Browse Prior Art Database

Digital Vertical Sync Regeneration for Video Display Systems

IP.com Disclosure Number: IPCOM000040488D
Original Publication Date: 1987-Nov-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Chaney, RS: AUTHOR [+3]

Abstract

A technique is described whereby the vertical synchronization signal, as used in video display systems, is recovered from a National Television System Committee (NTSC) video composite synchronization signal, so as to provide operational stability and full logic integration capability. The concept differs from prior art analog recovery techniques in that only digital circuitry is utilized, so as to improve the accuracy of vertical synchronization recovery. The concept also provides full logic integration capability to other digital logic gate array circuitry. (Image Omitted) In prior art, the utilization of NTSC video signals required the extraction of vertical and horizontal synchronization signals so as to identify all of the transmitted information.

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Digital Vertical Sync Regeneration for Video Display Systems

A technique is described whereby the vertical synchronization signal, as used in video display systems, is recovered from a National Television System Committee (NTSC) video composite synchronization signal, so as to provide operational stability and full logic integration capability. The concept differs from prior art analog recovery techniques in that only digital circuitry is utilized, so as to improve the accuracy of vertical synchronization recovery. The concept also provides full logic integration capability to other digital logic gate array circuitry.

(Image Omitted)

In prior art, the utilization of NTSC video signals required the extraction of vertical and horizontal synchronization signals so as to identify all of the transmitted information. The extraction process and the regeneration of the synchronization signals was typically performed using analog circuitry along with monostable multivibrators in conjunction with passive components. Due to the degradation of thermal and electrical characteristics of the components and devices, instability occurred over time. Also, the passive components used in prior art techniques precluded the possibility of total logic integration. The technique described herein eliminates the instability through the use of digital circuitry and provides logic integration. The digital vertical synchronization regenerator, as shown in Fig. 1, provides the required stabil...