I’ve been learning about software defined radio from the ground up and
my maths are a bit shaky and I’m mainly a software guy, so concepts of
signals and whatnot are rather foreign to me. So as I’ve been reading,
I’ve taken lots of tangents to review what must seem like completely
elementary concepts along the way.
I fully understood what ADCs and DACs do, but I didn’t have any clue
what complex sampling really was. I ended up stumbling across a document
from 1958 that seems to be when the concept of complex sampling was
developed. Please do correct me if I’m wrong, but either way- this
document seems to do a great job of explaining some of the maths of
complex signals and with a small trigonometry review, it should be more
clear just what a complex signal really is doing.
I imagine most of the folks on this list are well past needing this type
of review, but I’d highly recommend reading this if you need some of the
basics. It pertains in large part to Frequency Modulation. Without
further ado, here’s the URL: http://handle.dtic.mil/100.2/AD636038
I’ve also found the JNL Research Group’s gnuradio tutorial invaluable
(and is linked to in several places on the gnuradio pages IIRC)
(http://www.nd.edu/~jnl/sdr/docs/)
I found a fairly good article on Cascaded Integrator-comb filters as
well (http://www.us.design-reuse.com/articles/article10028.html)
http://www.dspguru.com has quite a bit of useful background too for
folks like me that need a lot of terminology defined.
All this may be referenced/linked elsewhere, but I figured I’d share
what has been useful to me so far.