1979 年 3 巻 16 号 p. 13-18
This is a technical report of 16-mm two-track photographic sound reproducing projector developed by Hokushin Electric Works, Ltd.in Mar., 1979. It is one of the projectors of this kind completed at an early stage in this country. The Japan Motion Picture Equipment Industrial Association (JMEIA), of which Hokushin Electric Works is one of the members, started in January, 1979 to draft their own standards for the sound records by referring to DRAFT PROPOSAL "Dimensions of two-track photographic sound records on 16-mm motion-picture prints" shown in ISO/TC36 409,and formulated JMEIA Standard JMS511-1979 in July this year. The 16-mm two-track photographic sound reproducing projector developed by Hokushin not only meets the requirements of the JMS511,but also has such characteristics as those stated below. The 16-mm two-track sound reproducing projectors to be manufactured hereafter by Hokushin will have these specifications or better. Frequency Characteristics : 50-7000Hz Within 2dB at each channel. 30-10000Hz Available. Crosstalk : Less -40dB at 80% modulation. 0dB. -33dB at 100% modulation. Distortion : Within 3% at each channel. Signal to Noise Ratio : Over 50dB. Measured by JIS (Japan Industrial Standard) measuring method. Dolby noise reduction off. (Characteristics common to ordinary projectors have been left out.) Signal test films and hearing test films used for the examination of the projector were made by us in cooperation with Aoi Studio Co., to whom we wish to extend out thanks for their assistance. We also express our appreciation to Dolby Laboratory ; the use of N.R. System (Type A) furnished by the laboratory helped to reduce film noise considerably.