first steps at rewiring the dsp stuff

csdr/chain/selector.py

@@ -0,0 +1,126 @@
+from csdr.chain import Chain
+from pycsdr.modules import Shift, FirDecimate, Bandpass, Squelch, FractionalDecimator, Writer
+from pycsdr.types import Format
+import math
+
+
+class Decimator(Chain):
+    def __init__(self, inputRate: int, outputRate: int):
+        if outputRate > inputRate:
+            raise ValueError("impossible decimation: cannot upsample {} to {}".format(inputRate, outputRate))
+        self.inputRate = inputRate
+        self.outputRate = outputRate
+
+        decimation, fraction = self._getDecimation(outputRate)
+        transition = 0.15 * (outputRate / float(self.inputRate))
+        # 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.
+        cutoff = 0.5 * decimation / (self.inputRate / outputRate)
+
+        workers = [
+            FirDecimate(decimation, transition, cutoff),
+        ]
+
+        if fraction != 1.0:
+            workers += [FractionalDecimator(Format.COMPLEX_FLOAT, fraction)]
+
+        super().__init__(workers)
+
+    def _getDecimation(self, outputRate: int) -> (int, float):
+        d = self.inputRate / outputRate
+        dInt = int(d)
+        dFloat = float(self.inputRate / dInt) / outputRate
+        return dInt, dFloat
+
+    def _reconfigure(self):
+        decimation, fraction = self._getDecimation(self.outputRate)
+        transition = 0.15 * (self.outputRate / float(self.inputRate))
+        cutoff = 0.5 * decimation / (self.inputRate / self.outputRate)
+        self.replace(0, FirDecimate(decimation, transition, cutoff))
+        index = self.indexOf(lambda x: isinstance(x, FractionalDecimator))
+        if fraction != 1.0:
+            decimator = FractionalDecimator(Format.COMPLEX_FLOAT, fraction)
+            if index >= 0:
+                self.replace(index, decimator)
+            else:
+                self.append(decimator)
+        elif index >= 0:
+            self.remove(index)
+
+    def setOutputRate(self, outputRate: int) -> None:
+        if outputRate == self.outputRate:
+            return
+        self.outputRate = outputRate
+        self._reconfigure()
+
+    def setInputRate(self, inputRate: int) -> None:
+        if inputRate == self.inputRate:
+            return
+        self.inputRate = inputRate
+        self._reconfigure()
+
+
+class Selector(Chain):
+    def __init__(self, inputRate: int, outputRate: int, shiftRate: float):
+        self.outputRate = outputRate
+
+        self.shift = Shift(shiftRate)
+
+        self.decimation = Decimator(inputRate, outputRate)
+
+        self.bandpass = self._buildBandpass()
+        self.bandpassCutoffs = None
+        self.setBandpass(-4000, 4000)
+
+        self.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(outputRate / (self.readings_per_second * 1024)))
+
+        workers = [self.shift, self.decimation, self.bandpass, self.squelch]
+
+        super().__init__(workers)
+
+    def _buildBandpass(self) -> Bandpass:
+        bp_transition = 320.0 / self.outputRate
+        return Bandpass(transition=bp_transition, use_fft=True)
+
+    def setShiftRate(self, rate: float) -> None:
+        self.shift.setRate(rate)
+
+    def _convertToLinear(self, db: float) -> float:
+        return float(math.pow(10, db / 10))
+
+    def setSquelchLevel(self, level: float) -> None:
+        self.squelch.setSquelchLevel(self._convertToLinear(level))
+
+    def setBandpass(self, lowCut: float, highCut: float) -> None:
+        self.bandpassCutoffs = [lowCut, highCut]
+        scaled = [x / self.outputRate for x in self.bandpassCutoffs]
+        self.bandpass.setBandpass(*scaled)
+
+    def setLowCut(self, lowCut: float) -> None:
+        self.bandpassCutoffs[0] = lowCut
+        self.setBandpass(*self.bandpassCutoffs)
+
+    def setHighCut(self, highCut: float) -> None:
+        self.bandpassCutoffs[1] = highCut
+        self.setBandpass(*self.bandpassCutoffs)
+
+    def setPowerWriter(self, writer: Writer) -> None:
+        self.squelch.setPowerWriter(writer)
+
+    def setOutputRate(self, outputRate: int) -> None:
+        if outputRate == self.outputRate:
+            return
+        self.outputRate = outputRate
+
+        self.decimation.setOutputRate(outputRate)
+        self.squelch.setReportInterval(int(outputRate / (self.readings_per_second * 1024)))
+        self.bandpass = self._buildBandpass()
+        self.setBandpass(*self.bandpassCutoffs)
+        self.replace(2, self.bandpass)
+
+    def setInputRate(self, inputRate: int) -> None:
+        self.decimation.setInputRate(inputRate)