http://www.diku.dk/hjemmesider/ansatte/jda/biosignal/
http://cnx.org/content/m13046/latest/
http://www.iteye.com/topic/739585
http://www.dsprelated.com/showmessage/31035/1.php
https://developer.apple.com/library/ios/#documentation/Accelerate/Reference/vDSPRef/Reference/reference.html#//apple_ref/doc/uid/TP40009464
http://www.iteye.com/wiki/blog/1454971
http://fecbob.pixnet.net/blog/post/34683141-%5Biphone%5Davtouch程式碼