Superconductive digital instantaneous frequency-measurement subsystem

A five-bit high-temperature-superconductive digital instantaneous frequency-measurement (DIFM) subsystem has been constructed for the determination of the frequency of unknown signals over a 500 MHz bandwidth, centered on 4 GHz, with a resolution of +/- 7.8 MHz. The subsystem contains a cryogenic section with five discriminator modules utilizing superconductive delay lines, GaAs mixers, and power dividers. With a single-tone cw input between -40 dBm and +10 dBm, the frequency quantization boundaries of the subsystem are, on average, 3.1 MHz from their design values. This system demonstrates the potential system-level application of high-temperature superconductive electronics in instrumentation, communication, radar, and electronic warfare.