Software Defined Radio or SDR refers to a radio communication system that has conventional hardware like filters, mixers, modulators, detectors, demodulators and more, implemented as software.
To use SDR a (personal) computer with an audio interface or a digital to analog converter linked to a RF front end is needed. this combination creates a radio that can receive and transmit just about any radio protocols (waveforms) based completely on software. More information on Software Defined Radio can be found here at Wikipedia.
In this project we will limit SDR to reception only, leaving the radio tuning and analog to digital conversion to the low cost DBV-T USB dongle.