A 16mm Projector for Operation with a Television Film-Chain on a Partial-Storage Basis

Edwin C. Fritts

This paper describes the modification of a 16mm television projector — now in service with the iconoscope tube on a full-storage basis — for use with the vidicon camera tube on a partial-storage basis. This makes available, for the reproduction of film in a television system, the advantages of the vidicon tube for black-and-white film and makes it possible to project color film into a three-vidicon chain when it becomes available. The requirements associated with flicker are detailed, and the sequence of events that is necessary for partial storage is compared with that required for full storage. It is shown that a 2–3 system separates the pulldown by the required integral number of television fields and yet maintains the usual 2½ to 1 ratio between television fields and motion-picture frames. Further account is taken of the phasing necessary between the pulldown motor and the shutter motor, and the changes required in the design of the shutter. Under the heading of mechanical details, there is a description of the accelerator that provides the 2–3 sequence, and a discussion of the features provided to ameliorate the conditions introduced by more complicated accelerations and greater noise. In conclusion, the paper cites the results of a durability test and reviews the features of the installation and maintenance of the 2–3 system.

Print ISSN
Published
1955-10
Content type
Original Research
DOI
10.5594/J14014