first steps at rewiring the dsp stuff

csdr/__init__.py

@@ -37,10 +37,8 @@ from csdr.pipe import Pipe
 
 from pycsdr.modules import Buffer
 from pycsdr.types import Format
-from csdr.chain.demodulator import DemodulatorChain
+from csdr.chain.selector import Selector
-from csdr.chain.fm import NFm, WFm
+from csdr.chain.analog import Am, NFm, WFm, Ssb
-from csdr.chain.am import Am
-from csdr.chain.ssb import Ssb
 from csdr.chain.digiham import Dstar, Nxdn, Dmr, Ysf
 from csdr.chain.clientaudio import ClientAudioChain
 

csdr/chain/__init__.py

@@ -1,12 +1,13 @@
-from pycsdr.modules import Buffer, Writer
+from pycsdr.modules import Buffer
+from typing import Union, Callable
 
 
 class Chain:
-    def __init__(self, *workers):
+    def __init__(self, workers):
         self.reader = None
         self.writer = None
         self.clientReader = None
-        self.workers = list(workers)
+        self.workers = workers
         for i in range(1, len(self.workers)):
             self._connect(self.workers[i - 1], self.workers[i])
 
@@ -29,19 +30,17 @@ class Chain:
         if self.workers:
             self.workers[-1].setWriter(writer)
 
-    def stop(self):
+    def indexOf(self, search: Union[Callable, object]) -> int:
-        for w in self.workers:
+        def searchFn(x):
-            w.stop()
+            if callable(search):
-        if self.clientReader is not None:
+                return search(x)
-            # TODO should be covered by finalize
-            self.clientReader.stop()
-            self.clientReader = None
-
-    def getOutputFormat(self):
-        if self.workers:
-            return self.workers[-1].getOutputFormat()
             else:
-            raise BufferError("getOutputFormat on empty chain")
+                return x is search
+
+        try:
+            return next(i for i, v in enumerate(self.workers) if searchFn(v))
+        except StopIteration:
+            return -1
 
     def replace(self, index, newWorker):
         if index >= len(self.workers):
@@ -55,18 +54,59 @@ class Chain:
                 newWorker.setReader(self.reader)
         else:
             previousWorker = self.workers[index - 1]
-            buffer = Buffer(previousWorker.getOutputFormat())
+            self._connect(previousWorker, newWorker)
-            previousWorker.setWriter(buffer)
-            newWorker.setReader(buffer.getReader())
 
         if index == len(self.workers) - 1:
             if self.writer is not None:
                 newWorker.setWriter(self.writer)
         else:
             nextWorker = self.workers[index + 1]
-            buffer = Buffer(newWorker.getOutputFormat())
+            self._connect(newWorker, nextWorker)
-            newWorker.setWriter(buffer)
+
-            nextWorker.setReader(buffer.getReader())
+    def append(self, newWorker):
+        previousWorker = None
+        if self.workers:
+            previousWorker = self.workers[-1]
+
+        self.workers.append(newWorker)
+
+        if previousWorker:
+            self._connect(previousWorker, newWorker)
+        elif self.reader is not None:
+            newWorker.setReader(self.reader)
+
+        if self.writer is not None:
+            newWorker.setWriter(self.writer)
+
+    def remove(self, index):
+        removedWorker = self.workers[index]
+        self.workers.remove(removedWorker)
+        removedWorker.stop()
+
+        if index == 0:
+            if self.reader is not None:
+                self.workers[0].setReader(self.reader)
+        elif index == len(self.workers):
+            if self.writer is not None:
+                self.workers[-1].setWriter(self.writer)
+        else:
+            previousWorker = self.workers[index - 1]
+            nextWorker = self.workers[index]
+            self._connect(previousWorker, nextWorker)
+
+    def stop(self):
+        for w in self.workers:
+            w.stop()
+        if self.clientReader is not None:
+            # TODO should be covered by finalize
+            self.clientReader.stop()
+            self.clientReader = None
+
+    def getOutputFormat(self):
+        if self.workers:
+            return self.workers[-1].getOutputFormat()
+        else:
+            raise BufferError("getOutputFormat on empty chain")
 
     def pump(self, write):
         if self.writer is None:
@@ -87,4 +127,3 @@ class Chain:
                     write(data)
 
         return copy
-

csdr/chain/am.py

@@ -1,17 +0,0 @@
-from csdr.chain import Chain
-from pycsdr.modules import AmDemod, DcBlock, Agc, Convert
-from pycsdr.types import Format, AgcProfile
-
-
-class Am(Chain):
-    def __init__(self):
-        agc = Agc(Format.FLOAT)
-        agc.setProfile(AgcProfile.SLOW)
-        agc.setInitialGain(200)
-        workers = [
-            AmDemod(),
-            DcBlock(),
-            agc,
-        ]
-
-        super().__init__(*workers)

csdr/chain/analog.py

@@ -0,0 +1,54 @@
+from csdr.chain.demodulator import BaseDemodulatorChain
+from pycsdr.modules import AmDemod, DcBlock, FmDemod, Limit, NfmDeemphasis, Agc, WfmDeemphasis, FractionalDecimator, RealPart
+from pycsdr.types import Format, AgcProfile
+
+
+class Am(BaseDemodulatorChain):
+    def __init__(self):
+        agc = Agc(Format.FLOAT)
+        agc.setProfile(AgcProfile.SLOW)
+        agc.setInitialGain(200)
+        workers = [
+            AmDemod(),
+            DcBlock(),
+            agc,
+        ]
+
+        super().__init__(workers)
+
+
+class NFm(BaseDemodulatorChain):
+    def __init__(self, sampleRate: int):
+        agc = Agc(Format.FLOAT)
+        agc.setProfile(AgcProfile.SLOW)
+        agc.setMaxGain(3)
+        workers = [
+            FmDemod(),
+            Limit(),
+            NfmDeemphasis(sampleRate),
+            agc,
+        ]
+        super().__init__(workers)
+
+
+class WFm(BaseDemodulatorChain):
+    def __init__(self, sampleRate: int, tau: float):
+        workers = [
+            FmDemod(),
+            Limit(),
+            FractionalDecimator(Format.FLOAT, 200000.0 / sampleRate, prefilter=True),
+            WfmDeemphasis(sampleRate, tau),
+        ]
+        super().__init__(workers)
+
+    def getFixedIfSampleRate(self):
+        return 200000
+
+
+class Ssb(BaseDemodulatorChain):
+    def __init__(self):
+        workers = [
+            RealPart(),
+            Agc(Format.FLOAT),
+        ]
+        super().__init__(workers)

csdr/chain/clientaudio.py

@@ -6,6 +6,8 @@ from pycsdr.types import Format
 class ClientAudioChain(Chain):
     def __init__(self, format: Format, inputRate: int, clientRate: int, compression: str):
         workers = []
+        self.inputRate = inputRate
+        self.clientRate = clientRate
         if inputRate != clientRate:
             # we only have an audio resampler for float ATM so if we need to resample, we need to convert
             if format != Format.FLOAT:
@@ -15,4 +17,24 @@ class ClientAudioChain(Chain):
             workers += [Convert(format, Format.SHORT)]
         if compression == "adpcm":
             workers += [AdpcmEncoder(sync=True)]
-        super().__init__(*workers)
+        super().__init__(workers)
+
+    def setFormat(self, format: Format) -> None:
+        pass
+
+    def setInputRate(self, inputRate: int) -> None:
+        if inputRate == self.inputRate:
+            return
+
+    def setClientRate(self, clientRate: int) -> None:
+        if clientRate == self.clientRate:
+            return
+
+    def setAudioCompression(self, compression: str) -> None:
+        index = self.indexOf(lambda x: isinstance(x, AdpcmEncoder))
+        if compression == "adpcm":
+            if index < 0:
+                self.append(AdpcmEncoder(sync=True))
+        else:
+            if index >= 0:
+                self.remove(index)

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):
+class BaseDemodulatorChain(Chain):
-    def __init__(self, samp_rate: int, audioRate: int, shiftRate: float, demodulator: Chain):
+    def getFixedIfSampleRate(self):
-        self.demodulator = demodulator
+        return None
 
-        self.shift = Shift(shiftRate)
+    def getFixedAudioRate(self):
+        return None
 
-        decimation, fraction = self._getDecimation(samp_rate, audioRate)
+    def supportsSquelch(self):
-        if_samp_rate = samp_rate / decimation
+        return True
-        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

csdr/chain/digiham.py

@@ -1,11 +1,11 @@
-from csdr.chain import Chain
+from csdr.chain.demodulator import BaseDemodulatorChain
 from pycsdr.modules import FmDemod, Agc, Writer
 from pycsdr.types import Format
 from digiham.modules import DstarDecoder, DcBlock, FskDemodulator, GfskDemodulator, DigitalVoiceFilter, MbeSynthesizer, NarrowRrcFilter, NxdnDecoder, DmrDecoder, WideRrcFilter, YsfDecoder
 from digiham.ambe import Modes
 
 
-class DigihamChain(Chain):
+class DigihamChain(BaseDemodulatorChain):
     def __init__(self, fskDemodulator, decoder, mbeMode, filter=None, codecserver: str = ""):
         self.decoder = decoder
         if codecserver is None:
@@ -23,11 +23,20 @@ class DigihamChain(Chain):
             DigitalVoiceFilter(),
             agc
         ]
-        super().__init__(*workers)
+        super().__init__(workers)
+
+    def getFixedIfSampleRate(self):
+        return 48000
+
+    def getFixedAudioRate(self):
+        return 8000
 
     def setMetaWriter(self, writer: Writer):
         self.decoder.setMetaWriter(writer)
 
+    def supportsSquelch(self):
+        return False
+
 
 class Dstar(DigihamChain):
     def __init__(self, codecserver: str = ""):

csdr/chain/fft.py

@@ -7,7 +7,7 @@ class FftAverager(Chain):
         self.fftSize = fft_size
         self.fftAverages = fft_averages
         workers = [self._getWorker()]
-        super().__init__(*workers)
+        super().__init__(workers)
 
     def setFftAverages(self, fft_averages):
         if self.fftAverages == fft_averages:
@@ -46,7 +46,7 @@ class FftChain(Chain):
 
         self._updateParameters()
 
-        super().__init__(*workers)
+        super().__init__(workers)
 
     def _setBlockSize(self, fft_block_size):
         if self.blockSize == int(fft_block_size):

csdr/chain/fm.py

@@ -1,28 +0,0 @@
-from csdr.chain import Chain
-from pycsdr.modules import FmDemod, Limit, NfmDeemphasis, Agc, WfmDeemphasis, FractionalDecimator
-from pycsdr.types import Format, AgcProfile
-
-
-class NFm(Chain):
-    def __init__(self, sampleRate: int):
-        agc = Agc(Format.FLOAT)
-        agc.setProfile(AgcProfile.SLOW)
-        agc.setMaxGain(3)
-        workers = [
-            FmDemod(),
-            Limit(),
-            NfmDeemphasis(sampleRate),
-            agc,
-        ]
-        super().__init__(*workers)
-
-
-class WFm(Chain):
-    def __init__(self, sampleRate: int, tau: float):
-        workers = [
-            FmDemod(),
-            Limit(),
-            FractionalDecimator(Format.FLOAT, 200000.0 / sampleRate, prefilter=True),
-            WfmDeemphasis(sampleRate, tau),
-        ]
-        super().__init__(*workers)

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)

csdr/chain/ssb.py

@@ -1,12 +0,0 @@
-from csdr.chain import Chain
-from pycsdr.modules import RealPart, Agc, Convert
-from pycsdr.types import Format
-
-
-class Ssb(Chain):
-    def __init__(self):
-        workers = [
-            RealPart(),
-            Agc(Format.FLOAT),
-        ]
-        super().__init__(*workers)

owrx/connection.py

@@ -378,7 +378,8 @@ class OpenWebRxReceiverClient(OpenWebRxClient, SdrSourceEventClient):
 
     def write_s_meter_level(self, level):
         if isinstance(level, memoryview):
-            level, = struct.unpack('f', level)
+            # may contain more than one sample, so only take the last 4 bytes = 1 float
+            level, = struct.unpack('f', level[-4:])
         if not isinstance(level, float):
             logger.warning("s-meter value has unexpected type")
             return

owrx/dsp.py

@@ -9,7 +9,15 @@ from owrx.property.validators import OrValidator, RegexValidator, BoolValidator
 from owrx.modes import Modes
 from owrx.config.core import CoreConfig
 from csdr.output import Output
-from csdr import Dsp
+from csdr.chain import Chain
+from csdr.chain.demodulator import BaseDemodulatorChain
+from csdr.chain.selector import Selector
+from csdr.chain.clientaudio import ClientAudioChain
+from csdr.chain.analog import NFm, WFm, Am, Ssb
+from csdr.chain.digiham import Dmr, Dstar, Nxdn, Ysf
+from pycsdr.modules import Buffer, Writer
+from pycsdr.types import Format
+from typing import Union
 import threading
 import re
 
@@ -18,6 +26,82 @@ import logging
 logger = logging.getLogger(__name__)
 
 
+class ClientDemodulatorChain(Chain):
+    def __init__(self, demod: BaseDemodulatorChain, sampleRate: int, outputRate: int, audioCompression: str):
+        self.sampleRate = sampleRate
+        self.outputRate = outputRate
+        self.selector = Selector(sampleRate, outputRate, 0.0)
+        self.selector.setBandpass(-4000, 4000)
+        self.demodulator = demod
+        self.clientAudioChain = ClientAudioChain(Format.FLOAT, outputRate, outputRate, audioCompression)
+        super().__init__([self.selector, self.demodulator, self.clientAudioChain])
+
+    def setDemodulator(self, demodulator: BaseDemodulatorChain):
+        self.replace(1, demodulator)
+
+        if self.demodulator is not None:
+            self.demodulator.stop()
+
+        self.demodulator = demodulator
+
+        ifRate = self.demodulator.getFixedIfSampleRate()
+        if ifRate is not None:
+            self.selector.setOutputRate(ifRate)
+        else:
+            self.selector.setOutputRate(self.outputRate)
+
+        audioRate = self.demodulator.getFixedAudioRate()
+        if audioRate is not None:
+            self.clientAudioChain.setInputRate(audioRate)
+        else:
+            self.clientAudioChain.setInputRate(self.outputRate)
+
+        if not demodulator.supportsSquelch():
+            self.selector.setSquelchLevel(-150)
+
+        self.clientAudioChain.setFormat(demodulator.getOutputFormat())
+
+    def setLowCut(self, lowCut):
+        self.selector.setLowCut(lowCut)
+
+    def setHighCut(self, highCut):
+        self.selector.setHighCut(highCut)
+
+    def setBandpass(self, lowCut, highCut):
+        self.selector.setBandpass(lowCut, highCut)
+
+    def setFrequencyOffset(self, offset: int) -> None:
+        shift = -offset / self.sampleRate
+        self.selector.setShiftRate(shift)
+
+    def setAudioCompression(self, compression: str) -> None:
+        self.clientAudioChain.setAudioCompression(compression)
+
+    def setSquelchLevel(self, level: float) -> None:
+        if not self.demodulator.supportsSquelch():
+            return
+        self.selector.setSquelchLevel(level)
+
+    def setOutputRate(self, outputRate) -> None:
+        if outputRate == self.outputRate:
+            return
+
+        self.outputRate = outputRate
+        if self.demodulator.getFixedIfSampleRate() is None:
+            self.selector.setOutputRate(outputRate)
+        if self.demodulator.getFixedAudioRate() is None:
+            self.clientAudioChain.setClientRate(outputRate)
+
+    def setPowerWriter(self, writer: Writer) -> None:
+        self.selector.setPowerWriter(writer)
+
+    def setSampleRate(self, sampleRate: int) -> None:
+        if sampleRate == self.sampleRate:
+            return
+        self.sampleRate = sampleRate
+        self.selector.setInputRate(sampleRate)
+
+
 class ModulationValidator(OrValidator):
     """
     This validator only allows alphanumeric characters and numbers, but no spaces or special characters
@@ -75,18 +159,28 @@ class DspManager(Output, SdrSourceEventClient):
             ),
         )
 
-        self.dsp = Dsp(self)
+        # TODO wait for the rate to come from the client
-        self.dsp.nc_port = self.sdrSource.getPort()
+        if "output_rate" not in self.props:
+            self.props["output_rate"] = 12000
 
-        def set_low_cut(cut):
+        self.chain = ClientDemodulatorChain(
-            bpf = self.dsp.get_bpf()
+            self._getDemodulator("nfm"),
-            bpf[0] = cut
+            self.props["samp_rate"],
-            self.dsp.set_bpf(*bpf)
+            self.props["output_rate"],
+            self.props["audio_compression"]
+        )
 
-        def set_high_cut(cut):
+        # wire audio output
-            bpf = self.dsp.get_bpf()
+        buffer = Buffer(self.chain.getOutputFormat())
-            bpf[1] = cut
+        self.chain.setWriter(buffer)
-            self.dsp.set_bpf(*bpf)
+        reader = buffer.getReader()
+        self.send_output("audio", reader.read)
+
+        # wire power level output
+        buffer = Buffer(Format.FLOAT)
+        self.chain.setPowerWriter(buffer)
+        reader = buffer.getReader()
+        self.send_output("smeter", reader.read)
 
         def set_dial_freq(changes):
             if (
@@ -101,39 +195,46 @@ class DspManager(Output, SdrSourceEventClient):
                 parser.setDialFrequency(freq)
 
         if "start_mod" in self.props:
-            self.dsp.set_demodulator(self.props["start_mod"])
+            self.setDemodulator(self.props["start_mod"])
             mode = Modes.findByModulation(self.props["start_mod"])
 
             if mode and mode.bandpass:
-                self.dsp.set_bpf(mode.bandpass.low_cut, mode.bandpass.high_cut)
+                bpf = [mode.bandpass.low_cut, mode.bandpass.high_cut]
-            else:
+                self.chain.setBandpass(*bpf)
-                self.dsp.set_bpf(-4000, 4000)
 
         if "start_freq" in self.props and "center_freq" in self.props:
-            self.dsp.set_offset_freq(self.props["start_freq"] - self.props["center_freq"])
+            self.chain.setFrequencyOffset(self.props["start_freq"] - self.props["center_freq"])
         else:
-            self.dsp.set_offset_freq(0)
+            self.chain.setFrequencyOffset(0)
 
         self.subscriptions = [
-            self.props.wireProperty("audio_compression", self.dsp.set_audio_compression),
+            self.props.wireProperty("audio_compression", self.chain.setAudioCompression),
-            self.props.wireProperty("fft_compression", self.dsp.set_fft_compression),
+            # probably unused:
-            self.props.wireProperty("digimodes_fft_size", self.dsp.set_secondary_fft_size),
+            # self.props.wireProperty("fft_compression", self.dsp.set_fft_compression),
-            self.props.wireProperty("samp_rate", self.dsp.set_samp_rate),
+            # TODO
-            self.props.wireProperty("output_rate", self.dsp.set_output_rate),
+            # self.props.wireProperty("digimodes_fft_size", self.dsp.set_secondary_fft_size),
-            self.props.wireProperty("hd_output_rate", self.dsp.set_hd_output_rate),
+            self.props.wireProperty("samp_rate", self.chain.setSampleRate),
-            self.props.wireProperty("offset_freq", self.dsp.set_offset_freq),
+            self.props.wireProperty("output_rate", self.chain.setOutputRate),
-            self.props.wireProperty("center_freq", self.dsp.set_center_freq),
+            # TODO
-            self.props.wireProperty("squelch_level", self.dsp.set_squelch_level),
+            # self.props.wireProperty("hd_output_rate", self.dsp.set_hd_output_rate),
-            self.props.wireProperty("low_cut", set_low_cut),
+            self.props.wireProperty("offset_freq", self.chain.setFrequencyOffset),
-            self.props.wireProperty("high_cut", set_high_cut),
+            # TODO check, this was used for wsjt-x
-            self.props.wireProperty("mod", self.dsp.set_demodulator),
+            # self.props.wireProperty("center_freq", self.dsp.set_center_freq),
-            self.props.wireProperty("dmr_filter", self.dsp.set_dmr_filter),
+            self.props.wireProperty("squelch_level", self.chain.setSquelchLevel),
-            self.props.wireProperty("wfm_deemphasis_tau", self.dsp.set_wfm_deemphasis_tau),
+            self.props.wireProperty("low_cut", self.chain.setLowCut),
-            self.props.wireProperty("digital_voice_codecserver", self.dsp.set_codecserver),
+            self.props.wireProperty("high_cut", self.chain.setHighCut),
+            self.props.wireProperty("mod", self.setDemodulator),
+            # TODO
+            # self.props.wireProperty("dmr_filter", self.dsp.set_dmr_filter),
+            # TODO
+            # self.props.wireProperty("wfm_deemphasis_tau", self.dsp.set_wfm_deemphasis_tau),
+            # TODO
+            # self.props.wireProperty("digital_voice_codecserver", self.dsp.set_codecserver),
             self.props.filter("center_freq", "offset_freq").wire(set_dial_freq),
         ]
 
-        self.dsp.set_temporary_directory(CoreConfig().get_temporary_directory())
+        # TODO
+        # sp.set_temporary_directory(CoreConfig().get_temporary_directory())
 
         def send_secondary_config(*args):
             self.handler.write_secondary_dsp_config(
@@ -152,9 +253,10 @@ class DspManager(Output, SdrSourceEventClient):
                 send_secondary_config()
 
         self.subscriptions += [
-            self.props.wireProperty("secondary_mod", set_secondary_mod),
+            # TODO
-            self.props.wireProperty("digimodes_fft_size", send_secondary_config),
+            # self.props.wireProperty("secondary_mod", set_secondary_mod),
-            self.props.wireProperty("secondary_offset_freq", self.dsp.set_secondary_offset_freq),
+            # self.props.wireProperty("digimodes_fft_size", send_secondary_config),
+            # self.props.wireProperty("secondary_offset_freq", self.dsp.set_secondary_offset_freq),
         ]
 
         self.startOnAvailable = False
@@ -163,10 +265,39 @@ class DspManager(Output, SdrSourceEventClient):
 
         super().__init__()
 
+    def _getDemodulator(self, demod: Union[str, BaseDemodulatorChain]):
+        if isinstance(demod, BaseDemodulatorChain):
+            return demod
+        # TODO: move this to Modes
+        demodChain = None
+        if demod == "nfm":
+            demodChain = NFm(self.props["output_rate"])
+        elif demod == "wfm":
+            demodChain = WFm(self.props["output_rate"], self.props["wfm_deemphasis_tau"])
+        elif demod == "am":
+            demodChain = Am()
+        elif demod in ["usb", "lsb", "cw"]:
+            demodChain = Ssb()
+        elif demod == "dmr":
+            demodChain = Dmr(self.props["digital_voice_codecserver"])
+        elif demod == "dstar":
+            demodChain = Dstar(self.props["digital_voice_codecserver"])
+        elif demod == "ysf":
+            demodChain = Ysf(self.props["digital_voice_codecserver"])
+        elif demod == "nxdn":
+            demodChain = Nxdn(self.props["digital_voice_codecserver"])
+
+        return demodChain
+
+    def setDemodulator(self, mod):
+        demodulator = self._getDemodulator(mod)
+        if demodulator is None:
+            raise ValueError("unsupported demodulator: {}".format(mod))
+        self.chain.setDemodulator(demodulator)
+
     def start(self):
         if self.sdrSource.isAvailable():
-            self.dsp.setBuffer(self.sdrSource.getBuffer())
+            self.chain.setReader(self.sdrSource.getBuffer().getReader())
-            self.dsp.start()
         else:
             self.startOnAvailable = True
 
@@ -187,7 +318,9 @@ class DspManager(Output, SdrSourceEventClient):
         threading.Thread(target=self.pump(read_fn, write), name="dsp_pump_{}".format(t)).start()
 
     def stop(self):
-        self.dsp.stop()
+        self.chain.stop()
+        self.chain = None
+
         self.startOnAvailable = False
         self.sdrSource.removeClient(self)
         for sub in self.subscriptions:
@@ -208,16 +341,15 @@ class DspManager(Output, SdrSourceEventClient):
         if state is SdrSourceState.RUNNING:
             logger.debug("received STATE_RUNNING, attempting DspSource restart")
             if self.startOnAvailable:
-                self.dsp.setBuffer(self.sdrSource.getBuffer())
+                self.chain.setReader(self.sdrSource.getBuffer().getReader())
-                self.dsp.start()
                 self.startOnAvailable = False
         elif state is SdrSourceState.STOPPING:
             logger.debug("received STATE_STOPPING, shutting down DspSource")
-            self.dsp.stop()
+            self.stop()
 
     def onFail(self):
         logger.debug("received onFail(), shutting down DspSource")
-        self.dsp.stop()
+        self.stop()
 
     def onShutdown(self):
-        self.dsp.stop()
+        self.stop()