The NATO III 5 MHz distribution system

A high performance 5 MHz distribution system is presented, which has extremely low phase noise and jitter characteristics to provide multiple buffered outputs. The system provides basic reference frequencies for both a transportable and fixed satellite ground station, and faults can be isolated to a modular level by observing from panel status indicators. Unique circuit design and packaging concepts are used to insure that isolation between outputs is sufficient to guarantee a phase perturbation of less than 0.0016 deg when other outputs are open circuits, short circuited or terminated in 50 ohms. Circuit design techniques include high isolation cascade amplifiers, and the use of negative feedback to stabilize system gain and minimize circuit phase noise contributions.