Found another interesting thesis that explains it very well http://rrsg.uct.ac.za/theses/ug_projects/george_ugthesis.pdf 73s Steve G1YLB -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/attachments/20100706/cb19dbdf/attachment-0003.htm>