1、 STD-SMPTE 227fl-ENGL L77b m 8357403 0002573 T94 m - SMPTE STANDARD CAUTION NOTICE This Standard may be revised or withdrawn at any time The procedures of the Standard Developer require that action be taken to reaffirm, revise, or withdraw this standard no later than five years from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 publ
2、ication Purchasers of standards may receive current information on all standards by calling or wnting the Standard Developer Pnnted in USA for Television Analog Recording - 1/24 Type L - Records ANWSMPTE 229M-1996 Revision of ANSI/SMPTE 229M-1991 1 Scope This standard specifies the dimensions and lo
3、cation of the video, audio, time code, and tracking-control records, as recorded by 1/2-in type L helical-scan video tape recorders operating with video signals having a typical scanning structure of 525 lines, 59.94 fields per second, and 2:l interlace. Use is made of the video cassette and tape sp
4、ecified in ANSI/SMPTE 35M for type G format or ANSVSMPTE 238M for type L format. Page 1 of 5 pages - Barometric pressure - Tape tension 86 kPa to 106 kPa 0.46 N k 0.05 N 3.3 Conditioning of the tape stock before record- ing and testing shall be as follows: .- Environmental: specified in 3.2 Stabiliz
5、ed to the conditions - Tape tension: Wound on a reel at a tension of 0.56 N i 0.20 N 2 Normative references - Conditioning time: 24 hours The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions
6、 indicated were valid. All standards are subject to revision, and parties to agreements based On this standard are encouraged to investigate the possibility of applying the most recent editions of the standards 3.4 The reference edge Of the tape for dimen- sions specified in this standard be the low
7、er edge as in figure l. The magnetic with the direction of tape travel as Shown in figures 1 and 2, is on the side facing the Observer- indicated below. 4 Tapespeed ANSVSMPTE 35M-1991, Television Analog Record- ing - 1/2-in Type G - Cassette and Tape The tape speed shall be 11 8.582 mm/s, basic, and
8、 shall result in dimension “O” as shown. Copyright O 1996 by THE SOCIEN OF American National Standard MOTION PICTURE AND TELEVISION ENGINEERS 595 W. Harisdale Ave., White Plains, NY 10607 (914) 761-1100 Approved October 10,1996 STD-SMPTE 229M-ENGL L99b 8357qOL 000257Li 920 ANSVSMPTE 229M-1996 t AUDI
9、O 1 +I DIRECTION OF TAPE TRAVEL TIME CODE ttttt Y Figure 1 - Record locations and dimensions REFERENCE EDGE Figure 2 - Video record location (525/60) Page 2 of 5 pages STD-SMPTE 229M-ENGL 179b - 8357iOL 0002575 867 ANCVCMPTE 229M-1996 Table 1 - Record locations and dimensions Dimensions Micrometers
10、Minimum Nominal Maxi mum A B C D E F G H J K L M N O P Q R S T W Y Time code track lower edge Time code track upper edge Color track width Y-C track pitch Control track lower edge Control track upper edge Video track lower edge Video track upper edge Audio 1 track lower edge Audio 1 track upper edge
11、 Audio 2 track lower edge Audio 2 track upper edge Y track width Lead signal overlap Y-C track offset Video track pitch Video track length Control track record offset Audio and time code record offset Video area effective width Lower limit of W O 330 68 77.5 635 1035 880 10720 10805 11390 1 1790 124
12、05 83 161.0 36600 180681 1238 O O 400 470 73 78 80.5 83.5 700 765 1100 1165 950 1020 10720 10805 10850 10895 1 1450 11510 1 1850 11910 12450 12495 86 89 8.3H ref 4399 (= 10H) ref 161.4 161.8 11 5032 (262.5H) basic 36700 36800 18091 8 181155 9384 ref 1248 1258 Track angle (degrees) 4.6790 (basic) NOT
13、E - Ref indicates those measurements which are fixed by other parameters and are given for reference purposes only. 6 Video record curvature lhe edge of any video record contained within an area defined by dimension W shall lay within two parallel straight lines 0.010 mm apart (see annex A for prefe
14、rred measurement technique). 7 Relative positions of recorded signals 7.1 Video luminance, color difference, tracking control, audio, and time code signals, with infor- mation intended to be time coincident, shall be - - positioned as shown in figure 2. 7.2 Luminance and color-difference records for
15、 fields 2 and 4 are offset by one-half line with respect to fields 1 and 3 (see figure 2). 8 Gapazimuth 8.1 lhe azimuth of the audio, tracking control, and time code head gaps used to produce longi- tudinal track records shall be perpendicular to the direction of relative head-to-tape motion (see fi
16、gure 2). 8.2 The azimuth of the video head gaps for the luminance signal shall be -15.25 and for the color-difference signals +15.25“ to the perpen- dicular of the direction of head motion. Page 3 of 5 pages ANSVCYPTE 2291-1996 Annex A (informative) Measurement technique MEASUREMENT PATH /- I/ i/ -R
17、EFERENCE EDGE PERFEND I CULAR TO MEASUREMENT PATH WITHIN O 10 Y(!J MUST US SAME HEAD FOR EACH MEASUREMENT I .e. EVERY 2“ TRACK) CTM = CONTROL TRACK PULSES IUNTENSIONED TAPEI CORRECTION FACTORS ACTUAL TAPE SPEED, TENSION o I i; 0 F = TENSION 10.46 NI L1 I = YOUNGS MODULUS 18000 N/mmJ A = CROSS SECTIO
18、NAL AREA ITHICKNESS X WIDTH) C, = CONTROL TRACK FREOUENCY S9.94 Hzl L = CORRECTED DISTANCE V,- = CTM * C-/l(l - F/E * AI1 PITCHES) Page 4 of 5 pages STD-SMPTE 227M-ENGL L77b 8357LiOL 0002577 b3T ANSUSMPTE 229M-1996 MODEL V, = VELOCITY OF HEAD wrt BANO V, = ACTUAL VELOCITY OP TAPE V, = VELOCITY of HE
19、AD wrt TAPE D = EFFECTIVE SCANNER DIAMETER N = SCANNER SPEED (FI THETA = TRACK ANGLE BETA = SCANNER HELIX ANGLE V, = PI*D*N T, : TIME BETWEEN HEAD PASSES 1 = N * HPPR HPPR = HEAD PASSES per REVOLUTION -VT/B*TI - FROM 0 PI * D * N * SINfBETAI TAN (THETA) = PI * D * N * COSIBETAJ - VTfiAmAL FROM Y,Cf?
20、T,CXL TAN THETA) = “TAPE- * THEREFORE: PI D * N * SINIEETAI YlMEcwrrcAL = * TAPE ACNAL * Pi * D * N * COS(BETA) - V,- TRACK LOCATION ERROR = Y I r - Y I r J-, Annex 6 (informative) Bibliography ANSIISMPTE 230M-1996, Television Analog Recording - 1/2-in Type L - Electrical Parameters, Control Code and Tracking Control SMPTE RP 144-1 995, Basic System and Transport Geometry Parameters for 11241 Type L Format Page 5 of 5 pages -
