Billy K Swift

US Patent:

42874807, Sep 1, 1981

Filed:

Jan 10, 1980

Appl. No.:

6/111134

Inventors:

Billy K. Swift - Phoenix AZ
Anthony F. Zizzo - Phoenix AZ
Willard A. Blevins - Glendale AZ

Assignee:

Sperry Corporation - New York NY

International Classification:

H03L 710

US Classification:

331 1A

Abstract:

The out-of-lock condition of a digital phase locked loop is detected during a plurality of states such that single bit discrepancies, such as a noise pulse, are ignored, and thus the tolerable range of phase detection error is broadened. The present invention is adaptable for use with typical applications of digital phase locked loops, and can be used to control the phase detector of the digital phase locked loop such that error voltages will be introduced into the loop only during selected states.