Symmetricom will resell GPS Disciplined Oscillator (GPSDO) Modules and High-Frequency Source Modules from Jackson Labs Technologies, Inc., a designer and manufacturer of cutting-edge precision time and frequency products.
GPSDOs provide time and frequency reference signals that have the same long-term accuracy as the GPS signal itself, and also provide a “holdover” capability to maintain system synchronization when GPS reception outages occur. http://www.symmetricom.com