1、INTERNATIONAL STANDARD Second edition 1994-08-01 Cinematography - Audio records on 70 mm motion-picture release prints with magnetic stripes - Recorded characteristic Cinema tographie - Enregis tremen ts sonores sur copies d exploitation sur film cin6matographique 70 mm 9 pistes magn is a time const
2、ant with a value of 3 180 1s; th is a time constant with a value of 35 ps; CO is a constant calculated to make Lo = 0 at the reference frequency of 1 000 Hz. NOTES 1 A frequency response curve may be conveniently de- fined as proportional to the impedance curve of a resistance-capacitance network ha
3、ving stated time con- stants. Such a network is not intended as a recommended electrical circuit. 2 It has been shown that a low-frequency time constant of infinity should be used for best headroom versus fre- quency of the medium. It is recognized, however, that it is necessary for the immediate fu
4、ture to continue to add low- frequency pre-emphasis of 3 180 ps because much theatre equipment cannot meet the tolerances of this International Standard when using a time constant of infinity. IS0 8590: 1994(E) Table 1 - Approximate values of the recorded relative magnetic flux Frequency, f LB Toler
5、ances Hz dB dB 20 w3 25 7,19 31,5 40 50 5,66 4,29 3,21 63 2,32 80 I,63 100 I,16 125 0,84 160 0,59 200 0,45 250 0,35 315 0,28 400 0,23 500 0,19 630 0,14 800 0,08 I 000 0 I 250 -0,12 1600 - 0,31 2 000 - 0,57 2 500 - 0,95 3 150 - I,51 4 000 - 2,29 5 000 - 3,25 6300 - 4,46 8 000 - 5,93 IO 000 - 7,47 125
6、00 - 9,13 16000 - II,07 +3,0 -10.0 +3,0 -8.0 +3,0 -6,0 +2,0 -4,0 +l,O -l,o +1,5 -2,0 +2,0 -2,5 +2,0 -3,5 IS0 8590: 1994(E) -8 -12 20 40 80 160 315 630 I,25 2,s 5 IO 20 . T . . T d Hz kHz Figure 1 - Approximate values of the recorded relative magnetic flux -6 -8 - 10 -12 Equalized dB values of table
7、1 -20 40 80 160 315 630 l,25 2,s 5 10 20 c 4 . 4 v T Hz kHz Figure 2 - Tolerances This page intentionally left blank This page intentionally left blank IS0 8590: 1994(E) ICS 37.060.20 Descriptors: cinematography, motion-picture film, characteristics. motion-picture film 70 mm, sound recording, magnetic recording, recording Price based on 3 pages
