1、 STD.SMPTE 250M-ENGL 377b = 8357403 0002598 3b4 SMPTE STANDARD for Television Analog Recording - V2-h Type M-2 - Tapes and Cassettes ANSIISMPTE 250M-1996 Revision of ANSIISMPTE 250M-1991 1 Scope Page 1 of 21 pages 4.3 Direction of particle orientation: Longitudinal direction of tape This standard sp
2、ecifies tapes and cassettes for the 1/2-in type M-2 helical-scan video tape recording system. 2 General specifications 2.1 Dimensions are in the metric system. 2.2 Tests and measurements for confirming the requirements of this standard shall be made un- der the following conditions unless otherwise
3、specified: 4-4 Coercivity: Class 1500 4.5 Light transmissivity: 5% or less (measured over the range of wavelengths 700 nm to 900 nm). 4.6 Total thickness: 13.5 pm I 0.5 pm 4.7 Width: 12.65 mm rC 0.01 mm 4.8 Width fluctuation: 6 pm or less - Temperature: 20C f 1 oc (50 I 2)% 86 kPa to 106 kPa - Relat
4、ive humidity: - Barometric pressure: 2.3 Specimens shall be stored under the test conditions specified in 2.2 for 24 hours prior to the test. 3 Cassette types There are two cassette types which are identified by outside dimensions shown below: 5 Leader tape and trailer tape The leader tape and trail
5、er tape shall have the follow- ing characteristics: 5.1 Light transmissivity: 50% or more (measured over the range of wavelengths 700 nm to 900 nm) 5.2 Length: - Large cassette: - Small casseite: 170 mm I15 mm 140 mm f 10 mm - Large cassette (L): - Small cassette (S): 106 x 188 x 25 mm 87 x 130 x 25
6、 mm Length of the leader and trailer tape is defined be- tween the end of the leader or trailer tape to a point 4 Videotape The video tape shall have the following charac- teristics: where this tape is attached by a splicing tape to the metal particle tape. 5.3 Tape thickness: 13 pm to 36 pm 5.4 Wid
7、th: 12.65 mm f 0.02 mm 5.5 Splicing tape length: 13 mm to 20 mm 4.1 Type of video tape: Metal particle 4.2 Base material: Pol yet h y le ne terephthalate or its equivalent 5.6 Splicing tape thickness: 25 pm or less , CAUTION NOTICE: This Standard may be revised or withdrawn et any time. The procedur
8、es of the Standard Developer require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of publication. Purchasers of standards may receive current information on all standards by calling or writing the Standard Developer. Printed in USA. Copyr
9、ight0 199byTHECOCIETYOF L American National Standard MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Haitsdale Ave., White Plains, NY 10807 (914) 761-1100 Approved December 2, 1996 STD.SMPTE 250M-ENGL 197b 8357401 0002599 2TO ANSVSMPTE 25M-1996 5.7 Splicing strength to reel hub: 20 N or more 5.8 Spli
10、cing strength to video tape: 20 N or more 5.9 Breaking strength of leader tape: 30 N ormore 5.10 offset yield strength of leader tape: 18 N or more 6 Video tape length and record/play- back time Tape length and recordplayback time specifications shall be as given in tables 1 and 2. 7 Video cassette
11、The video cassette shall be specified by the following descriptions: 7.1 Cassette dimensions Large cassettes shall conform to figures 1 to 8. Small cassettes shall conform to figures 9 to 20. Table 1 - Definition of play/record time for large cassette Recordlplay Tape Time (min) Length (m) 95 389 +i
12、 65 267 +i 35 145 +i 23 96 +i 12 51 +i Table 2 - Definition of playhecord time for small cassette Recordlplay Tape Time (min) Length (m) 23 12 7.2 Cassette datum system 7.2.1 Datum holes Datum holes shall be holes serving as a reference when loading a cassette in the video tape recorder, and shall a
13、lso be the datum reference of the cassette dimensions (see figures 2 to 4 and 1 O to 12). 7.2.2 Datum plane 2 Datum plane 2 shall be a plane containing three datum places, A, B, and C, on the cassette bottom (see figures 4 and 12). 7.2.3 Datum plane X 7.2.3.1 Large cassette This plane shall be ortho
14、gonal to datum plane 2 containing the centerlines of datum holes A and B (see figures 2 to 4). 7.2.3.2 Small cassette This plane shall be parallel to the long side face of the cassette and shall be orthogonal to datum plane 2, containing the centerline of datum hole A (see figures 10 to 12). 7.2.4 D
15、atum plane Y Datum plane Y shall be a plane orthogonal to both datum planes Z and X, containing the centerline of datum hole A (see figures 2 to 4 and 1 O to 12). 7.3 Window and label pasting face Large cassettes shall conform to figure 1 and small cassettes to figure 9. 7.4 Identification holes Mul
16、tiple holes shall be provided for identifying the conditions of the cassette (see figures 2 and 10). Each hole may be set in a closed state or an opened state: - Closed state: The hole depth shall be O mm to 0.25 mm and shall withstand a force of 0.5 N. Page 2 of 21 pages STD-SMPTE 250M-ENGL L79b 83
17、57q03 0002b00 892 - Opened state: The hole diameter shall be 3 rnm + 0.3 mm - 0.1 mm. The hole depth shall be 5 mm or more. 7.4.1 Record lock-out identification hole Large cassettes shall be as specified in figure 2 and small cassettes as in figure 10. The record lock-out identification hole shall b
18、e cou- pled to the record lock-out mechanism shown in fig- ures 1 and 9, and may be changed between the closed state and the opened state. Each state shall be de- fined as follows: - Identification hole closed: - Identification hole opened: Ready to record Record lock out 7.4.2 Tape type identificat
19、ion hole Large cassettes shall be as specified in figure 2 and small cassettes as in figure 1 O. The closed or opened state of the identification hole shall be defined as follows: - Identification hole closed : Metal particle tape (coercivity class 1500) - Identification hole opened: Reserved 7.4.3
20、Tape thickness identification hole Large cassettes shall be as specified in figure 2 and small cassettes as in figure 10. The closed or opened state of the identification hole shall be defined as follows: - Identification hole closed: Tape total thickness is 13.5 pm : , .?/ , i- 32 - I 69-02 NOTE 11
21、 03+0,:,? -N max ROS NOTES 1 Datum hole A. 2 Hole for the sensor lamp. 3 Holes for the sensor optical path. 4 Reel brake unlocking hole. 5 Datum hole B. 6 Guide groove A to prevent misinsertion. 7 Guide groove B to prevent misinsertion. 8 Guide groove C to prevent misinsertion. 9 Record lock-out ide
22、ntification hole. 1 O Tape type identification hole. 11 Tape thickness identification hole. 12 Extra identification holes (five holes). 13 Grip for automatic loading machine. Figure 2 - Bottom view of large cassette 1.5 - Page 5 of 21 pages STD*SMPTE 250M-ENGL 379b 8357403 0002b03 551 ANSVSMPTE 2501
23、111-1996 max. 16.5 NOTE3 6W 4 15 Datum plane X NOTES Datum plane Y t Datum plane 2 =!?I- - Supply side sensor optical path angle. Take-up sensor optical path angle. Pushing position of the lid uniocking device. Position of the brake unlocking pin of the recorder. The space of this dimension shall be
24、 maintained throughout the entire circumference of the inner wall. Maximum permissible height when the lid is opened. The lid minimum opening dimension. This dimension shall be applied over the cassette front tape threading range (see figure 7 for tape threading path). Figure 3 - Inner structure of
25、large cassette Page 6 of 21 pages Datum place D / STD-SMPTE 250M-ENGL 199b 8357401 0002bO4 498 ANSVSMPTE 250M-1996 NOTE 2 i 98.5 i 0.2 - - 37.5 4.0.2 I v) 20 min. 7 +. 4 !. NOTE 1 NOTES 1 The diameter of the datum hole in section A-A shall be 4.05 rnrn + 0.05 rnm - 0.00 mm and 7 rnm in depth. 2 The
26、flatness of the four datum places shall be 0.2 rnm or less. The datum places are used as the supporting surfaces of the cassette. Figure 4 - Datum places and support surfaces of large cassette Page 7 of 21 pages STD-SUPTE 250U-ENGL 399b 8357403 0002b05 324 ANSVSMPTE 25OM-1996 L (a) Condition off the
27、 machine I (b) Condition loaded on the machine NOTES 1 Centerline of tape. 2 Height of reel stand above cassette datum plane Z. The cassette tape reel shall be smoothly operated at a height of 2.0 mrn f 0.2 mm. 3 Reel springs. 4 E value (a margin between reel flange outside diameter and maximum woun
28、d tape diameter). 5 Reel stoppers to limit the play of the reel. Figure 5 - Relationship between reels and reel stands for large cassette Page 8 of 21 pages STD-SMPTE 250M-ENGL L77b m 8357403 0002bOb 2b0 m ANSVSMPTE 250M-1996 Figure 6 - Reei dimensions of large cassette I Figure 7 - Tape path in lar
29、ge cassette Page 9 of 21 pages ANCVCMPTE 25OM-1996 2+o.1 c 86.7I0.5 - 0.2 25.80.5 1 10.5 I. I - 19I0.5 I - -0.2 - 2+o.1 86.7I0.5 1- Datum plane X min. 0.4 Section A-A Section B-B $1 NOTES 1 Either one of two screw positions may be used. 2 Either one of two screw positions may be used. I- l Datum pla
30、ne Y I Datum plane X Section C-C Figure 8 - Screw positions and lid structure of large cassette Page 10 of 21 pages STD*SMPTE 250M-ENGL L77b 8357401 0002b08 033 7.5 i 0.3 - ll Arrow C I . 79.5 10.15 m 1 187) I I NOTE 7 - Y) O w Z Y) O h Y) - NOTES ANSUSMPTE 250M-1996 min. 3 - l Ir I iJ Datum plane i
31、! - NOTE 1 2510.2 rt- 12-1 o. / / NOTE 3 Section A-A Section B-B I 1 Top label pasting face. The label shall not protrude beyond the cassette height. 2 Guide groove to prevent misinsertion. 3 Operation of record lock-out hole. When the record lock-out hole is open, recording should be impossible. Wh
32、en the hole is closed, recording should be possible. The record lock-out mechanism shall be coupled with the identification hole shown in figure 10 (note 6). 4 Window. This window shall not protrude beyond the cassette height. 5 Side label pasting face. The label shall not protrude beyond the casset
33、te side. 6 Lid unlocking clutch. 7 Cassette front positioning face. 8 These tolerances include a slight play of the lid. Figure 9 - Top and side views of small cassette Page 11 of 21 pages ANSVSMPTE 25OM-1996 Datum plane Z NOTES 1 Datum hole. 2 Hole for sensor lamp. 3 Holes for sensor optical path.
34、4 Reel brake unlocking hole. 5 Guide groove to prevent misinsettion. 6 Record lock-out identification hole. 7 Tape type identification hole. 8 Tape thickness identification hole. 9 Extra identification holes (two holes). 10 Grip for automatic loading machine. Figure 10 - Bottom view of small cassett
35、e Page 12 of 21 pages STD-SUPTE 25UM-ENGL 377b 8357403 0002bLO 771 ANSIISMPTE 250M-1996 Datum plane X L ,+O.l “el: i 1 1 NOTES 1 Supply side sensor optical path angle. 2 Take-up side sensor optical path angle. 3 Position of the brake unlocking pin of the recorder. 4 Finger hole. 5 This dimension sha
36、ll be maintained throughout the entire circumference of the inner wall. Figure 11 - Inner structure of small cassette Datum plane Y - Datum plane i 7 Page 13 of 21 pages STD-SMPTE 250M-ENGL L99b 8357LiOL 0002bLL b28 ANSVSMPTE 250M-lsW Section cc -,Datum plane x Arrow 6 NOTES 1 The diameter of the da
37、tum hole in section A-A shall be 4.05 mm + 0.05 mm - 0.00 mm and 7 mm in depth. 2 The flatness of the four datum places shall be 0.2 mm or less. 3 The flatness of the four supporting surfaces shall be 0.2 mrn or less. The supporting surfaces are used as the cassette supporting suriaces for cassette
38、loading. Figure 12 - Datum places and supporting surfaces of small cassette Page 14 of 21 pages ANSUSMPTE 250M-1996 (a) Condition off the machine (b) Condition loaded on the machine NOTE 4 A s o NOTES 1 Centeriine of tape. 2 Height of supply reel stand above cassette datum plane 2. The cassette shal
39、l operate smoothly at a height of 2.0 mm rf: 0.2 mm. 3 Height of take-up reel stand above cassette datum plane Z. The cassette shall operate smoothly at a height of 1 .O mm f 0.2 mm. 4 Reel springs. 5 E value (a margin between reel flange outside diameter and maximum wound tape diameter). 6 Reel sto
40、ppers to limit the play of the reel. Figure 13 - Relationship between reels and reel stands of small cassette Page 15 of 21 pages STD-SMPTE 250M-ENGL 199b 8357401 0002b13 4TO W ANCVSMPTE 250M-1996 - 1 t I 926 f 0.15 - min. 21.8 +3O 0.3 + 0.3 * 3.1 o 0.4 + Figure 14 - Supply reel dimensions of small
41、cassette Page 16 of 21 pages STD-SMPTE 25UM-ENGL 177b 8357403 0002b34 337 T? O0 +I v in 2 E E .- t Lo z c E .- ANSIICMPTE 250M-1996 O Q20-0.1$ - Figure 15 - Take-up reel dimensions of small cassette Page 17 of 21 pages STD*SMPTE 250M-ENGL L77b 8357LiOL 0002bL5 273 ANSVCMPTE 2501111-1996 Take UP reel
42、 Magnetic coaling side SUDPV reel Figure 16 - Tape path in small cassette NOTE 1 7 Pivot - Pivot A T- 1L-j Datum 14.1 i.2 Plane Z NOTES Recess to prevent misinsertion. Tape upper edge position. Tape lower edge position. Margin for tape position changes shall be 1.5 mm or more. Maximum permissible he
43、ight when lid is opened. Figure 17 - Lid structure of small cassette 1 Datum plane 2 Page 18 of 21 pages STD-SMPTE 250M-ENGL L77b 8357401 0002bLb LOT ANSUSMPTE 250M-1996 Datum dane Y min. 47 min. 49 ,aA Datum plane 2 F w Section A-A min. 20 -i Section B-B Datum plane X 7 Figure 18 - Minimum clearanc
44、e for recorder and player loading mechanism Page 19 of 21 pages ANSVSMPTE 2501111-1996 1 I I Section A-A I Datum plane X , NOTE 1 - Lid unlocking position Figure 19 - Unlocking structure of lid Page 20 oi 21 pages STD-SMPTE 250M-ENGL L77b H 8357qOL 0002638 T82 H - 60.5 10.5 L Datum plane Y Y 55 10.5
45、 -4 NOTE 1 7 ANSUSMPTE 250M-1996 Datum plane X NOTE 1 -The screw position also serves as the positioning point for mounting a small cassette in video tape recorders. The diameter of the spot facing for the screw head of this portion is 5.3 mm to 5.7 mm, and the depth of the seat to the screw head is 3 mm or more. Figure 20 - Screw positions of small cassette Page 21 of 21 pages
