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US 4,792,845 AGranted
Color video signal phase detector
AssigneeMagni Systems, Inc.
InventorJohn L. Judge
Life of this patent
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AssigneeMagni Systems, Inc.
InventorJohn L. Judge
Estimating the term…
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.
In a system for processing a color video signal representing plural video image scan lines and including for each of them a color synchronization burst signal and a horizontal synchronization pulse, a method of measuring the phase characteristics of the color video signal, comprising:
An electrical circuit for measuring the phase characteristics of a color video signal representing plural video image scan lines and including for each of them a color synchronization burst signal and a horizontal synchronization pulse, comprising:
In a system that employs a color video reference signal arranged in a first sequence of color frames and having a color synchronization burst signal and a horizontal synchronization pulse in processing a color video source signal arranged in a second sequence of color frames and having a color synchronization burst signal and a horizontal synchronization pulse, a method of detecting differences between the first and second sequences of color frames, comprising:
In a system which measures the phase angle between the horizontal synchronization pulse and the color synchronization burst signal of a color video signal, a method of displaying the value of the phase angle on a video monitor display screen, comprising:
A symbol for indicating on a display device the phase angle between the horizontal synchronization pulse and the color synchronization burst signal of a color video signal, comprising:
In a system that provides a signal proportional to the phase angle between the color synchronization burst signal and the horizontal synchronization pulse of a color video signal, an apparatus for displaying the phase characteristics on a display device, comprising:
Dependencies are inferred from the claim text.