WiNRADiO G33DDC User’s Manual
107
Appendix A
– SDR and DDC Primer
This note is intended to help “traditional” radio enthusiasts understand the
technology differences between old style analog receivers and the new
generation of
Software Defined Radio
(
SDR
), especially with reference to the
WiNRADiO
Excalibur Pro
.
Analog Receivers
Prior to the era of computer-interfaced radio receivers, a block diagram of a
typical HF receiver would look similar to that below. Incoming radio signals are
down-converted via one or more conversion processes, all using analog
components, tuned circuits, and various amplifiers, mixers and oscillators.
Following the final down-conversion, the resulting signal is applied to a
demodulator, and then to the audio output circuits:
These receivers depend only on hardware for their performance and
functionality. In the currently prevailing nomenclature of the SDR industry, they
are formally referred to as
SDR Tier Zero
receivers, meaning that there is no
involvement of software at all.
First Generation SDR
With the proliferation of personal computers into every aspect of our life, some
manufacturers realized that the world of radio had essentially remained
unaffected by computers and the radio receivers of the day would benefit from
some degree of computerization. WiNRADiO led that movement with the
