diff --git a/Transceiver52M/device/common/smpl_buf.h b/Transceiver52M/device/common/smpl_buf.h
index 24d3ce9..383c814 100644
--- a/Transceiver52M/device/common/smpl_buf.h
+++ b/Transceiver52M/device/common/smpl_buf.h
@@ -7,6 +7,8 @@
  *
  * Author: Tom Tsou <tom.tsou@ettus.com>
  *
+ * SPDX-License-Identifier: AGPL-3.0+
+ *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or