1、INTERNATIONAL STANDARD IEC 60774-4 First edition 2002-07 Helical-scan video tape cassette system using 12,65 mm (0,5 in) magnetic tape on type VHS Part 4: S-VHS video cassette system ET-mode Reference number IEC 60774-4:2002(E)Publication numbering As from 1 January 1997 all IEC publications are iss
2、ued with a designation in the 60000 series. For example, IEC 34-1 is now referred to as IEC 60034-1. Consolidated editions The IEC is now publishing consolidated versions of its publications. For example, edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the base publication, the base publica
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7、ice Centre (see below) for further information. Customer Service Centre If you have any questions regarding this publication or need further assistance, please contact the Customer Service Centre: Email: custserviec.ch Tel: +41 22 919 02 11 Fax: +41 22 919 03 00INTERNATIONAL STANDARD IEC 60774-4 Fir
8、st edition 2002-07 Helical-scan video tape cassette system using 12,65 mm (0,5 in) magnetic tape on type VHS Part 4: S-VHS video cassette system ET-mode IEC 2002 Copyright - all rights reserved No part of this publication may be reproduced or utilized in any form or by any means, electronic or mecha
9、nical, including photocopying and microfilm, without permission in writing from the publisher. International Electrotechnical Commission, 3, rue de Varemb, PO Box 131, CH-1211 Geneva 20, Switzerland Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmailiec.ch Web: www.iec.ch E For pric
10、e, see current catalogue PRICE CODE Commission Electrotechnique Internationale International Electrotechnical Commission 2 60774-4 IEC:2002(E) CONTENTS FOREWORD 3 1 Scope 5 2 Normative references. 5 3 Terms and definitions 5 4 Applicable video cassette recorder 5 5 Applicable video cassette 5 6 Vide
11、o signal recording . 6 6.1 Main pre-emphasis characteristics 6 6.2 Clipping level 6 6.3 FM signal recording head current 6 6.4 Converted chrominance signal recording level 7 7 Cassette discrimination system 7 Figure 1 Compensation filter response for 525 line-60 field signals . 7 Figure 2 Pre-emphas
12、is frequency response for 525 line-60 field signals 8 Figure 3 Compensation filter response for 625 line-50 field signals . 9 Figure 4 Pre-emphasis frequency response for 625 line-50 field signals.1060774-4 IEC:2002(E) 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ HELICAL-SCAN VIDEO TAPE CASSETTE SY
13、STEM USING 12,65 mm (0,5 in) MAGNETIC TAPE ON TYPE VHS Part 4: S-VHS video cassette system ET mode FOREWORD 1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object
14、 of the IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, the IEC publishes International Standards. Their preparation is entrusted to technical committees; any IEC Nation
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16、(ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has represent
17、ation from all interested National Committees. 3) The documents produced have the form of recommendations for international use and are published in the form of standards, technical specifications, technical reports or guides and they are accepted by the National Committees in that sense. 4) In orde
18、r to promote international unification, IEC National Committees undertake to apply IEC International Standards transparently to the maximum extent possible in their national and regional standards. Any divergence between the IEC Standard and the corresponding national or regional standard shall be c
19、learly indicated in the latter. 5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with one of its standards. 6) Attention is drawn to the possibility that some of the elements of this International Stan
20、dard may be the subject of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 60774-4 has been prepared by TA 7: Moderate data rate storage media and equipment, of IEC technical committee 100: Audio, video and multimedia sys
21、tems and equipment. The text of this standard is based on the following documents: CDV Report on voting 100/433/CDV 100/498/RVC Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in acc
22、ordance with the ISO/IEC Directives, Part 3. IEC 60774 consists of several parts under the general title Helical-scan video tape cassette system using 12,65 mm (0,5 in) magnetic tape on type VHS: Part 1: VHS and compact VHS cassette system Part 2: FM audio recording Part 3: S-VHS 4 60774-4 IEC:2002(
23、E) The committee has decided that the contents of this publication will remain unchanged until 2006. At this date, the publication will be reconfirmed; withdrawn; replaced by a revised edition, or amended. A bilingual version of this publication may be issued at a later date.60774-4 IEC:2002(E) 5 HE
24、LICAL-SCAN VIDEO TAPE CASSETTE SYSTEM USING 12,65 mm (0,5 in) MAGNETIC TAPE ON TYPE VHS Part 4: S-VHS video cassette system ET mode 1 Scope This part of IEC 60774 is applicable to the S-VHS ET mode which records in S-VHS signal format on a VHS cassette. In this mode, several video signal system reco
25、rding parameters are switched so that the signal characteristics recorded on the VHS tape are equivalent to S- VHS recording on S-VHS tape. Cassettes recorded in the S-VHS ET mode can be played with the S-VHS-based playback system and the VHS equivalent that includes the SQPB function. This standard
26、 indicates the differences from IEC 60774-3 which covers only S-VHS. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced do
27、cument (including any amendments) applies. IEC 60774-3:1993, Helical-scan video tape cassette system using 12,65 mm (0,5 in) magnetic tape on type VHS Part 3: S-VHS 3 Terms and definitions For the purposes of this document, the terms indicated in IEC 60774-3, as well as the following, apply. S-VHS q
28、uasi-playback SQPB function to enable the playback of S-VHS tape with a VHS machine 4 Applicable video cassette recorder The S-VHS ET mode is applicable for 525 line-60 field and 625 line-50 field signal recording. A video cassette recorder comprising this recording system shall contain a recording
29、system complying with both the VHS video cassette system standard and the S-VHS video cassette system standard. The recording system relates to the SP and EP modes for 525 line-60 field and the SP mode only for 625 line-50 field signal recording. 5 Applicable video cassette The recording system appl
30、ies to video cassettes in compliance with VHS cassette and VHS-C cassettes. Recordings in the S-VHS ET mode are not to be made using S-VHS cassettes. 6 60774-4 IEC:2002(E) 6 Video signal recording Refer to IEC 60774-3. 6.1 Main pre-emphasis characteristics The main pre-emphasis response is compensat
31、ed by the following filter: 525 line-60 field signals: see table 1, figure 1 and figure 2; 625 line-50 field signals: see table 2, figure 3 and figure 4. Table 1 Compensation filter response for 525 line-60 field signals Frequency MHz Response dB 1,0 0,2 0,3 2,0 0,8 0,3 3,0 1,6 0,3 4,0 2,5 0,3 5,0 3
32、,4 0,3 Table 2 Compensation filter response for 625 line-50 field signals Frequency MHz Response dB 1,0 0,4 0,3 2,0 1,3 0,3 3,0 2,6 0,3 4,0 3,9 0,3 5,0 5,1 0,3 6.2 Clipping level White clipping level (from sync tip): 190 % 10 % (S-VHS specification; 210 % 10 %) Dark clipping level (from sync tip): U
33、nchanged (70 % 10 %) 6.3 FM signal recording head current For the FM carrier frequency band, the optimum recording current shall be set for the applicable video cassette tape. The optimum recording current is defined as that required in order to obtain the maximum playback output.60774-4 IEC:2002(E)
34、 7 6.4 Converted chrominance signal recording level A red lustre signal input is recorded so that the playback level of (fy 2fc) frequency spurious component is 20 dB to 25 dB with respect to the fy playback level. fy: Luminance signal centre frequency (6,5 MHz) fc: Converted chrominance sub-carrier
35、 frequency NOTE A red lustre signal should be referred to IEC 61041-1, 3.3 1 . 7 Cassette discrimination system The S-VHS ET mode shall be selectable only when a cassette in compliance with the VHS standard is inserted. Playback mode detection shall be functioned from the playback FM carrier frequen
36、cy. R C Output 0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 4,0 3,5 3,0 2,5 2,0 1,5 1,0 0,5 0 Response dB f MHz T = RC = 35 ns R = 1 k C = 35 pF IEC 1824/02 Figure 1 Compensation filter response for 525 line-60 field signals1 IEC 61041-1:1990, Non-broadcast video tape recorders Methods of measurement G
37、eneral, video (NTSC/PAL) and audio (longitudinal) characteristics. 8 60774-4 IEC:2002(E) Before compensation f Hz 10 k 100 k 1 M 10 M 0 2 4 6 8 10 12 14 16 Response dB After compensation IEC 1825/02 Figure 2 Pre-emphasis frequency response for 525 line-60 field signals60774-4 IEC:2002(E) 9 R C Outpu
38、t 0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 4,0 3,0 2,0 1,0 0 Response dB f Hz T = RC = 47,56 ns R = 820 C = 58 pF 5,0 6,0 IEC 1826/02 Figure 3 Compensation filter response for 625 line-50 field signals 10 60774-4 IEC:2002(E) Before compensation f Hz 10 k 100 k 1 M 10 M 0 2 4 6 8 10 12 14 16 Respons
39、e dB After compensation IEC 1827/02 Figure 4 Pre-emphasis frequency response for 625 line-50 field signals _ StandardsSurvey TheIECwouldliketoofferyouthebestqualitystandardspossible.Tomakesurethatwe continuetomeetyourneeds,yourfeedbackisessential.Wouldyoupleasetakeaminute toanswerthequestionsoverlea
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