1、 STD-SMPTE EG 20-ENGL 1777 111 8357401 00028bi 724 EG 20-1997 SMPTE ENGINEERING GUIDELINE Revision of EG 20-1993 Tape Transport Geometry Parameters for 19-mm Type D-2 Composite Format for Television Digital Recording Page 1 of 5 pages 1 Scope This guideline describes two feasible examples of mechani
2、cal design and test conditions for achieving the record dimensions specified in ANSIISMPTE 245M. The parameters are for reference purposes only. 2 General specifications 2.1 Dimensions are in the metric system. 2.2 Tests and measurements made on the recorder to check the requirements of this guide-
3、line shall be made under the following atmospheric conditions: Temperature 20C f 1C Relative humidity (50 f 2)Yo Barometric pressure Conditioning of the 96 kPa k 10 kPa Not less than 24 hours recorder before testing 3 Scanner specifications 3.1 The effective drum diameter, tape tension, helix angle,
4、 and tape speed taken together determine the track angle. Different methods of design andlor variations in drum diameter and tape tension can produce equivalent recordings for interchange purposes. 3.2 Two possible design examples are shown in table 1 and table 2, and figure 1 and figure 2. 3.3 The
5、longitudinal head locations and tape wrap for design I are shown in figure 3. 3.4 The longitudinal head locations and tape wrap for design 2 are shown in figure 4. Copyright O 1997 by the SOCIETY OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Hartsdaie Ave., White Plains, NY 10607 Approved Septem
6、ber 18. 1997 (914) 761-1100 STD.SMPTE EG 20-ENGL 1797 8357403 0002b5 bb EG 20-1 997 Table 1 - Pole tip relationships Parameters Design 1 Design 2 Relevant figures Minimum number of pole tips Angular relationship HI - H2 (degrees) H3 - H4 HI -H3 Vertical displacement HI - H2 Maximum tip projection (p
7、m) (mm) H3 - H4 Figure 1 Figure 2 4 4 4.22 3.56 4.22 3.56 180.00 180.00 0.0373 0.0376 0.0373 0.0376 50 50 Table 2 -Scanner design parameters I Parameters Desian 1 Desian 2 Scanner rotation speed (rps) 90/1.001 i) 90/1.001 l) Number of tracks per rotation 4 4 Actual drum diameter Upper (mm) Lower (mm
8、) Center span tension (N) Helix angle (degrees) Effective wrap angle (degrees) Scanner circumferential speed (m/s) Overwrap leading (degrees) trailing (degrees) 96.444 I 0.005 96.444 10.005 96.434 f 0.005 96.434 10.005 0.7 f 0.1 0.7 IO.1 6.1592 6.1592 178.2 178.2 27.3 27.3 5 4.8 5 4.8 1 Record head
9、track width 41-45 pm 42 Pm tYP 1 )I ,001 = 60/59.94 Page 2 of 5 pages STD-SMPTE EG 20-ENGL 1977 M 83574011 00028bb 5T7 II L -A- -Y -, LOWER DRUM - L EG 20-1 997 H2. H4 TOP EDGE OF GAP t TAPETRAVEL / ,i, 1 H3 ,POLE TiP ROTATION II TDTALWRAP H14i4. WLE TIPS c _I., UPPER DRUM LOWER DRUM I I Figure 1 -S
10、canner configuration for design 1 Figure 2 - Scanner configuration for design 2 Page 3 of 5 pages STD-SMPTE EG 20-ENGL L777 8357403 UU28b7 433 EG 20-1997 178.t0 I f I EFF EtTi VE PNGLE 93.3 i PROCRAM TOP VIEW 5.066 4 / - - 3- START OF 6. i592* c I III l t-w-+- 1 UNWRAPPED, VIEWED MAGNETIC COATING SI
11、DE Figure 3 - Longitudinal head locations and tape wrap for design 1 Page 4 of 5 pages STD-SMPTE EG 20-ENGL 1997 D 8357403 00028b8 37T = EG 20-1997 / TOTAL h WRAP - u 93.3 TOP VIEW PROGRAM REFERENCE POINT 6.1592. 5.066 93.3 START OF I 1 It L+ CONTROL TRPCK HEAD 98.4 107.66 UNWRAPPED, VIEWED MAGNETIC
12、 COATING SIDE Figure 4 - Longitudinal head locations and tape wrap for design 2 Annex A (informative) Bibliography ANSIISMPTE 226M-1996, Television Digital Recording - 19-mm - Tape Cassettes ANSIISMPTE 247M-1993, Television Digital Recording - 19-mm Type D-2 Composite Format - Helical Data and Contr
13、ol Records ANSIISMPTE 244M-1995, Television - System MINTSC Composite Video Signals - Bit-Parallel Digital Interface ANSIISMPTE 248M-1993, Television Digital Recording - 19-mm Type D-2 Composite Format - Cue Record and Time andcontrol Code Record SMPTE EG 21-1997, Nomenclature for Television Digital Recording of 19-mm Type D-I Component and Type D-2 Composite Formats ANSIISMPTE 245M-1993, Television Digital Recording - 19-mm Type D-2 Composite Format -Tape Record ANSIISMPTE 246M-1993, Television Digital Recording - 19-mm Type D-2 Composite Format -Magnetic Tape Page 5 of 5 pages
