
US Patent No: 4,553,161
Number of patents in Portfolio can not be more than 2000
Upstream data packet time slot synchronization with downstream VBI for two-way CATV system
Stats
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Nov 12, 1985
Issued date -
Sep 6, 1984
filing date -
06/648,569
serial no -
Expired
status
Importance
Abstract
Synchronization of upstream data packet time slots with the vertical blanking interval (VBI) of a video signal transmitted downstream from the headend is provided in a two-way cable television (CATV) system. Coded data transmitted during a designated VBI line from the CATV headend is compared with system data stored in each subscriber terminal for generating a match signal. The match signal is used to interrupt a microcomputer which then divides the next video signal raster scan field into 8 equal time slots during any one of which an upsteam data packet may be transmitted. Upstream data is thus accurately synchronized with a downstream vertical scan rate signal in reducing the likelihood of collisions between upstream data packets and increasing through-put in a two-way CATV system.
First Claim
Related Publications
International Classification(s)
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Cited Art
| Patent Info | (Count) | # Cites | Year |
|---|---|---|---|
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| 4,398,289 Method for the transmission of data packets | 54 | 1981 | |
| 4,398,298 Communication system having stations capable of detecting another station's | 8 | 1981 | |
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| 4,250,524 Validation apparatus in a pay television system | 75 | 1979 | |
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| 4,430,731 Video and data distribution module with subscriber terminal | 136 | 1981 | |
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| 4,454,538 Data communication in CATV system | 92 | 1982 | |