diff --git a/egs/librispeech/ASR/conv_emformer_transducer_stateless/emformer.py b/egs/librispeech/ASR/conv_emformer_transducer_stateless/emformer.py
index 509eed3c8..c425fe67c 100644
--- a/egs/librispeech/ASR/conv_emformer_transducer_stateless/emformer.py
+++ b/egs/librispeech/ASR/conv_emformer_transducer_stateless/emformer.py
@@ -1585,7 +1585,7 @@ class EmformerEncoder(nn.Module):
         memory_mask = (
             (
                 (
-                    num_processed_frames << int(math.log(self.chunk_length, 2))
+                    num_processed_frames >> int(math.log(self.chunk_length, 2))
                 ).view(x.size(1), 1)
                 <= torch.arange(self.memory_size, device=x.device).expand(
                     x.size(1), self.memory_size
diff --git a/egs/librispeech/ASR/conv_emformer_transducer_stateless2/emformer.py b/egs/librispeech/ASR/conv_emformer_transducer_stateless2/emformer.py
index 1d16682c6..c1175d395 100644
--- a/egs/librispeech/ASR/conv_emformer_transducer_stateless2/emformer.py
+++ b/egs/librispeech/ASR/conv_emformer_transducer_stateless2/emformer.py
@@ -1493,7 +1493,7 @@ class EmformerEncoder(nn.Module):
         memory_mask = (
             (
                 (
-                    num_processed_frames << int(math.log(self.chunk_length, 2))
+                    num_processed_frames >> int(math.log(self.chunk_length, 2))
                 ).view(x.size(1), 1)
                 <= torch.arange(self.memory_size, device=x.device).expand(
                     x.size(1), self.memory_size