Software defined radio has become a staple of the RF tinkerer, but it’s likely that very few of us have ever taken their software defined toolchain outside the bounds of radio. It’s an area explored by Mike Ossmann and Kate Temkin in their newly published Supercon talk as they use GNU Radio to do some things that you might find unexpected.
For most people, a software defined radio is a device. An RTL-SDR dongle perhaps, or the HackRF that a popular multi-tool for working in the radio frequency realm. But as they explain, the SDR hardware can be considered merely as the analogue front end, being just the minimal analogue circuitry coupled with a digitiser. The real software-defined part comes — as you might expect — in the software
Kate and Mike introduce GNU Radio Companion — the graphical UI for GNU Radio — as their tool of choice and praise it’s use as a general purpose digital signal processing system whether or not that includes radio. Taking their own Great Scott Gadgets GreatFET One USB hackers toolkit peripheral as an input device they demonstrate this by analysing the output from a light sensor. Instantly they can analyse the mains frequency in a frequency-domain plot, and the pulse frequency of the LEDs. But their bag of tricks goes much deeper, exploring multiple “atypical use cases” that unlock a whole new world through creative digital signal processing (DSP).