Listening to FM Radio in Software, Step by Step
We've walked through a fully functional but stripped-down multichannel FM receiver. We managed to turn a couple thousand dollars' worth of hardware into the equivalent of two $5 transistor radios, and we learned a bunch in the process. For those of you interested in pursuing FM listening, the GNU Radio code base includes a substantially higher fidelity FM receiver (hifi_fm.py), along with all kinds of other goodies.
Right now, a lot of interesting work is being done with GNU Radio. Some are focusing on mobile ad hoc networking, others on the legacy amateur radio waveforms, some on software GPS and another group is working on designing the next-generation ground-to-space amateur satellite communication system. Although the GNU Radio toolkit is mostly indifferent to I/O devices, most of these efforts are using or planning on using the USRP as the interface between the RF world and the PC.
Resources for this article: /article/7650.
Eric Blossom is the founder of the GNU Radio Project. Prior to his involvement with software radio, he spent many years in the secure phone business. When he's not hacking software radio, you're likely to find him practicing yoga or jujutsu. He can be reached at firstname.lastname@example.org.
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