A Phase-Locked Primary Frequency Supply for the L Multiplex

Abstract

The carriers and pilot tones of the L multiplex are all derived from a single source of 4 Kc. The new primary frequency supply provides this primary frequency. It is designed to operate phase‐locked to a pilot tone derived from an incoming carrier system and hence to have no frequency error with respect to that tone. The unit features a high degree of frequency stability, even in the absence of the pilot; it features more reliable performance and lower maintenance as well as marked size reduction compared with the older equipment.