转载:polyphase filter
http://www.ws.binghamton.edu/fowler/fowler%20personal%20page/ee521.htm
http://www.ws.binghamton.edu/fowler/fowler%20personal%20page/EE521_files/IV-05%20Polyphase%20FIlters_2007.pdf
http://www.ws.binghamton.edu/fowler/fowler%20personal%20page/ee521.htm
http://www.ws.binghamton.edu/fowler/fowler%20personal%20page/EE521_files/IV-05%20Polyphase%20FIlters_2007.pdf