Ultrawideband (5 GHz) mixed-signal front end and recorder for software defined radio

Dual 5 Gsps ADCs and DACs are used to provide a waveform-agnostic mixed-signal front end. The digitized data is sent over a 100 GbE network to one or more off-the-shelf servers. A small FPGA is used to interface between the ADC/DAC and Ethernet. The FPGA firmware allows the user to specify packet destination(s) for either unicast or multicast UDP. Processing the enormous volume of data (10 GB/s) generated by the front end in real time is challenging. This paper addresses lessons learned in selecting appropriate hardware, tuning of the Linux kernel, and software optimization. While the system is designed for a fully-featured software defined radio, the initial implementation only records the received data to disk and plays it back. The paper also addresses the cost and risk tradeoffs considered during the system development.