Low Noise Buffer Amplifiers and Buffered Phase Comparators for Precise Time and Frequency Measurement and Distribution

摘要

Extremely low noise, high performance, wideband buffer amplifiers and buffered phase comparators have been developed for the NASA Goddard Space Flight Center Atomic Hydrogen Standards Program. These buffer amplifiers are designed to distribute reference frequencies from 30 KHz to 45 MHz from a hydrogen maser without degrading the hydrogen maser's performance. The buffered phase comparators are designed to intercompare the phase of state- of-the-art hydrogen masers without adding any significant measurement system noise. These devices have a 27 femtosecond phase stability floor and are stable to better than one picosecond for long periods of time. Their temperature coefficient is less than one picosecond per degree C, and they have shown virtually no voltage coefficients . When used in distribution amplifiers and phase comparison systems, these devices have greater than 90 dB of isolation.