Journal of the Society of Motion Picture Engineers (1930-1949)

Record Details:

Title:
Journal of the Society of Motion Picture Engineers
Date:
1930-1949
Publisher:
New York, N.Y. : The Society
Volume:
Journal of the Society of Motion Picture Engineers
Leaf #:
000232
Language:
English
Collection:
Technical Journals
Format:
Periodicals
Contributor:
Prelinger Library
Sponsor:
MSN
Coordinator:
Media History Digital Library
Description:
The Journal of the Society of Motion Picture Engineers (SMPE)Êdocuments the technological progress of the film industry, highlighting technical developments in production and exhibition. Of special interest are articles about special effects, theater practices, lighting, and the introduction of the 16mm format. Initially titled "Transactions of the Journal of the Society of Motion Picture Engineers."Digitized by the Prelinger Library and the Library of Congress Motion Picture, Broadcasting and Recorded Sound Division.
Date Added:
July 19, 2022
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1949 MAGNETIC RECORDING 229 Under most circumstances it is not necessary to utilize this feature, but it is available if needed. PEE AND POSTEQUALIZATION Pre and postequalization are employed to increase the signalto-noise ratio. Although the basic theory of operation of this method of noise reduction is identical whether it is applied to magnetic or to photographic recording, the magnetic medium requires somewhat different equalization for optimum results. Whereas with film recording the noise energy is predominantly in the high frequencies, u -flO 1+5 to Ul K 0 Id H 5 £-10 PRE 50 100 200 500 1000 2000 FREQUENCY IN CYCLES PER SECOND 5000 10000 Fig. 10 — Magnetic-recording pre-equalization curve. with magnetic recording, mainly because of the 6-decibel-per-octave equalization, the low frequencies usually contain the greater portion of the noise energy. Therefore, in addition to the normal photographic-type high-frequency equalization, some equalization is applied to the frequencies below 250 cycles. The resulting over-all pre-equalization characteristic is shown in Fig. 10; the postequalization is, of course, complementary to this curve, as shown. PERFORMANCE Flutter measurements indicate that the method of film propulsion used in this recorder, in which the recording head is located at the recording drum, produces a record that is somewhat better than a