Method of cross-checking data block identification signals of data reproduced from a magnetic tape record

US4931885A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

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

Key dates

• Filing date: May 24, 1988
• Grant date: Jun 5, 1990
• Expiry date: May 24, 2008

Classification

• Technology area (CPC G): Physics
• CPC primary: G11B2220/90
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

Data blocks recorded on oblique tracks on magnetic tape are preceded by synhronizing signals and block identification signals. The serial data identification signals are converted to 8-bit parallel form and then are split between an undelayed channel and a channel delayed by one data block. Under control of a sync detector the parallel data are made to correspond with data words and are then decoded for comparison of the block numbers. Since the block numbering is consecutive, the delayed decoded block number is incremented by one for comparison. When a positive comparison is obtained the block number of the delayed decoded signals is made available to identify the data block. A counter in a so called fly wheel circuit assures provision of a new block start signal if a synchronizing signal is missed and prevents the timing of the circuit from being put off by a false detection of a synchronizing signal. A block identification output appears only if its block number is in sequence.