ANSI SMPTE ST 32M-1998 Video Recording - 1 2-in Type H - Cassette Tape and Records.pdf

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1、SMPTE STANDARD for Video Recording - V2-h Type H - Cassette, Tape and Records SMPTE 32M-1998 Revision of ANSIISMPTE 32M-1993 Table of contents 1 Scope 2 Normative references 3 Basic type H parameters and characteristics 4 LP and EP modes 5 FM audio recording characteristics 6 Compact video tape and

2、cassette 7 High-performance type H cassette, records and system Annex A High-quality mode technology Annex B Compact video cassette adaptor 1 Scope This standard specifies the characteristics and parameters for type H, helical-scan, 1/2-in video tape recorders operating with video signals as defined

3、 by ITU-R BT.470 and ANSVSMPTE 170M, and having a typical scanning structure of 525 lines, 59.94 fields per second, and 2:l interlace. This standard also specifies the double record time mode (long play, LP) and the triple record time mode (extended play, EP), and optional frequency modula- tion (FM

4、) audio recording. This standard further specifies the dimensions of the video tape and compact video cassette for use in a type H, helical-scan, 1/2-in video tape recording cassette system with the aid of a cassette adaptor. Finally, this standard specifies the characteristics and parameters for hi

5、gh-performance type H, helical- Page 1 of 44 pages scan, 1/2-in video tape recorders operating with video signals as defined by ITU-R BT.470 and ANSVSMPTE 170M, and having a typical scanning structure of 525 lines, 59.94 fields per second, and 2:l interlace. 2 Normative references The following stan

6、dards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility

7、 of applying the most recent edition of the standards indicated below. ANSVSMPTE 170M-1994, Television - Composite Analog Video Signal - NTSC for Studio Applications ITU-R BT.470-4, Television Systems 3.1 General specifications 3.1.1 Measurement conditions The dimensions shall be measured with no tr

8、ansverse or longitudinal tension applied to the tape. 3.1.2 Measurement environment The temperature shall be 20C I 1 OC, with a relative humidity of (50 I2)%. The users attention is called to the possibility that compliance with this standard may require use of an invention covered by patent rights.

9、 By publication of this standard, no position is taken with respect to 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 cond

10、itions to applicants desir- ing to obtain such a license. Details may be 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 O 1998 by THE SOCIETY OF MOTION PICTU

11、RE AND TELEVISION ENGINEERS 595 W. Hartsdale Ave., While Plains, NY 10607 (914) 761-1100 Approved September 23,1998 STD SMPTE CMPTE 32M-1998 32M-ENGL 3.1.3 Tape speed The tape speed shall be 33.35 mm/s f 0.5%. 3.1.4 Video writing speed The nominal video writing speed shall be 5.80 ds. 3.1.5 Video he

12、ad drum diameter The video head drum diameter shall be 62.00 mm f 0.01 mm. 3.2 Video tape and video cassette 3.2.1 Tape characteristics 3.2.1.1 Length and thickness dimensions The length and thickness dimensions of the video tape shall be as given in table 1. 3.2.1.2 Tape width The average tape widt

13、h shall be 12.65 mm fO.01 mm. Width fluctuation shall not exceed 6 pm. The average tape width is the average of measured values of the width of the video tape, made at many points along a length of the video tape. 3.2.1.3 Tape type The type of video tape to be used shall be high resolution videotape

14、 (for example, cobalt iron-oxide tape). 3.2.1.4 Coercivity The coercivity shall be approximately 50 x 1 O3 Alm. 1998 8357401 00033bL 3TB 3.2.2 Leader and trailer tape 3.2.2.1 Length The length of the leader and trailer tapeshall be as follows: - T-160, T-120 and T-90 - T-60 and T-30 170 mm f 20 mm;

15、150 mm I20 mm. The length of the leader and trailer tape is defined to be the distance between the point where they attach to the reel hub and the point where they attach (splice) to the magnetic tape. 3.2.2.2 Thickness and width The thickness of the leader and trailer tape shall be 40 pm +5 pm -25

16、pm. The width shall be 12.65 mm f 0.03 mm. 3.2.2.3 Material The material shall be polyester film or its equivalent with a light transmission greater than 50% (measured over the range of wavelengths 800 nm to 950 nm). 3.2.2.4 Attachment The attachment of the leader and the trailer to the video tape a

17、nd to the reel hubs shall be capable of withstanding a pulling force of at least 30 N. The leader-to-video-tape and trailer-to-video-tape splicing gaps shall each be less than 0.07 mm. 3.2.3 Video cassette Dimensions for the video cassette are shown in fig- ures 1 to 5. The path of the video tape wi

18、thin the cassette is shown in figure 6. Table 1 - Video tape dimensions Tape length Play i ng ti me Reei hub diameter Tape thickness Name m min mm Pm T-160 327 o 160 26 15.6 f 0.5 +3 +3 +1 T-120 246 o 120 26 19.0 - * T-90 T-60 +3 185 o +3 125 o 90 60 26 62 +i 19.0 - +I 19.0 - +1 T-30 64 0 30 62 (or

19、70) 19.0 -2 Page 2 of 44 pages SMPTE 32M-1998 NOTE 8 - no3 NOTE O - SECTION A-A SECTION 8-8 SECTION C-C SECTION 0-D NOTES 1 Top label area. 2 Guide groove A to prevent improper insertion. 3 Guide groove B to prevent improper insertion. 4 Break-out lug to prevent accidental erasure. 5 Window for take

20、-up reel. 6 Window for supply reel. 7 Side label area. 8 Unlocking pin for the front cover. The unlocking force is 9 Groove for positioning of cassette. less than 0.15 N. 1 O Allowances include slight play of the front cover. 11 Recess to prevent improper insertion. Figure 1 - Top and side views of

21、video cassette Page 3 of 44 pages STDmSMPTE 32M-ENGL 1998 8357403 00033b3 170 SMPTE 32M-1998 74k0.15 LESS THAN R2 86t0.25 i I -1 4 SECTION A-A LE88 O oc C F NOTES 1 Reference hole. 2 Hole for the sensor lamp. 3 Hole for the sensor light pass. 4 Unlocking hole for the reel brake. The unlocking force

22、is 5 Datum plane. The flatness of the fourdatum planes shall 6 Guide groove A to prevent improper insertion. 7 Guide groove B to prevent improper insertion. 8 Auxiliary hole position. be less than 0.2 mm. less than 0.69 N. Figure 2 - Bottom view of video cassette Page 4 of 44 pages NOTES ES N CMPTE

23、32M-1998 .- m I+= 4 The cover opens more than 27 mm. The opening force 1 Sensor light angle of supply side. 2 Sensor light angle of take-up side. 3 Pushing position of the cover unlocking device of the is less than 1 N. 5 Position of the brake unlocking pin of the recorder. 6 Position of the lever i

24、n the recorder for opening the recorder. cassette cover. Figure 3 - Inner structure and reels Page 5 of 44 pages STD-SUPTE 32M-ENGL 1778 H 8357q01 00033b5 T43 SMPTE 32M-1998 NOTE 3 P -i +I 01 N NOTES 1 Center of tape. 2 Height of the reel base from the cassette datum plane. The cassette shall operat

25、e smoothly at a height of 2.0 mm 3 Reel spring. + 0.8 mm - 0.5 mm. Figure 4 - Relationship between reels and spindles .I I Figure 5 - Reel spindle CO Figure 6 - Tape winding Page 6 of 44 pages STD-SMPTE 32M-ENGL L798 8357401 00033bb 78T CMPTE 32M-1998 VIDEO 1 TRACK VIDEO 2 TRACK IUDIOGUARD CONTROL H

26、EAD +x4 Lt REFERENCE EDGE SWITCH I NO Figure 7 - Track configuration from magnetic coating side Page 7 o 44 pages STD-SMPTE 32M-ENGL 1998 I8357LlflL 00033b7 Alb SMPTE 32M-1998 Table 2 - Track configuration (refer to figure 7) Dimensions Description SP mode mm A B C D E F H L P R T W X a 0 eo Tape wi

27、dth Video recording area width Control track width Audio 2 track width (stereophonic) Audio 1 track width (stereophonic) Audio track reference line Audio-to-audio track guard band Video track center from reference edge of tape Video track pitch Audio track width (monophonic) Video track width Video

28、recording effective area Position of audio and control track head Video head azimuth angle Video track angle Video track angle (tape stationary) Track shift error (from logical value) Track bend (peak-to-peak value) 12.65 I 0.01 10.6 0.75 k O. 1 O 0.35 + 0.05 0.35 10.05 11.65 I 0.05 0.3 6.2 0.058 1.

29、0 I 0.1 0.058 10.07 79.244 +6“ and -6“ 5“ 58 9.9“ 5“ 56 7.4“ 0.01 4 0.01 4 JOTES Values are nominal where there are no tolerances specified. ! Dimension 80 represents the video track angle without linear motion of the video tape, such as might result from repetitive reading of a single track (one fi

30、eld) of the video record on the tape. 3.3 Video tape records; SP mode track configura- tion and dimensions L Switching position The track configuration and the transverse and longi- tudinal dimensions in the SP mode shall be as speci- fied in figure 7 and table 2. 3.4 Audio and control track head po

31、sition The distance X on the tape pattern, from the end of the 180“ scan of a video head to the audio and control track head position, shall be 79.244 mm, as shown in figure 7. 3.5 Audio record displacement Program audio or other information which is time coincident with video information recorded a

32、t a point So of the video 2 track shall be recorded on either audio track at a distance X downstream from that point (So). (See figure 7.) So is the center of the video track at the switching position of the video heads. Minimum overlap Figure 8 - Switching position and overlap of two video heads Pa

33、ge 8 of 44 pages STD-SMPTE 32M-ENGL 3778 8357403 00033b8 752 W SMPTE 32M-1998 3.6 Video head switching The switching position between the two heads during playback shall lie between 5 and 8 horizontal lines ahead of the leading edge of the vertical sync signal, as shown in figure 8. 3.9.1.1.2 Preemp

34、hasis The luminance video signal shall be preemphasized prior to frequency modulation. The preemphasis net- work characteristic shall be as shown in figure 9. 3.9.1.1.3 Clipping 3.7 Tape tension The tape tension for the record and playback modes, measured with a spring scale for a full supply reel,

35、shall be normally from 0.30 N to 0.45 N at the entrance of the drum when the tape is pulled at the specified speed. 3.8 Relationship of video track and video field signal Type H recording devices, whose applications require that each video signal field and video tape track be distinguished, shall re

36、cord video field 1 on video tape track 1, and video field 2 on video tape track 2. 3.9 Video recording The video recording system shall provide separate signal paths for the luminance and chrominance sig- nals. The luminance signal shall be frequency modu- lated on a high-frequency r carrier signal

37、prior to recording. The chrominance signal shall be down- converted to a low frequency prior to recording. After this separate processing, the signals shall be com- bined and recorded together on a single video track. The preemphasized luminance video signal shall be clipped prior to frequency modul

38、ation. The clipping levels are as shown below. The level from sync tip to peak white is defined to be 100%. - White clipping level measured from tip of sync: 160% nominal, 155% minimum, 200% maximum; - Dark clipping level measured from tip of sync: - 40% nominal, -50% minimum, -30% maximum. 3.9.1.1.

39、4 Modulation characteristics The preemphasized and clipped luminance video signal shall be frequency modulated (FM) by a linear frequency modulator, having constant deviation with respect to the amplitude of the modulating frequencies, on an r carrier corresponding to the reference luminance video l

40、evels below: - Reference white level (100 IRE units) 4.4 MHz k 0.1 MHz; - Reference sync level (40 IRE units) 3.4 MHz i 0.1 MHz; - Frequency deviation, ref white to ref sync (140 IRE units) 1 .O MHz IO.1 MHz. 3.9.1 Luminance channel 3.9.1.1.5 High-pass filter 3.9.1.1 Signal processing A luminance si

41、gnal processing system, as specified in this standard, shall contain the following elements in the order of the signal flow: 3.9.1.1.1 Separation filter The luminance signal component of the composite video signal shall be separated from the chrominance component by a filter that attenuates the lumi

42、nance signal by no less than 40 dB at the chrominance subcarrier frequency. The FM r carrier, frequency modulated by the lumi- nance video signal, shall be processed by a high-pass filter prior to recording. The high-pass filter network characteristic shall be as shown in figure 1 O. 3.9.1.1.6 Recor

43、ding level The record current shall be set to the optimum value over the entire bandwidth of the FM carrier. Optimum record current shall be that which returns the maxi- mum output signal level during playback. Page 9 of 44 pages SMPTE 32M-1998 STD-SMPTE 3SM-ENGL 1798 68357403 00033b9 b99 I o U W v)

44、 z O v) w m W a 0.04 0.05 0.07 O1 0.2 0.3 0.4 0.5 0.7 1 2 3 45 FREQUENCY (MHz) C IN T= CxRb=1.3ps+ 0.05 X = Rb/Ra = 4 f 0.3 T = 1.35 FS x = 4.3 T = 1.25 LC x = 3.7 . . . . (1) . . . . (2) Figure 9 - Preemphasis characteristic of luminance signal Page 10 of 44 pages STD SMPTE 32M-ENGL 0003370 300 SMP

45、TE 32M-1998 fc 1 3 FREQUENCY (MHz) A = Greater than 17 dB. B = Greater than 10 dB. f, = Converted chrominance carrier frequency (629.371 kHz). Figure 10 - FM high-pass filter 3.9.2 Chrominance channel 3.9.2.1 Signal processing A chrominance signal processing system, as speci- fied by this standard,

46、shall contain the following ele- ments in the order of signal flow: 3.9.2.1.1 Separation filter The chrominance signal component of the composite video signal shall be separated from the luminance component by a band-pass filter. Characteristics of the band-pass filter shall be as follows: - Center

47、frequency: 3.58 MHz; - Response: -3 dB at 4.08 MHz; -3 dB at 3.08 MHz. 3.9.2.1.2 Recording level The chrominance signal is recorded directly on the video tape as an amplitude modulated (AM) t carrier. Record level shall be such that the amplitude of the played back chrominance signal is 7 dB to 10 d

48、B below the saturation level of the recording chromi- nance signal. 3.9.2.1.3 Color burst amplitude doubler The amplitude of the color burst part of the chromi- nance signal shall be increased by 6.0 dB 10.5 dB prior to recording. 3.9.2.1.4 Chrominance frequency conversion The chrominance signal sha

49、ll be (down) converted such that the new carrier frequency to be recorded equals the horizontal scanning rate, multiplied by 40 (629.371 kHz). (See figure 11 .) 3.9.2.1.5 Chrominance carrier phase rotation The chrominance carrier shall be shifted in phase at every horizontal sync pulse as follows: - video track 1: phase of the previous horizontal line period; - video track 2: Retard -90“ from the carrier phase of the previous horizontal line period. Advance +90 from the carrier Shift of phase shall be completed before color burst occurs in each horizon