The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 03, 1989
Filed:
Jan. 20, 1988
Dirk J Teuling, Eindhoven, NL;
Jozef J Hulshof, Eindhoven, NL;
U. S. Philips Corporation, New York, NY (US);
Abstract
A line sychronizing circuit in a picture display device, has a phase control loop including an oscillator and a phase comparison stage. In order to enlarge the capture range of the control loop, the phase comparison stage is in the form of a phase-frequency detector having a trigger action on edges of pulses applied, the circuit being provided with means for inhibiting the supply of the control signal form the phase-frequency detector during a predetermined period after establishing that the phase difference measured by the phase-frequency detector between the local line-frequency signal and the incoming line synchronizing signal is larger than a predetermined value. In the perdetermined period, the oscillator signal has substantially the same frequency as before establishing that the phase difference measured by the phase frequency detector is larger than the predetermined value. The supply of the control signal is restored during a second predetermined period after the supply of the control signal has been inhibited, and this irrespective of the phase difference between the local line signal and the incoming line synchronizing signal.