Radio Frequency Front End

Hydra's RF front-end is the Universal Software Radio Peripheral developed by Ettus Research for use with GNU Radio. The USRP is comprised of a baseband board and up to two RF daughter cards. The baseband board is composed of a USB 2.0 controller, a million gate FPGA, and multiple high-speed DA and AD converters. The FPGA provides control functionality, FIFO data queueing, as well as decimation/interpolation filtering. The baseband board's four high-speed DA and AD converters operate at 128 and 64 mega-samples-per-second respectively. The DA/AD converters also have programmable gain amplifiers controlled by the FPGA. All of the control and data manipulation functionality of the baseband board can be controlled in software running on the GPP; and all data and control signals are communicated to the front-end over USB.

Universal Software Radio Peripheral from Ettus Research, LLC.

GNU Radio defines a flexible API for the front-end that also supports reconfiguration of the RF daughter cards. The daughter cards are frequency agile radio transceivers with programmable gain control. They can be swapped to allow transceiver operation in various frequency bands (e.g. 400-500 MHz, ISM band, etc.). Additionally, the front-end features a fully synchronous design that allows multiple daughter cards to be synchronized providing support for research in multiple antenna systems.