GB1535723A - Audio-visual apparatus - Google Patents

Abstract

1535723 Telecine apparatus COLOUR CASSETTES Ltd 2 Jan 1976 [4 Oct 1974 (2) 15 Jan 1975] 43192/74, 43193/74 and 1772/75 Heading H4F The intermittent drive which causes the movement of a film strip through a film gate is controlled by a control signal read from a recording medium, e.g. a magnetic tape, which also carries audio signals. The film in the gate is scanned to provide a video signal which may be displayed on a television receiver, the audio signals being passed to the audio circuit of the receiver. As disclosed the film in the gate is scanned by a raster developed on the face of a c.r.t. scanner. The position of the raster on the c.r.t. face may be adjusted so that a selected region of the film is scanned. The size of the raster may also be varied, or alternatively a zoom lens used to vary its effective size. Light passing through the film is detected by three photomultipliers associated with colour filters or dichroic mirrors, the resulting colour signals being passed to a colour television receiver. The audio signals from the recording medium playback unit are fed to the receiver. The control signals, which may be on the audio track or on a separate track, are passed to a drive control unit and to a sync unit. The sync unit provides outputs to the receiver and the c.r.t. scanner. The control unit causes the film to be advanced by one frame when required. The scanner is blanked during film movement. The sync unit may be dispensed with if the receiver can itself provide sync signals derived from a received broadcast signal. Movement of the film may be sensed by photoelectric or mechanical means whose output passes to the control unit. When so commanded by the playback unit the control unit attempts to stop the film. If the attempt is unsuccessful repeated attempts are made until either a signal is received from the film movement sensor or a preset number of attempts has been made. In the latter case a stop command is passed to the playback unit.