Intermediate picture field storage system for variable speed magnetic tape video data read-out

US4905099A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Roland Mester · Darmstadt, DE
• Jurgen Heitmann · Zwingenberg, DE
• Rolf Loos · Eppertshausen, DE
• Jurgen Muller · Wulfen, DE

Key dates

• Filing date: Jun 1, 1988
• Grant date: Feb 27, 1990
• Expiry date: Jun 1, 2008

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N9/877
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

Four picture field memories which contain storage places for luminance data, chrominance data, error flags and write flags are switchable from write in to read out by changeover switches controlled by an access control unit for connection of the address and control inputs of the memories either to a write in control circuit or a read out control circuit. The access control unit can be set for operation at normal speed, which is the recording speed of the tape from which signals are read out, below normal speed or above normal speed. The read-out control circuit is synchronized by a synchronizing signal that contains a vertical scan frequency reference pulse. The several picture field memories are cyclically interchanged, written into and read out from. One of the picture field memories is read out while the others are available for write-in. The incoming error flags are passed on. Use is made of write flags and error flags to improve operation at speeds different from the recording speed.