This research project focuses on monolithic high-frequency (1-1000 MHz) communications circuits and is directed at exploring new ways to use silicon integrated-circuit technology to improve the performance and reduce the cost of communications systems of various kinds with primary emphasis on data communications. Particular emphasis is placed on circuit techniques applicable to the photocurrent amplifier and the clock recovery problem in fiber-optic receivers. The following four specific areas are being investigated: fundamental performance limits in fiber-optic transceivers, low- noise switched-capacitor filters, wideband MOS amplifiers with low input-noise voltage, and device modeling for MOS analog circuit design.