diff --git a/src/main/java/com/xydl/cac/model/spectrogram/SouthYsp.java b/src/main/java/com/xydl/cac/model/spectrogram/SouthYsp.java
index 0b6e0ae..284bfee 100644
--- a/src/main/java/com/xydl/cac/model/spectrogram/SouthYsp.java
+++ b/src/main/java/com/xydl/cac/model/spectrogram/SouthYsp.java
@@ -16,8 +16,8 @@ public class SouthYsp extends SpectrogramModel {
     String name;
     Float xInterval;
     Float yMax;
-    Integer xUnit;
-    Integer yUnit;
+    String xUnit;
+    String yUnit;
     Integer k;
     Integer m;
     List<SouthYspChannel> channels = new ArrayList<>();
@@ -31,8 +31,8 @@ public class SouthYsp extends SpectrogramModel {
         name = readString(dis, 32);
         xInterval = readLittleEndianFloat(dis);
         yMax = readLittleEndianFloat(dis);
-        xUnit = dis.read();
-        yUnit = dis.read();
+        xUnit = readString(dis, 1);
+        yUnit = readString(dis, 1);
         k = readLittleEndianInt(dis);
         m = dis.read();
         for (int i = 0; i < m; i++) {