1、SMPTE 18M-2003 Revision of ANSIISMPTE 18M-1996 SMPTE STANDARD for Television Analog Recording - 1-in Type C - Basic System and Transport Geometry Parameters Page 1 of 4 pages 1 Scope This standard specifies the general video record system, video pole tip locations, scanner parameters, scanner-guide
2、locations, tape tension, and test conditions for 1 -in type C helical-scan television analog recorders operating on the 52960 monochrome or NTSC color systems. 2 General specifications Tests and measurements made on the recorder to check the requirements of this standard shall be made under the foll
3、owing atmospheric conditions: Temperature for drum diameter: 20C * 1 “C Temperature for other tests: 20C f 1 “C Relative humidity: (50 * 2)Yo Barometric pressure: 86 kPa to 106 kPa Conditioning before testing: 24 h 3 Video and sync record system 3.1 Exactly one field of video shall be recorded durin
4、g each scanner revolution. The record shall be divided into two parts, video and sync. The users attention is called to the possibility that compliance with this standard may require use of an invention covered by patent rights. 3.2 The video record shall contain all active picture lines and suffici
5、ent vertical sync information for playback synchronization. Information not contained in the video record is defined as the vertical-interval dropout (see SMPTE 19M). 3.3 The sync record shall contain a number of horizontal lV lines during the vertical interval including those of the vertical-interv
6、al dropout and sufficient overlap of information for playback switching (see SMPTE 19M). The users attention is called to the possibility that compliance with this standard may require use of an invention covered by patent rights. By publication of this standard, no position is taken with respect to
7、 the validity of this claim or of any patent rights in connection therewith. The patent holder has, however, filed a statement of willingness to grant a license under these rights on reasonable and nondiscriminatory terms and conditions to applicants desiring to obtain such a license. Details may be
8、 obtained from the publisher. No representation or warranty is made or implied that this is the only license that may be required to avoid infringement in the use of this standard. Copyright 02003 by THE SOCIETY OF Approved February 7,2003 MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartsdale Ave
9、., While Plains. NY 10607 (914) 761-1100 SMPTE 18M-2003 3.4 Recording of the sync record shall be optional; however, no other information shall be recorded in the allotted tape area. 4 Scanner pole tips 4.1 There shall be six circumferential pole tip locations as shown in figure 1, top-view. When an
10、 operational pole tip is not required, a suitable nonfunctional tip shall be placed in the same location. 4.2 Each tip projection shall be 0.06 mm * 0.03 mm, measured from the outer surface of the upper drum to the end of the pole tip. 4.3 The axial distance between each video head pole tip and its
11、associated sync head pole tip shall be as shown in figure 1, side view. A TOP VIEW I 1O0OS /! 12O02Oo5/ I SYNC ViDEO I I UPPER RECORD / REPODUCE DRUM TPE I ROJATI ON TRAVEL ! I= 134.62 134.62 UPPER DRUM LOWER DRUM-“ 134.580 Di A 134.562 SIDE VIEW Figure 1 - Pole tip locations and drum dimensions Pag
12、e 2 of 4 pages - SMPTE 18M-2003 5 Scanner guides 5.1 Location of the tape entrance and exit guides shall provide a tape wrap angle such that the video record vertical-interval dropout is 10.00 horizontal lines f 0.25 horizontal lines due to loss of head-to-tape contact, with no electronic switching
13、of the recording signal. Start and end of the vertical-interval dropout shall be measured at the half-amplitude points of the rf envelope. 5.2 The helix angle formed by the scanner and all associated tape guides shall be 2“3529“1 2“. 6 Drum diameter and tape tension Effective drum diameter, tape ten
14、sion, helix angle, and tape speed completely determine the video record track angle. Different methods of design and/or minor variations in drum diameter and tape tension will produce equivalent recordings for interchange purposes. Values and operating conditions specified in this standard will prod
15、uce the reference value of track angle (see SMPTE 19M). 6.1 The actual upper drum diameter shall be 134.620 mm + 0.018 mm - 0.000 mm. 6.2 The actual lower drum diameter shall be 134.580 mm + 0.000 mm - 0.01 8 mm. 6.3 The upper drum section shall rotate in synchronism with the video tips. 6.4 The cen
16、ter span tape tension shall be 1.7 N f 0.3 N. 7 Definitions The following definitions of terms ensure correct understanding of this standard: 7.1 center span tension: A calculated value of tape tension at a point midway between tape entrance and exit guides of the scanner in a video tape recording s
17、ystem. I 7.2 drum: A right circular cylinder around which tape is at least partially wrapped in order to form the head- to-tape interface of a video tape recording system. 7.3 effective drum diameter: A value of drum diameter which when used in theoretical calculations will correspond to the actual
18、video record produced in a helical-scan video tape recording system. The effective value is equal to or greater than the actual drum diameter. i 7.4 helix angle: The angle formed between the path of the rotating pole tips and the tape reference edge- guiding system on the scanner of a helical-scan v
19、ideo tape recording system. 7.5 lower drum: That part of the drum in a helical-scan video recording system which contacts the reference edge of the tape and usually contains tape-guiding elements (see SMPTE 19M). 7.6 scanner: A mechanical assembly containing a drum, rotating pole tips, and tape-guid
20、ing elements used to record and reproduce video tape recordings. 7.7 track angle: The angle of the recorded video track with respect to the reference edge of the tape in a 7.8 upper drum: That part of the drum in a helical-scan video tape recording system which does not contact the reference edge of
21、 the tape (see SMPTE 19M). helical-scan video tape recording (see SMPTE 19M). .- Page 3 of 4 pages SMPTE 18M-2003 Annex A (informative) Bibliography ANSVSMPTE 24M-1996, Television Recording - 1-in Reels ANWSMPTE 25M-1995, Video Recording - 1-in Magnetic Recording Tape SMPTE 19M-2003, Television Anal
22、og Recording - 1 -in Type C - Records SMPTE 20M-2003, Television Analog Recording - 1 -in Type C Recorders and Reproducers - Longitudinal Audio Characteristics SMPTE RP 85-1999, Tracking Control Record for 1-in Type C Helical-Scan Television Tape Recording SMPTE RP 86-1991 (R1995), Video Record Parameters for 1-in Type C Helical-Scan Television Tape Recording Page 4 of 4 pages
