1、SMPTE RECOMMENDED PRACTICE RP 76-2002 Revision of RP 76-1997 Specifications for Flutter Test Film for 16-mm Audio Reproducers, Magnetic Type Page 1 of 2 pages 1 Scope This practice specifies a test film for determining the presence of flutter in 16-mm motion-picture magnetic audio reproducers operat
2、ing at approximately 36 ft (11 m) per minute. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions in this practice. At the time of publication, the editions indicated were valid. All standards are subject to revision, and par
3、ties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. AES 6-1 982, Method for Measurement of Weighted Peak Flutter of Sound Recording and Reproducing Equipment AES 7-1982 (R1992), Method of Measur
4、ing Recorded Flux of Magnetic Sound Records at Medium Wavelengths ANSVSMPTE 109-1998, Motion-Picture Film (16-mm) - Perforated 1 R SMPTE 97-1 999, Motion-Picture Film (1 6-rnm) - 200-Mil Edge-Position Magnetic Audio Record SMPTE 223M-2001, Motion-Picture Film - Safety Film 3 Test film signal 3.1 Fre
5、quency The audio record shall be an original recording which will reproduce at a frequency of 3150 Hz k 25 Hz when the linear speed of the film is 24 perforations per second or approximately 36 fi per minute (7.2 in or 183 mm per second). 3.2 Distortion The total harmonic distortion of the recorded
6、signals shall not exceed 0.5%. 3.3 Audio record The audio record shall be recorded so that it extends from the perforations on one side of the film to the opposite edge, or from one edge of the film to the other. Copyright O 2002 by THE SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Harts
7、dale Ave., White Plains, NY 10607 (914) 761 -1 1 O0 Approved July 26,2002 RP 76-2002 3.4 Record level The flutter test tone shall not be more than 10 dB down from the equivalent reference level of 400 Hz at 185 nanowebers per meter after correct equalization of 70 ps. 3.5 Flutter The weighted peak f
8、lutter of the audio record shall not exceed f 0.1% when measured in accordance with AES 6. 3.6 Azimuth The azimuth of the audio record shall be 90 f 3 to the reference edge of the film. 4 Film stock 4.1 The film stock shall be full-coat, splice-free, and of the low-shrinkage, safety type in complian
9、ce with SMPTE 223M. 4.2 Test films shall be made on a base cut and perforated in accordance with ANSVSMPTE 109. 4.3 The film stock shall be conditioned for 1 O days at 20C f 3C (68OF f 5.4“F) at a relative humidity of (50 f 1 O)% prior to recording. 4.4 The film shall be recorded and packaged within
10、 the temperature and humidity limits specified in 4.3. The recorded film shall be packaged in a metal can and sealed either with a low-moisture permeability plastic tape or a fabric tape having a moisture barrier. 5 Identification Each test film shall be identified by a suitable identification marki
11、ng. 6 Calibration 6.1 Flux The short circuit flux shall be determined by means of the calibrated short-gap ferromagnetic core reproducer technique. This technique is described in AES 7. 6.2 Level The signal level specified in 3.4 shall be measured with an rms voltmeter calibrated in decibels with an
12、 accuracy of f 0.1 dB over the bandwidth 31.5 Hz to 16 kHz. 6.3 Calibration The test film shall be calibrated on a reproducing head made in accordance with SMPTE 97. NOTE-A test filmconforming to this practice isavailable from the Society of Motion Picture and Television Engineers. Page 2 of 2 pages
