Radio systems come in a large variety of complexities tailored to the myriads of communications applications in daily use. HCDC specializes in the design, analysis, and prototype implementation of experimental digital radios including error protection methods and protocol stacks. The picture shows an OFDM system implemented on Xilinx VC 707 experimental boards and interfaced with Analog Devices Radio cards. The scope shows a spectral measurement of HCDC’s proprietary distributed pilot signal waveform. Synchronization, frequency-domain equalization, and Doppler compensation algorithms are implemented as FPGA cores using Xilinx’s most recent Vivado design suite.