EN ISO IEC 9661-1995 en Information Technology - Data Interchange on 12 7 mm Wide Magnetic Tape Cartridges - 18 Tracks 1 491 Data Bytes per Millimetre《信息技术 在12 7 mm宽盒式磁带上的数据交换 18磁道.pdf
《EN ISO IEC 9661-1995 en Information Technology - Data Interchange on 12 7 mm Wide Magnetic Tape Cartridges - 18 Tracks 1 491 Data Bytes per Millimetre《信息技术 在12 7 mm宽盒式磁带上的数据交换 18磁道.pdf》由会员分享,可在线阅读,更多相关《EN ISO IEC 9661-1995 en Information Technology - Data Interchange on 12 7 mm Wide Magnetic Tape Cartridges - 18 Tracks 1 491 Data Bytes per Millimetre《信息技术 在12 7 mm宽盒式磁带上的数据交换 18磁道.pdf(62页珍藏版)》请在麦多课文档分享上搜索。
1、 STD-BSI BS EN ISO/IEC SbbL-ENGL LSS7 Lb24bb9 ObZbB88 57b BRITISH STANDARD Information technology - Data interchange on 12,7 mm wide magnetic tape caxtridges - 18 tracks, 1491 data bytes per millimetre u rn * The European Standard EN ISO/IEC 9661 : 1995 has the status of a British Standard ICs 35.22
2、0.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW _ - - _- - BS EN ISOAEC 9661 : 1997 STD*BSI BS EN ISO/IEC SbbL-ENGL 1997 Lb24bb9 ObZb889 402 direction of the DISC Board, was published under the authority of the Standards Board and comes ina effect on 15 July 1997 Amd. No.
3、 BS EN ISO/EC 9661 : 1997 Da Text affected National foreword This British Standard is the English language version of EN ISOLEC 9661 : 1995. It is identical with ISO/IEC 9661 : 1994. It supersedes BS 7062 : 1989 which is withdrawn. The UK participation in its prepamtion was entrusted to Technicai Co
4、mmittee IST/4, Magnetic and optid media for digital data, which has the responsibility to: - aid enquirem to understand the text; - present to the responsible internationaUEuropean committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed - monitor re
5、lated internationd and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement intemational or European pubiications referred to in this document may
6、 be found in the BSI Standards Catalogue under the section entitled Inteniational Stanch- id R to 5 x lo9 S for backcoated tapes. I l V V F F Figure 2 - Position of test piece over two semi-circular electrodes When mounting the test piece, make sure that no conducting paths exist between the electro
7、des except that through the coating under test Note - Particular attention should be given to keeping the surfaces clean. 6.14 Tape durability This International Standard does not specifi parameters for assessing tape durability. However, a recommended procedurr: is described in annex D. 6.15 Inhibi
8、tor tape This International Standard does not specify parameters for assessing whether or not a tape is an inhibitor tape. However, annex B gives further information on inhibitor tapes. 6 - - STD-BSI BS EN ISO/IEC SbbL-ENGL L777 Lb24bb7 ObZb904 547 W EN ISO/IEC 9661 : 1995 6.16 Tape abrasivity Tape
9、abrasivity is the tendency of the tape to wear the tape transport. The length of the wear pattern on a wear bar shall not exceed 56 pm when measured as specified in annex C. 6.17 Pre-recording condition Prior to recording data or to testing, the tape shall have been erased using alternating magnetic
10、 fields of decaying levels (anhysteretic process) to ensure that the remanent magnetic moment of the recording surface does not exceed 20 % of the maximum remanent magnetic moment. Annex E specifies the method of measurement. In addition no low density transitions shall be present on the tape. 6.18
11、Magnetic recording characteristics The magnetic recording characteristics shall be as defined by the testing requirements given below. When performing these tests, the output or resultant signal shall be measured on the same relative pass for both a tape calibrated to the Master Standard Reference T
12、ape and the tape under test (read-while-write or first forward-rca-pass) on the same equipment. The following conditions shall apply to the testing of ail magnetic recording characteristics, unless otherwise stated: - tapecondition : pre-recording condition - tapespeed : not greater than 2.5 m/s - r
13、ead-wxk : within the Written track - azimuth alignment - write-gaplength : 1,4 pm f 0.2 pm - write head saturation density - tapctension : 2.2 N f 0,2 N - recording current : test recording current 6.18.1 Typical field The typicai field of the tape shall be between 90 % and 110 % of the reference fi
14、eld. Traceability to the reference field is provided by the calibration factors supplied with each Secondary Standard Reference Tape. : not greater than 6 between the mean write transitions and the read gap : 0,34 T .t 0,03 T 6.183 Signai amplitude The average signal amplitude at the physical record
15、ing density of 972 ftpmm shall be between 70 % and 140 96 of the standard reference amplitude. Traceability to the standard reference amplitude is provided by the calibration factors supplied with each Secondary Standard Reference Tape. 6.183 Resolution The ratio of the average signal amplitude at t
16、he physical recording density of 1 458 ftpmm to that at the physical recording density of 972 ftpmm shall be between 80 % and i20 96 of the same ratio for the Master Standard Reference Tape. Traceability to the resolution of the Master Standard Reference Tape is provided by the calibration factors s
17、upplied with each Secondary Standard Reference Tape. 6.18.4 Overwrite Overwrite is the ratio of the average signal amplitude of the residual of the fundamental frequency of a tone pattern after being overwritten at 972 ftpmm to the average signal amplitude of the 972 ftpmm signal. The average signal
18、 amplitude of the tone pattern is the peak-to-peak amplitude of the sinusoidal signal with equal rms power. 6.18.4.1 Requirement The overwrite for the tape shall be less than 120 % of the overwrite for the Master Standard Reference Tape. Traceability to the overwrite of the Master Standard Reference
19、 Tape is provided by the calibration factors supplied with each Secondary Standard Reference Tape. 7 STD.BS1 BS EN ISO/IEC SbbL-ENGL 1797 lb24bb9 Ob2b705 485 EN ISO/IEC 9661 : 1995 Record a tone pattern which shall be the following sequence of flux transitions: O O O O O 1 O O O O O where: a = 1,029
20、 pm a2 = 0,514 p Record a 972 ftpmm signal over the tone pattern. Measure the average signal amplitude of the residual of the fundamental frequency of the tone pattern (one sixth of the frequency of the 972 fpmm signal) and the average signal amplitude of the 972 ftpmm signai. Both amplitude measure
21、ments should be made using suitable filters. 6.18.5 Narrow-Band Signai-to-Noise Ratio (NB-SNR) The narrow-band signal-to-noise ratio is the average signal amplitude mis power divided by the average integrated (side band) nns noise power, and is expressed in dB. 6.18.5.1 Requirement The NB-SNR ratio
22、shail be equal to, or greater than, 30 dB when normalized to a track width of 410 pm. The normalization factor is dB(410) = dB(W) + 10 log 410/W, where W is the track width used when measuring dB(W). 6.1852 Procedure The NB-SNR ratio shall be measured using a spectrum analyzer with a resolution band
23、width (RBW) of 1 kXz and a video bandwidth (VBW) of 10 Hz. The tape speed shall be 762 ds for the frequencies specified below. The NB-SNR ratio shall be measured as follows: i) ii) Measure the read-signal amplitude of the 972 ftpmm signal, taking a minimum of 150 samples over a minimum length of tap
24、e of 46 m. On the next pass (read only) measure the rms noise power over the same section of tape and integrate the rms noise power (normalizing for the actual resolution bandwidth) over the range from 332 kHz to 366 MIz. For other tape speeds all the frequencies shall be linearly scaled. 6.19 Tapeq
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