diff --git a/apps/plugins/pitch_detector.c b/apps/plugins/pitch_detector.c
index 461b8562d8..7e8cfeaa0e 100644
--- a/apps/plugins/pitch_detector.c
+++ b/apps/plugins/pitch_detector.c
@@ -262,7 +262,7 @@ static int recording=0;
 struct note_entry
 {
     const char *name;    /* Name of the note, e.g. "A#" */
-    const fixed freq;    /* Note frequency              */
+    const fixed freq;    /* Note frequency, Hz          */
     const fixed logfreq; /* log2(frequency)             */
 };