http://www.cqham.ru/forum/showthread.php?32807-%CF%F0%EE%F1%F2%FB%E5-SDR-%EF%F0%E8%E5%EC%ED%E8%EA%E8-%EF%E5%F0%E5%E4%E0%F2%F7%E8%EA%E8&p=1538678#post1538678
http://www.m0kgk.co.uk/sdr/