Part_1 Part_2 Part_3 Part_4	Software Defined Radio for the Masses Gerald Youngblood, AC5OG Founder of Flex Radio
WebSdr	Getting started guide to using Web SDR
DSP Related	A brilliant website with many great articles
Lyons-1	Rick Lyons’ “Complex but not Complicated” explanation of IQ signals
Lyons-2	An invaluable reference by Rick Lyons, reducing the multiplies in an IIR filter
Robertson-1	Neil Robertson explains why window functions are important to using the DFT
Robertson-2	Neil explains why relating a DFT output to the familiar spectrum analyser output is tricky.
Online	One of many, but also available as a downloadable book
SDR4Engineers	From the great folks at Analog Devices, the only downside is that all the code is in Matlab
PySDR	A very comprehensive guide to SDR using python to demonstrate many priinciples