The past three decades or so have seen a steady increase in the capabilities of digital computers. With those increased capabilites has come the development of techniqes that allow computers to perform tasks that had previously been accompished only through physical (analog) means. Whole fields of endeavor that existed as manual, mechanical, or chemical processes, have been transformed into virtual processes performed on various incarnations of digital computers. Publishing, photography, graphics, telephony – the list goes on.
The digitization of the analog world is finally coming to Amateur Radio. As the price of digital integrated circuits capable of operating at radio frequencies drops to affordable levels, analog electronic circuits are being replaced by software alogrithms, with analog-to-digital and digital-to-analog converters bridging between the physical and the virtual worlds.
Doing radio in software offers two primary advantages. First, it provides improved methods of performing the basic signal processing that makes radio work. Second, it opens up a range of capabilites that simply are not possible with analog methods. These are the things I will explore here.