_transition, use_fft=True)
-
-        readings_per_second = 4
-        # s-meter readings are available every 1024 samples
-        # the reporting interval is measured in those 1024-sample blocks
-        self.squelch = Squelch(5, int(audioRate / (readings_per_second * 1024)))
-
-        workers = [self.shift, self.decimation]
-
-        if fraction != 1.0:
-            workers += [FractionalDecimator(Format.COMPLEX_FLOAT, fraction)]
-
-        workers += [self.bandpass, self.squelch, demodulator]
-
-        super().__init__(*workers)
-
-    def setShiftRate(self, rate: float):
-        self.shift.setRate(rate)
-
-    def setSquelchLevel(self, level: float):
-        self.squelch.setSquelchLevel(level)
-
-    def setBandpass(self, low_cut: float, high_cut: float):
-        self.bandpass.setBandpass(low_cut, high_cut)
-
-    def setPowerWriter(self, writer: Writer):
-        self.squelch.setPowerWriter(writer)
-
-    def setMetaWriter(self, writer: Writer):
-        self.demodulator.setMetaWriter(writer)
-
-    def setDmrFilter(self, filter: int) -> None:
-        if isinstance(self.demodulator, Dmr):
-            self.demodulator.setSlotFilter(filter)
-
-    def _getDecimation(self, input_rate, output_rate):
-        if output_rate <= 0:
-            raise ValueError("invalid output rate: {rate}".format(rate=output_rate))
-        decimation = 1
-        target_rate = output_rate
-        while input_rate / (decimation + 1) >= target_rate:
-            decimation += 1
-        fraction = float(input_rate / decimation) / output_rate
-        return decimation, fraction
+    def supportsSquelch(self):
+        return True