| 摘要 |
<p>-1- RCA 74, 014 IMPROVED ERROR CODING FOR VIDEO DISC SYSTEM The present invention relates generally to video disc systems, and more particularly to error codes used in video disc systems for encoding and decoding digital information on a recorded video signal. In video disc systems, certain advanced features maybe implemented by recording digital information along with the video signal. Examples of such advanced features include automatically skipping over locked groove defects, display of program playing time, and automatic end-of-program detection. Copending patent application "IMPROVED DIGITAL ON VIDEO RECORDING AND PLAYBACK SYSTEM" by T. Christopher and C. Dieterich, and assigned to the same assignee of the present invention, discloses a video disc system including a player having a simple, efficient, video-to-digital interface for separating prerecorded digital information from the video signal and how such digital information is used to implement the above-mentioned features. Additionally, it is important that the digital data read by the player be substantially free of undetected errors. Copending application "VIDEO DISC SYSTEM" by C. Dieterich and assigned to the same assignee as the present invention, discloses a digital data recording and playback system suitable for use with the present invention. The recorded digital format disclosed in the latter above-mentioned patent application comprises a start code, an error code, and information bits. During playback, the video disc player samples digital data encoded on the video signal until a start code is detected. After the start code is detected, the error code and the information bits are clocked into appropriate registers. In a sequential process, the error code and information bits are decoded to determine if there is an error. The decoding process results in a predetermined constant (referred to herein as a remainder) if no errors are detected. Various hardware configurations are available for decoding a digital message in accordance with the above-mentioned format. Minimum requirements include data storage means for storing received data, error code check means including an error code check register for computing a remainder, means for detecting a start code, means for detecting a valid remainder, and control RCA 74,014 IMPROVED ERROR CODING FOR VIDEO DISC SYSTEM An improved error code used for encoding and decoding data in a video disc system of the type wherein the data format comprises a start code followed by an error code and information bits. The error code is chosen so that the error code check register in the video disc player begins with the start code in the register, and, if no errors are detected after the full message is received, also ends with the start code in the register. This unique code simplifies both the control logic and the decoding logic in the video disc player decoder.</p> |
