diff --git a/pyrelacs/dataio/circbuffer.py b/pyrelacs/dataio/circbuffer.py
index 8f7b92d..ce4f887 100644
--- a/pyrelacs/dataio/circbuffer.py
+++ b/pyrelacs/dataio/circbuffer.py
@@ -4,7 +4,7 @@ from IPython import embed
 
 
 class CircBuffer:
-    def __init__(self, size: int, channels: int = 1, samplerate: float = 40_000):
+    def __init__(self, size: int, channels: int = 1, samplerate: int = 40_000):
         self.__size = size
         self.__channels = channels
         self.__samplereate = samplerate
@@ -14,6 +14,7 @@ class CircBuffer:
         self.__index = [0 for i in range(channels)]
         self.__is_full = [False for i in range(channels)]
         self.__totalcount = [0 for i in range(channels)]
+        self.__time = [0.0 for i in range(channels)]
         self.__overflows = [0 for i in range(channels)]
 
     @property
@@ -41,6 +42,7 @@ class CircBuffer:
         self.__buffer[channel, self.write_index(channel)] = item
         self.__index[channel] = (self.write_index(channel) + 1) % self.__size
         self.__totalcount[channel] += 1
+        self.__time[channel] += 1 / self.__samplereate
         if self.__index[channel] == 0:
             self.__is_full[channel] = True
             self.__overflows[channel] += 1