diff --git a/egs/librispeech/ASR/conv_emformer_transducer_stateless3/emformer.py b/egs/librispeech/ASR/conv_emformer_transducer_stateless3/emformer.py
index c8e202bac..21ef4b18e 100644
--- a/egs/librispeech/ASR/conv_emformer_transducer_stateless3/emformer.py
+++ b/egs/librispeech/ASR/conv_emformer_transducer_stateless3/emformer.py
@@ -2109,6 +2109,8 @@ class RelPositionalEncoding(torch.nn.Module):
             self.pe_negative = self.pe_negative.to(dtype=dtype, device=device)
         pe = torch.cat(
             [
+                # it starts from the min negative value of relative position
+                # and it is bound to be gathered
                 self.pe_negative[self.neg_len - neg_len :],
                 self.pe_positive[1:pos_len],
             ],