The availability of inexpensive SDR hardware such as the RTL-SDR and Funcube Dongle help to focus interest on the GNU Radio open source signal processing software. In this video from CCC Camp 2011 Marius Ciepluch delivers a case-study on how to analyze 802.15.4 (alias Zigbee) with USRPs on a real-time protocol (for send time verification, sniffing etc.). Marius attempts to explain the internals of DSP in simple terms for non-experts using demos analyzing ISM band signals.