diff --git a/lisainstrument/instrument.py b/lisainstrument/instrument.py
index a7ab46f601e7a4f31178df912e93df19a2b8c459..04489fa03382e15f260af48e47d1453c0cf7b043 100755
--- a/lisainstrument/instrument.py
+++ b/lisainstrument/instrument.py
@@ -808,12 +808,9 @@ class Instrument:
         ## Timer deviations from TCB
 
         self.tcb_timer_deviations = \
-            self.clock_offsets + \
-            self.clock_freqoffsets * self.telemetry_t + \
-            self.clock_freqlindrifts * self.telemetry_t**2 / 2 + \
-            self.clock_freqquaddrifts * self.telemetry_t**3 / 3 + \
-            self.tps_proper_time_deviations + \
-            self.tcb_sync_noises
+            self.local_timer_deviations \
+            + self.tps_proper_time_deviations \
+            + self.tcb_sync_noises
 
         ## TDIR tone
 
@@ -1407,7 +1404,7 @@ class Instrument:
         ## TCB synchronization noise
 
         self.tcb_sync_noises = ForEachSC(lambda sc:
-            noises.white(self.telemetry_fs, self.telemetry_size, self.sync_asds[sc])
+            noises.tcb_sync(self.telemetry_fs, self.telemetry_size, self.sync_asds[sc])
         )
 
         ## Angular jitters
diff --git a/lisainstrument/noises.py b/lisainstrument/noises.py
index 0e2f0f36b910b6862ab29dea2b1406ca428bb721..3192294ed57afeeb071b27dda4b97bc8e79ee09b 100644
--- a/lisainstrument/noises.py
+++ b/lisainstrument/noises.py
@@ -301,3 +301,20 @@ def dws(fs, size, asd=7E-8/335):
     """
     logger.debug("Generating DWS measurement (fs=%s Hz, size=%s, asd=%s rad/sqrt(Hz))", fs, size, asd)
     return violet(fs, size, 2 * pi * asd)
+
+def tcb_sync(fs, size, asd):
+    """TCB synchronization noise.
+
+    High-level noise model for the uncertainty we have in estimating
+    the TCB timer deviations, i.e., the equivalent TCB times for the
+    equally-sampled TPS timestamps.
+
+    Assumed to be a white noise in timing,
+
+        S_tcbsnc(f) [s] = asd^2.
+
+    Args:
+        asd: amplitude spectral density [s/sqrt(Hz)]
+    """
+    logger.debug("Generating TCB synchronization noise (fs=%s Hz, size=%s, asd=%s s/sqrt(Hz))", fs, size, asd)
+    return white(fs, size, asd)