Superconducting Bandpass ADC Technology for Digitization at RF

HYPRES proposes to develop a superconducting digital-RF receiver with very high signal-to-noise ratio (SNR) and spur-free dynamic range (SFDR) to meet the requirements of future software radios for both military and commercial wireless communications. Thisrequires direct digitization of the RF signal, followed by down-conversion in the digital domain, replacing the nonlinear analog mixer in a conventional receiver. Superconducting ADCs, sampled up to 20 GHz rates, have already demonstrated superiorperformance in low-pass architectures. New circuit designs are needed to translate them to the bandpass architecture and to enhance performance. Our objective is to achieve at least 100 dB (16 effective bits) of SNR and SFDR over a 10-100 MHz bandwidth atfrequencies up to 2 GHz, which is not achievable by conventional electronics. During Phase I, several alternative circuit architectures will be investigated and a plan for progressive development will be established. In Phase II, starting with a Phase IOption, ADC circuits will be fabricated and integrated with programmable digital mixer and decimation filters. This complete receiver will be tested and compared to simulated performance. An improved bandpass analog-to-digital converter is an essentialenabling component for next generation software radio. Elimination of frequency and protocol-specific analog components by broadband digitization, followed by digital processing, enables agile, inter-operable, reconfigurable communication transceivers asrequired by the Joint Tactical Radio System (JTRS). While the performance demands of commercial wireless communications systems lag well behind those of the military, software radio will pervade the commercial world in the next few years. Finally, inaddition to communication systems, superconductive digital-RF technology will improve other military RF systems, such as radar and electronic warfare.