1、SMPTE RECOMMENDED PRACTICE I Specifications for Flutter Test Film for 35-mm Studio Audio Reproducers, Magnetic Type RP 75-2002 Revision of RP 75-1997 Page 1 of 2 pages 1 Scope This practice specifies a test film for determining the presence of flutter in 35-mm motion-picture studio magnetic audio re
2、producers operating at 96 perforations per second or approximately 90 fi (27 m) per minute for use with one-, three-, four-, and six-track audio systems. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this practice. A
3、t the time of publication, the editions indicated were valid. All standards are subject to revision, and patties to agreements based on this practice are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. AES 6-1982, Method for Measurement
4、 of Weighted Peak Flutter of Sound Recording and Reproducing 1 Equipment AES 7-1982 (R1992), Method of Measuring Recorded Flux of Magnetic Sound Records at Medium Wavelengths ANSI/SMPTE 86-1996, Motion-Picture Film - Magnetic Audio Records - Two, Three, Four and Six Records on 35-mm and One Record o
5、n 17.5-mm Magnetic Film ANSVSMPTE 139-1996, Motion-Picture Film (35-mm) - Perforated KS SMPTE 223M-2001 I Motion-Picture Film - Safety Film 3 Test film signal 3.1 Frequency The audio record shall reproduce at a frequency of 3150 Hz k 25 Hz when the linear speed of the film is 96 perforations per sec
6、ond or approximately 90 ft (27 m) per minute (18 in or 46 cm per second). 3.2 Distortion The total harmonic distortion of the recorded signal shall not exceed 0.2%. 3.3 Audio record I The audio record shall be recorded so that it extends from one edge of the film to the other. Copyright O 2002 by TH
7、E SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartsdale Ave., White Plains, NY 10607 (914) 761-1100 Approved July 26,2002 RP 75-2002 3.4 Recorded level The flutter test tone shall be not less than 6 dB down from the equivalent reference level of 1 kHz at 185 nanowebers per meter after
8、correct equalization of 35 ps. 3.5 Flutter The weighted peak flutter of the audio record shall not exceed f 0.4% when measured in accordance with AES 6. 3.6 Azimuth The azimuth of the audio record shall be 90“ k 3 to the reference edge of the film. 4 Film stock 4.1 The film stock shall be full-coat,
9、 splice-free, safety type in compliance with SMPTE 223M. 4.1.1 Test films made on low-shrinkage, triacetate base shall be cut and perforated in accordance with long-pitch dimensions specified in ANSI/SMPTE 139. 4.1.2 Test films made on polyester base shall be perforated in accordance with short-pitc
10、h dimensions specified in ANSI/SMPTE 139. 4.2 The film stock shall be conditioned for 10 days at 20C f 3C (68F I5.4“F) at a relative humidity of 50% +- 10% prior to recording. 4.3 The film shall be recorded and packaged within the temperature and humidity limits specified in 4.2. The recorded film s
11、hall be packaged in a metal can and sealed either with a low-moisture - _-_ - - L ?I?*. . -I - -A! - I - - errneamiiry piasric rape or ibric iap having misir barrier. 5 Identif cation Each test film shall be identified by a suitable identification marking. 6 Calibration 6.1 Flux Theshort circuit flu
12、xonthetestfilmshall bedetermined 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 accuracy of f 0.1 dB over the bandwidth 31.5 Hz to 16 kHz. 6.3 Method The test film shall be calibrated on a reproducing head made in accordance with ANSVSMPTE 86. NOTE - A test film made in accordance with this practice is available from the Society of Motion Picture and Television Engineers. Page 2 of 2 pages
