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. 05, 1983
Filed:
Jan. 12, 1981
Michael G Lee, Redmond, WA (US);
Indal Corp., Bellevue, WA (US);
Abstract
A system for the control and synchronization of magnetic tape and filmstrip in an audio-visual projector. Film is advanced by means of recorded advance tones on the magnetic tape which are detected by a tone detector to generate an advance pulse. An advance counter is incremented responsive to each advance pulse and decremented as the film advances each frame. The output of the advance counter actuates a film-advance mechanism unless the contents of the counter are zero, so that synchronization is maintained even if the rate at which the advance pulses occur exceeds the operating speed of the film-advance mechanism. Means are provided to automatically synchronize the tape and film at predetermined locations by optically sensing markers affixed to the tape and film. The system may also advance the tape independently of the film in either a fast-forward or a regular-speed mode or it may advance the film independently of the tape.