Foreword, May 1980

The next generation of microwave digital systems will require much higher clock frequencies to increase computational speed. Both military and commercial electronics have applications for digital communications with multigigabit-per-second data rates, multi-phase-shift-keyed modulation/demodulation, time multiplexing, frequency division, counting, A/D converters, memories, and frequency and waveform synthesis. During the last several years, significant progress has been made in raising the operating speed of digital microcircuits above the 1-GHz/s level. Advances in silicon IC technology will generate some limited speed improvements, but GaAs IC technology offers a two- to six-times speed improvement for the immediate future and Josephson junction technology projects another two- to three-times speed improvement for the intermediate future.