Various GNURadio Blocks to interface with SDR Hardware

This is work in progress! Right now there are two blocks, which are specific to Ettus SDR Hardware.

This Block tries to change the internal time of a UHD SDR to the absolute time provided by the integerated gpsdo of it. Additional this block sends the NMEA data of the gpsdo to a local UDP socket, where it can be parsed by the gpsd Daemon. For debugging purposes this block has a message output where it is possible to monitor the GPS lock as well as the gps and internal time of the SDR.

gpsd -nNG udp://localhost:12345

This Block changes the center frequency of an UHD SDR by generating control messages as described in the GNURadio documentation.