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Accurate Coded Timing-Light Generator

1965; Society of Motion Picture and Television Engineers; Volume: 74; Issue: 4 Linguagem: Inglês

10.5594/j06044

0361-4573

Roger Boy de la Tour,

CCD and CMOS Imaging Sensors

Photographic techniques are extremely useful in the study of fast phenomena or transient conditions. In such a study, it is necessary to know precisely the time elapsed during the different phases of the phenomenon. If more than one highspeed camera is used, it is important to correlate the time indications for all cameras, so that simultaneous photographs can be assembled. The easiest way to record time is to mark it on one edge of the film by means of a time-coded light. An accurate coded timing-light generator, giving a precision of a fraction of a millisecond, has been built and is described in this paper. It is capable of coding many cameras simultaneously at distances of many hundreds of feet. — The master unit is triggered by a crystal-controlled oscillator. Transistorized multivibrators generate the timing for the length of the different pulses indicating the seconds, the tenths, hundredths and thousandths of seconds. A transistorized switch applies 350 v to a NE 51 H (General Electric) neon bulb. Slave units are used at each camera location; they can work on dry batteries and are fully transistorized. The complete system is composed of the above decimal system, marking one edge of the film, and of a real-time digital master unit connected to the real-time slave units and lamps that mark the opposite edge of the film.