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:
Dec. 20, 1988
Filed:
Feb. 20, 1987
John L Judge, Hillsboro, OR (US);
Magni Systems, Inc., Beaverton, OR (US);
Abstract
A method and an electrical circuit determines the phase relationship between the color synchronization burst signal and horizontal synchronization pulses of a single color video signal and the color frame relationship between two color video signals. This is accomplished by regenerating on a line-by-line basis a color subcarrier signal which has a fixed phase relative to the leading edge of a horizontal synchronization pulse. A phase comparison is then made between regenerated color subcarrier signal and the color synchronization burst signal to develop a signal that represents the amount of phase error. The phase error signal is sampled to determined an average phase error for successive lines of the color video signal. Simultaneously, a phase comparison is also made between a 90.degree. phase-displaced version of the color synchronization burst signal and the regenerated color subcarrier signal to provide a quadrature phase error signal. The quadrature phase error signal can be compared to a color video reference signal to determine whether they have the same color frame. Both the video signal and the reference signal have independent timing circuits so that the signals need not be in synchronism to determine a color frame error. The amount of phase error and the existence of color frame mismatch is communicated to a user by means of a visual display monitor. The error is displayed as a separate image from other video images such that the size of the error image increases with an increase in phase error.