HllllIlllllll|||llllllllllllllll|l|lllllllllllllllllllllllllllllllllllllll USOO5499148A United States Patent 1191 [11] Patent Number: 5,499,148 Kubota et al. > [45] Date of Patent: Mar. 12, 1996 [54] DIGITAL VIDEO TAPE REPRODUCING 4,963,961 10/1990 Honjo .................................... .. 358/310 APPARATUS COMPATIBLE WITH TAPES 5,136,437 8/1992 Tabuchi et al. 360/341 X HAVING A TRACK WIDTH DIFFERENT 5,148,331 9/1992 Kasluda et a1. .................... .. 360/77.15 FWRIgg/IHA ROTARY MAGNETIC HEAD FOREIGN PATENT DOCUMENTS 0026320 4/1981 European Pat. Off. ........ .. G11B 5/02 [75] Inventors: Yukio Kubota; Keiji Kanota, both of European :3 ------ -- 611B 5/588 uropean . Kanagawa’ Japan 146387 11/1981 Japan .................................. .. 360/331 [73] Assignee: Sony Corporation, Tokyo, Japan 3-8173 1/1991 Japan ' Primary Examiner—Andrew L. Sniezek [21] APP]_ NO_; 966,540 igttrémgy, Aigem‘, or Firm-William S. Frommer; Alvin 1n er ran 22 F1 d: 0 t. 23 1992 [ 1 16 c ’ [57] ABSTRACT [ 30 ] F orelgn' A pp 1'‘ca t'Ion Pr’10“ 't y Data In a digital video tape recording and/0r reproducing appa Oct. 30, 1991 [JP] Japan .................................. .. 3-310156 rams including a pair of rotary magnetic heads having a 6 predetermined head width and gaps with mutually different [2;] {In """""""""""" azimuth angles which helically scan a magnetic tape as the [ 1 _' ' ' """"""" " ' ’ ’ ' tape is advanced'in order to reproduce digital video signals [58] F ‘e 1d 0 f S care h """"""""""""""" " 360/73 ' 06 ’ 73 ' 12 j that have been previously- az1muth-recorded- 1n- oblique- 360/7301’ 27’ 32’ NH’ 33‘1’ 10'2_10'3’ tracks on the tape, there is a tape transport that can transport 358/335’ 310 the tape either at a standard speed or at a non-standard speed. 56 R f Ct d If the tracks recorded on the video tape have a track width [ 1 e erences l 9 equal to the head width, then the tape is transported for Us PATENT DOCUMENTS reproduction at the standard speed, whereas, if the track width is different from the head width, the tape is transported 43077417 12/1981 Tokyama 360/ i at the non-standard speed. For example, if the track width is 2kg? et a1‘ I135 twice the head width, then the tape is transported at twice the ’ ’ o o ' ' ' ' ' ' ' ' ' ' ' " standard speed. On the other hand, in another embodiment, 4,710,811 12/1987 Kondo 358/135 , _ _ , Takimoto _____ I‘ X WhCH th? track wldth 1S of tha head the tape 18 4,791,497 12/1988 Nakano et a1. .. 360/48 X transpo?ed at a non-Standard Speed that IS One-half the 4,803,570 2/1989 Kashida et a1. .. 360/32 X standard speed. 4,811,130 3/1989 Takayama ................ .. 360/103 X 4,827,359 5/1989 Ookawa et a1. ..................... .. 360/103 8 Claims, 7 Drawing Sheets 40 /34 I3A 21A ATF SERVO 2,2 23/ I4 I35 2/8 “"ggg? —- T30 28 / / 33Y 54 25 26 g _" DISASSEM.BLOCK H ‘Nil-E22?!‘ . FRAM/ E BLéCK gm / 3! 7:2 330? Eco L" DlSASSEM.’ —“ DEC- E 29 z 36 '13- / g -‘ 3’ “A = 4 6822a = 2 33¢ - In a: 8 5°C _" @6005D10 _’'</ E_ E 39 5m _ ECC 45 /44 I.D. CONTROL DETECT US. Patent Mar. 12, 1996 Sheet40f7 I 5,499,148 _ 40 TB TA TB TA / / / k / US. Patent _ Mar. 12,1996 Sheet 5 of7 5,499,148 I I352 / 3/4 2 / FIG.8A FIG.8B TA! TA2 40 1780/ '7B'/ 782/ FIG.9 US. Patent Mar. 12, 1996 Sheet 6 0f 7 5,499,148 TBo TB, T32 TAo TA, TA2 TA 40 ‘ ~ ~ ~ ‘ "438 13A I38 FIG.11 5,499,148 1 2 DIGITAL VIDEO TAPE REPRODUCING postamble used for editing, control and the like, is approxi APPARATUS COMPATIBLE WITH TAPES mately 6.6’ Mbps. Thus the bit rate of all the data to be HAVING A TRACK WIDTH DIFFERENT recorded can be expressed as follows: FROM A ROTARY MAGNETIC HEAD WIDTH Dt = Dv + D11 + D0 = 205.8 + 12.8 + 6.6 = 225.2 Mbps BACKGROUND OF THE INVENTION In order to record this amount of information data, the 1. Field of the Invention known D1 format digital VTR employs a segment system This invention relates to digital video tape recorders, and having a track pattern made up of ten tracks for each ?eld in more particularly to a video tape recording and/or reproduc the NTSC system, or made up of twelve tracks for each ?eld ing apparatus, hereinafter a VTR, that may reproduce a in the PAL system. video signal from a magnetic tape using a magnetic head that In these digital VTRs, a recording tape having a width of is different in width from a magnetic head with which the 19 mm is used. There are two types of recording tapes which tape was recorded. respectively have thicknesses of 13 pm and 16 pm. To house 15 2. Description of the Prior Art these tapes, there are three types of cassettes, which are respectively known as large, medium and small sizes. The A D1 format component-type digital VTR and a D2 information data is recorded on such tapes in the D1 format format composite~type digital VTR have been developed for with a tape area for each bit of data of approximately 20.4 use by broadcasting stations in digitizing color video signals 11ml. When the recording density is increased, errors tend to and recording the digitized signals on a recording medium, 20 take place in the playback output data due to interference such as a magnetic tape. In the D1 format digital VTR, a between codes or non~linearity in the electromagnetic con luminance signal and ?rst and second color different signals version system of the head and tape. Heretofore, even if are A/D converted with sampling frequencies of 13.5 MHz error correction encoding is used, the above given value of and 6.75 MHz, respectively. Thereafter, the signals are the recording density has been the limit therefor. suitably processed and then recorded on a magnetic tape. 25 Taking the above described parameters into account, the Since the ratio of sampling frequencies of the signal com recording capacities of the cassettes having the various sizes ponents is 4:212, this system is usually referred to as the and the two tape thicknesses, when employed in the D1 4:2:2 system. ' format digital VTR, are as follows: On the other hand, in the D2 format video digital VTR, a composite video signal is sampled at a sampling rate that is Size/Tape Thickness 13 pm 16 pm four times higher than the frequency fsc of a color sub carrier signal and then is A/D converted. Thereafter, the small 13 minutes 11 minutes middle 42 minutes 34 minutes resultant signal is suitably processed and then recorded on a large 94 minutes 76 minutes magnetic tape. Since these known D1 and D2 format digital VTRs are 35 It will be noted that the recording capacities of these designed for professional use, for example in broadcasting cassettes are relatively short, the longest being just over 11/2 stations, attainment of high picture quality is given top hours. It has accordingly been desired to increase the record priority in the design and construction of such VTRs, and the ing capacity of tape cassettes used for digital video record weight and size of the apparatus is not overly important. ing by increasing the recording density. One approach to In these known digital VTRs, the digital color video 40 increasing the recording density is to reduce the track width signal, which results from each sample being A/D converted of the recording tracks in which the digital signals are into, for example, 8 bits, is recorded without being substan recorded. For example, if the track width were reduced by tially compressed. As an example, in the known D1 format one-half, e. g. from 10 pm to 5 pm, the recording density, and digital VTR which A/D converts each sample into 8 bits with hence the tape cassette recording capacity, can be doubled. the frequencies noted above, the data rate representing the 45 A way of reducing the track width is to use a recording head that has a narrower width. However, use of a narrower head color video signal is approximately 216 Mbps (megabits per and the resulting recording in narrower tracks, would cause second). When the data in the horizontal and vertical blank a lack of compatibility between VTRs using different sizes ing intervals are removed, the number of effective picture of magnetic heads. That is, tapes recorded on a conventional elements of the luminance signal per horizontal interval and 50 VTR using a wider head could not readily be reproduced by the number of effective picture elements of each color a VTR using a narrower head, and, conversely, recordings different signal per horizontal interval become 720 and 360, made using a narrower head could not readily be reproduced respectively. Since the number of effective scanning lines for by conventional, wider head, VTRs. each ?eld in the NTSC system (525/60) is 250, the data bit Further, if it were desired to standardize on a narrower rate Dv can be expressed as follows: head and track width, it may be that a VTR using the narrow 55 .ead would perform satisfactorily only if it remained sta tionary and in a good recording environment and would fail to perform satisfactorily if it were to be transported or used In the PAL system (625/50), since the number of effective in a location where vibration or other conditions tend to scanning lines for each ?eld is 300 and the number of ?elds interfere with recording.