Filtering Factors of the Magnetic Drive

R. O. Drew, E. W. Kellogg

A laboratory model of a magnetic-drive film-phonograph was modified so that speed fluctuations of large and measurable magnitude and of frequencies ranging from 1/2 to 7 cycles could be introduced either into the sprocket rotation or the magnet rotation. The resulting speed variations at the drum were determined by means of a “wowmeter.” The large ratios of flutter reduction indicated by these measurements show in part why the magnetic drive gives unsurpassed film motion.

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Published
1940-08
Content type
Original Research
DOI
10.5594/J10057