U.S. Philips Corporation

Ulrich Mohlmann

Jorg Wolber

Gerd Onken

Dieter J Kunze

A digital phase-locked loop (PLL) which responds to a square-wave input signal of on expected frequency f.sub.E and comprises a change-over switch which is switched in response to square-wave signals or different frequencies and precedes a main divider operating with a divisor D and which produces the output signal of the phase-locked loop. The change-over switch is activated as a function of the output signal and the input signal. In order to provide symmetrical locking in of the phase-locked loop and a small capture-and-hold range, the change-over switch is switched between a first square-wave signal of the frequency f.sub.1, a second square-wave signal of the second frequency f.sub.2 and a third square-wave signal of the frequency f.sub.3, in which:

Growing community of inventors

Munich, Georgia

Ulrich Mohlmann