diff --git a/csdr/chain/am.py b/csdr/chain/am.py
index 64416e5..e57fa9a 100644
--- a/csdr/chain/am.py
+++ b/csdr/chain/am.py
@@ -1,10 +1,9 @@
 from csdr.chain import Chain
-from csdr.chain.demodulator import Demodulator
 from pycsdr.modules import AmDemod, DcBlock, Agc, Convert
 from pycsdr.types import Format, AgcProfile
 
 
-class Am(Demodulator):
+class Am(Chain):
     def __init__(self):
         agc = Agc(Format.FLOAT)
         agc.setProfile(AgcProfile.SLOW)
@@ -12,13 +11,8 @@ class Am(Demodulator):
         workers = [
             AmDemod(),
             DcBlock(),
-            # empty chain as placeholder for the "last decimation"
-            Chain(),
             agc,
             Convert(Format.FLOAT, Format.SHORT),
         ]
 
         super().__init__(*workers)
-
-    def setLastDecimation(self, decimation: Chain):
-        self.replace(2, decimation)
diff --git a/csdr/chain/demodulator.py b/csdr/chain/demodulator.py
index 0f91336..2960a6f 100644
--- a/csdr/chain/demodulator.py
+++ b/csdr/chain/demodulator.py
@@ -1,16 +1,10 @@
 from csdr.chain import Chain
-from pycsdr.modules import Module, Shift, FirDecimate, Bandpass, Squelch, FractionalDecimator
-from abc import ABCMeta, abstractmethod
-
-
-class Demodulator(Chain, metaclass=ABCMeta):
-    @abstractmethod
-    def setLastDecimation(self, decimation: Module):
-        pass
+from pycsdr.modules import Shift, FirDecimate, Bandpass, Squelch, FractionalDecimator
+from pycsdr.types import Format
 
 
 class DemodulatorChain(Chain):
-    def __init__(self, samp_rate: int, audioRate: int, shiftRate: float, demodulator: Demodulator):
+    def __init__(self, samp_rate: int, audioRate: int, shiftRate: float, demodulator: Chain):
         self.shift = Shift(shiftRate)
 
         decimation, fraction = self._getDecimation(samp_rate, audioRate)
@@ -23,16 +17,12 @@ class DemodulatorChain(Chain):
 
         self.squelch = Squelch(5)
 
-        if fraction != 1.0:
-            demodulator.setLastDecimation(FractionalDecimator(fraction))
+        workers = [self.shift, self.decimation]
 
-        workers = [
-            self.shift,
-            self.decimation,
-            self.bandpass,
-            self.squelch,
-            demodulator
-        ]
+        if fraction != 1.0:
+            workers += [FractionalDecimator(Format.COMPLEX_FLOAT, fraction)]
+
+        workers += [self.bandpass, self.squelch, demodulator]
 
         super().__init__(*workers)
 
diff --git a/csdr/chain/fm.py b/csdr/chain/fm.py
index f5ef6bd..150cce4 100644
--- a/csdr/chain/fm.py
+++ b/csdr/chain/fm.py
@@ -1,9 +1,9 @@
-from csdr.chain.demodulator import Demodulator, Chain
+from csdr.chain import Chain
 from pycsdr.modules import FmDemod, Limit, NfmDeemphasis, Agc, Convert
 from pycsdr.types import Format, AgcProfile
 
 
-class Fm(Demodulator):
+class Fm(Chain):
     def __init__(self, sampleRate: int):
         agc = Agc(Format.FLOAT)
         agc.setProfile(AgcProfile.SLOW)
@@ -11,13 +11,8 @@ class Fm(Demodulator):
         workers = [
             FmDemod(),
             Limit(),
-            # empty chain as placeholder for the "last decimation"
-            Chain(),
             NfmDeemphasis(sampleRate),
             agc,
             Convert(Format.FLOAT, Format.SHORT),
         ]
         super().__init__(*workers)
-
-    def setLastDecimation(self, decimation: Chain):
-        self.replace(2, decimation)
diff --git a/csdr/chain/ssb.py b/csdr/chain/ssb.py
index e10ae96..cf94d42 100644
--- a/csdr/chain/ssb.py
+++ b/csdr/chain/ssb.py
@@ -1,10 +1,9 @@
 from csdr.chain import Chain
-from csdr.chain.demodulator import Demodulator
 from pycsdr.modules import RealPart, Agc, Convert
 from pycsdr.types import Format
 
 
-class Ssb(Demodulator):
+class Ssb(Chain):
     def __init__(self):
         workers = [
             RealPart(),