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US 4,959,718 AGranted
Video device synchronization system
AssigneeAmpex Corporation
InventorPhillip P. Bennett
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AssigneeAmpex Corporation
InventorPhillip P. Bennett
Estimating the term…
A TV video signal synchronization signal system enables a video device such as a digital special effects system to operate synchronously in response to an input video signal and still produce an output video signal synchronized to a television studio locking reference signal. The video device and the synchronization signal generating subsystem thereof operate in response to a pixel rate clock of approximately 70 ns and in response to a phase command to generate timing for the horizontal sync pulse, color burst signal and video data of the output video signal. The output color burst signal remains phase locked to the locking reference signal with output gating being responsive to the phase command. A ROM interpolator provides subpixel accuracy for the output horizontal sync pulse while output line buffering and interpolation permits the output video data to the phase matched to the reference master sync signal. The entire video system thus operates synchronously with the input video signal to avoid noise interference problems which result from multiple phase clock signals while generating a composite output video signal that is properly phase synchronized with a studio locking reference signal.
Apparatus for digitally generating a television synchronizing signal having a selected phase relative to a reference signal, said apparatus comprising:
Apparatus for digitally generating an output signal having a leading edge with a predetermined rise time and a trailing edge with a predetermined fall time and having a selected phase relative to a reference signal, said apparatus comprising:
A video synchronization system comprising a phase detector coupled to receive a video synchronization signal and a locking reference signal and to generate a phase difference signal indicative of phase difference therebetween, a video sync generator coupled to receive a sync timing signal and a phase control signal that is responsive to the phase difference signal and to generate as an output a video synchronizing signal having a phase difference, relative to the sync timing signal, indicated by the phase control signal, wherein the video sync generator comprises a memory which stores a multiplicity of digital values which are addressable in sets to provide respective sequences of signal magnitudes representative of differently phased versions of the synchronizing signal, and an address generator operative in response to the phase control signal to select a set of the digital values so as to provide the required output video synchronizing signal.
A method of generating a video synchronizing signal for combination with a video information signal and having a selected phase relative to a reference, comprising storing in a memory a multiplicity of digital values which are addressable in sets to provide respective sequences of signal magnitudes representing differently phased versions of the synchronizing signal, providing a phase control signal which indicates the selected phase, and addressing the memory in response to the phase control signal to select a set of the digital values so as to provide the video synchronizing signal as constituted by the selected set of digital values.
Dependencies are inferred from the claim text.