Update README.md

README.md

@@ -1,6 +1,6 @@
 # WSPR CUI code
 
-* Based on wsprd and wsprcode source taken from WSJT-X 2.3.0-rc2
+* Based on wsprd and wsprcode source taken from WSJT-X 2.7.1
 * wsprsimwav derived from wsprsim
 * Code of CUI interface for WSPR TX/RX is at `wspr-trx/`
 
@@ -32,6 +32,7 @@ Note: tips for only WSPR-2 minute protocol are described unless otherwise noted
 ### For generating wav file
 
 * Use wsprsimwav for generating a 48kHz mono WAV file, directly usable for transmission over USB transmitter
+* The first and last 20 milliseconds parts of the sound generated by wsprsimwav are faded in/out with the raised-cosine envelope to reduce spurious emission
 
 ### For reading wav file by wsprd