The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 17, 1984
Filed:
Sep. 21, 1981
Michael F Berger, Fort Worth, TX (US);
Tandy Corporation, Fort Worth, TX (US);
Abstract
Data synchronization apparatus for a 1500 baud computer-audio frequency magnetic tape recorder interface is disclosed. The synchronization apparatus automatically detects bit cell boundaries and synchronizes at both the bit level and the byte level even if the audio waveform as read from the tape is inverted, as is the case with some tape recorders. Synchronization is performed by squaring the audio waveform and measuring two successive time intervals occurring between three successive positive-going transitions and subtracting the resulting measurements. If the calculated difference is less than a predetermined amount, positive-going transitions of the waveform are selected as bit cell boundaries. If, on the other hand, the calculated difference is greater than the predetermined amount, negative-going edges are selected as bit cell boundaries. Synchronization is achieved on a byte level by shifting incoming data into a first-in/first-out buffer and examining the stored data for a predetermined bit pattern.