1、SMPTE EG*12 94 W 8357403 OOOL5L4 5b9 SMPTE ENGINEERING GUIDELINE Control of Basic Parameters in the EG 12-1994 Revision of EG 12-1 986 3rL-1 “-“oc Manufacture of SMPTE Photographic and Magnetic Audio Test Films 1 Scope This guideline specifies and describes the basic con- trol parameters to be follo
2、wed in the production of SMPTE-distributed audio test films. 2 Normative reference The following standard contains provisions which, through reference in this text, constitute provisions of this guideline. At the time of publication, the edition indicated was valid. All standards are subject to revi
3、sion, and parties to agreements based on this guideline are encouraged to investigate the possibility of applying the most recent edition of the standard a indicated below. SMPTE RP 134-1994, Polarity for Analog Audio Magnetic Recording and Reproduction 3 Intended use of the test films 3.1 For the p
4、urpose of this guideline, photo- graphic and magnetic audio test films, as speci- fied in their parent documents, can be classified according to their use, as follows: 3.1.1 Operational The films are intended as tools for checking the nor- mal and correct operation of a piece of equipment. 3.1.2 Obj
5、ective The films are intended to be used as system- alignment tools for quantitative measurements and/or numerical (statistical) evaluation of deviations from established standard values of measurable equip- ment parameters. Page 1 of 3 pages 3.1.3 Subjective The products will be used for quick, ove
6、rall evaluation, or comparison of the qualitative characteristics of equipment. 4 Classes of inspection 4.1 Application of classes of inspection The SMPTE Engineering Department will determine the required class of inspection for each item specified in each test film document to ensure that all the
7、products supplied by SMPTE meet an AQL level so that substantially all the products meet the primary characteristics called for by the parent document. 4.2 Class 1: Calibrated. 4.3 Class 2: Each item to be 100% inspected. 4.4 Class 3: One unit of each 1 O in a production run to be inspected. 4.5 Cla
8、ss 4: Two units of each production run to be inspected. 5 Final product 5.1 All test films shall be made in accordance with specifications given in their parent docu- ment. 5.2 All test films shall be of splice-free stock unless the specifications state otherwise. 5.3 The base film stock shall be in
9、 accordance with the specifications given in the parent docu- ment. Copyright O 1994 by the SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartcdale Ave., White Plains, NY 10607 (91 4) 761 -1 1 O0 Approved February 8,1994 SMPTE EG*L2 94 W 8357LiOL OOOL515 YT5 EG 12-1994 6 Dimensional stab
10、ility 6.1 For test films to be magnetically recorded, the physical parameters of the film stock shall be stabilized before coating with magnetic oxide. This is usually accomplished by exposure to a constant temperature and humidity environment for a period of time prior to coating. Following coating
11、, a similar amount of time is allowed for the coating to dry under the same environmental conditions prior to recording. 6.2 Typical preconditioning before coating con- sists of maintaining the film for 10 days at a temperature of 20C 2 3C (68F 2 5.4“F) and at a relative humidity of 50% 2 10%. After
12、 coating, the environmental conditions for drying are the same as those for preconditioning. 6.3 For test films to be photographically recorded, the physical parameters of the film stock shall be stabilized before recording. This is usually accomplished by exposure to a con- stant temperature and hu
13、midity environment for a period of time prior to recording. 6.4 Typical preconditioning of film before photo- graphic recording consists of maintaining the film for 10 days at a temperature of 20C I 3C (68F f 5.4“F) and at a relative humidity of 50% 2 10%. This requirement is usually met by keep- in
14、g the film in its original sealed packaging at the specified temperature. 7 Sequence The test sections and segments shall be recorded on the film in such a manner that they replay from head to tail in the order corresponding to the sections and subsections of the parent document. full-coated film, t
15、his can be ensured by having one continuous gap at least the full width of the film; in the case of stripe-coated film or full-coated film recorded with separate records across the width, this can be ensured by the method noted in annex A. 8.2 Consistency of recorded polarity across the width of pho
16、tographic test films The recorded area, density, or other means of record- ing photographically shall have identical polarity in all the records, unless otherwise noted in the parent document. 8.3 The absolute polarity of recorded test signals for test films need not be controlled since the test sig
17、nals are sinusoids or noise having no polarity-reversal consequences. Specialized test films or film segments intended to standard- ize absolute polarity shall be recorded with the polarity shown in SMPTE RP 134. 9 Environmental conditions, winding, packaging and instructions 9.1 Environmental condi
18、tions of recording The films shall be recorded and packaged within the temperature and humidity limits specified in 6.2. 9.2 Winding and packaging 9.2.1 70-, 35-, and 16-mm materials shall be placed on cores of at least 3-in (75-rnm) diameter (to minimize core-set) with the tail end out and wound em
19、ulsion side in. 9.2.2 All materials shall be wrapped in chemi- cally-neutral plastic bags and sealed in metal cans with self-adhesive tape designed to provide a moisture and vapor barrier. 8 Polarity of recordings 1 O Identification 8.1 Consistency of recorded polarity across the width of magnetic t
20、est films The recorded magnetic flux across the film width shall have identical polarity in all the records. In the case of Each test film and can shall be suitably identified to show the contents, serial number, and date of manu- facture. The film shall be identified on the head and tail leaders, a
21、nd the can shall be labeled. Page 2 of 3 pages SMPTE EG*L2 9Y W 8357LiOL 000151b 331 EG 12-1 994 Annex A (informative) Additional data A constant polarity relationship of the recorded flux, as recorded by a multiple-track recording head, can be ensured if the individual coils of the recording head a
22、re similar and are assembled in the same manner. The relationship is accomplished by connecting the winding in series so that the end of each coil is connected to the beginning of the next coil, thus maintaining a consistent direction of winding. This relationship can also be accomplished with a parallel-type connection if the corresponding beginning leads are con- nected together and the corresponding ending leads are connected together and the direction of each winding is kept consistent with other coils. Page 3 of 3 pages
