CA1139432A - Magnetic recording and reproducing device - Google Patents
Magnetic recording and reproducing deviceInfo
- Publication number
- CA1139432A CA1139432A CA000324841A CA324841A CA1139432A CA 1139432 A CA1139432 A CA 1139432A CA 000324841 A CA000324841 A CA 000324841A CA 324841 A CA324841 A CA 324841A CA 1139432 A CA1139432 A CA 1139432A
- Authority
- CA
- Canada
- Prior art keywords
- tape
- recording
- signal
- tapes
- control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000005291 magnetic effect Effects 0.000 title claims abstract description 131
- 230000033001 locomotion Effects 0.000 claims description 17
- 238000012545 processing Methods 0.000 description 24
- 230000033458 reproduction Effects 0.000 description 17
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/76—Television signal recording
- H04N5/78—Television signal recording using magnetic recording
- H04N5/782—Television signal recording using magnetic recording on tape
- H04N5/783—Adaptations for reproducing at a rate different from the recording rate
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/005—Programmed access in sequence to indexed parts of tracks of operating tapes, by driving or guiding the tape
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/18—Driving; Starting; Stopping; Arrangements for control or regulation thereof
- G11B15/1808—Driving of both record carrier and head
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B15/00—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function
- G11B15/56—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function the record carrier having reserve loop, e.g. to minimise inertia during acceleration measuring or control in connection therewith
- G11B15/58—Driving, starting or stopping record carriers of filamentary or web form; Driving both such record carriers and heads; Guiding such record carriers or containers therefor; Control thereof; Control of operating function the record carrier having reserve loop, e.g. to minimise inertia during acceleration measuring or control in connection therewith with vacuum column
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
- G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
- G11B20/1816—Testing
- G11B20/182—Testing using test patterns
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
- G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
- G11B27/102—Programmed access in sequence to addressed parts of tracks of operating record carriers
- G11B27/107—Programmed access in sequence to addressed parts of tracks of operating record carriers of operating tapes
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
- G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
- G11B27/11—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information not detectable on the record carrier
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
- G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
- G11B27/19—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier
- G11B27/28—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording
- G11B27/30—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording on the same track as the main recording
- G11B27/3027—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording on the same track as the main recording used signal is digitally coded
- G11B27/3036—Time code signal
- G11B27/3054—Vertical Interval Time code [VITC]
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
- G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
- G11B27/19—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier
- G11B27/28—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording
- G11B27/32—Indexing; Addressing; Timing or synchronising; Measuring tape travel by using information detectable on the record carrier by using information signals recorded by the same method as the main recording on separate auxiliary tracks of the same or an auxiliary record carrier
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B27/00—Editing; Indexing; Addressing; Timing or synchronising; Monitoring; Measuring tape travel
- G11B27/10—Indexing; Addressing; Timing or synchronising; Measuring tape travel
- G11B27/34—Indicating arrangements
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B2220/00—Record carriers by type
- G11B2220/40—Combinations of multiple record carriers
- G11B2220/45—Hierarchical combination of record carriers, e.g. HDD for fast access, optical discs for long term storage or tapes for backup
- G11B2220/455—Hierarchical combination of record carriers, e.g. HDD for fast access, optical discs for long term storage or tapes for backup said record carriers being in one device and being used as primary and secondary/backup media, e.g. HDD-DVD combo device, or as source and target media, e.g. PC and portable player
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B2220/00—Record carriers by type
- G11B2220/60—Solid state media
- G11B2220/65—Solid state media wherein solid state memory is used for storing indexing information or metadata
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B2220/00—Record carriers by type
- G11B2220/90—Tape-like record carriers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B2220/00—Record carriers by type
- G11B2220/90—Tape-like record carriers
- G11B2220/91—Helical scan format, wherein tracks are slightly tilted with respect to tape direction, e.g. VHS, DAT, DVC, AIT or exabyte
Landscapes
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Multimedia (AREA)
- Indexing, Searching, Synchronizing, And The Amount Of Synchronization Travel Of Record Carriers (AREA)
- Television Signal Processing For Recording (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A magnetic recording and reproducing device comprising two video tape recording and reproducing parts, each of which has a tape running system which passes over a rotatable head drum and over a control head. Each tape is separately driven by a capstan which moves the tape in either longitudinal direc-tion over a control head in the tape path of each tape which provides means in connection with which means is provided for recording of VITC signal and a color bar on each tape. Control means is provided for transporting the tapes backward and forward in a selected time interval. The video tape recording and repro-ducing parts are alternately operated in every one field of the video signal. The tape control system employs an address signal inserted in a video signal so as to transport the tape rapidly and accurately to a predetermined position.
A magnetic recording and reproducing device comprising two video tape recording and reproducing parts, each of which has a tape running system which passes over a rotatable head drum and over a control head. Each tape is separately driven by a capstan which moves the tape in either longitudinal direc-tion over a control head in the tape path of each tape which provides means in connection with which means is provided for recording of VITC signal and a color bar on each tape. Control means is provided for transporting the tapes backward and forward in a selected time interval. The video tape recording and repro-ducing parts are alternately operated in every one field of the video signal. The tape control system employs an address signal inserted in a video signal so as to transport the tape rapidly and accurately to a predetermined position.
Description
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BACKGROU~ID OF THE INVENTION
Field of the Invention This invention relates to a magnetic recording and reproducing device in which one of a recording head and a recording medium is intermittently transported relatively to the other in forward and backward directions to form record tracks on which a video signal is recorded and from which the video signal is reproduced.
Description of the Prior Art A video disc recorder (VDR) is known which has two rotational magnetic discs, respectively, having magnetic surfaces on both sides and four magnetic heads. Each of the magnetic heads is moved intermittently in the radial direction to form concentric circular record tracks spaced by a predeter-mined length from each other for recording a video signal and reproducing it. Each of the magnetic heads effects operations of erasing of record track, recording, reproducing and inter-mittent movement in order. The four heads operate at different timings in relation to the four operations. As the recording and reproducing operation of this device is carried out through the magnetic head stopped during ~he operations, no guard band noise occurs on the reproduction picture in a slow reproduction mode, still reproduction mode and reverse reproduction mode in which the rotational speeds of the magnetic disc are different. In such VDR, a reproduced picture of high quality can be obtained.
In the VDR, however, there are problems that the magnetic disc is relatively expensive and the life time of its magnetic surface is relatively short. Further, it takes about four seconds to find out the top or initiation of recorded scene 113~43~
for reproduction, since a pulse motor is used for the inter-mittent transportation of the magnetic head. That is incon-venient for practical use of such VDR. Further, as operation for finding the top is carried out by watching the reproduced picture, it further takes a great deal of time before repro-duction starts.
On the other hand, a VTR is known in which the position of a rotary magnetic head is controlled transversely to the scanning direction thereof in accordance with reducing tape speed for obtaining a reproduction picture containing no guard band noise. However, since some phase error is produced in the reproduced signal by controlling the position of the head, it is difficult in such VTR to obtain a reproduced picture of high quality.
BRIEF SUMMARY AND OBJECTS OF THE I~VENTION
The present invention relates to a magneti.c recording and reproducing device employing two magnetic tapes which are intermittently transported in forward and backward directions to form record tracks by a head on which a video signal is recorded and from which the video signal is reproduced. Means is provided which includes an identification code recording and reproducing means to record and reproduce an identification code on or from a part of each record track with the video signal ` for identifying each of the record tracks. Memory means is included to memorize the identification code in accordance with the operation of a first operating means to be employed in the recording operation, the identification code being of a code at a point of time when the first operating means is operated. Distance detecting means is included to detect the .'~ I
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relative moving distance between the recording head and the recording medium in accordance with the operation of a second operating means which functions in the recording operation, on the basis of another identification code at a point of time when the second operating means is operated and the identification code memorized in the memory means. A returning movement control means to control the relative returning movement of the record medium to the position identified by the code at the time when the first operating means is operated, in accordance with the output of the distance detecting means, the returning move-ment being controlled so as to be carried out at a predetermined speed and then having intermittent movement when the relative distance reaches a predetermined value. Coincidence detecting means is also provided to detect the coincidence of a reproduced identification code obtained from the identification recording and reproducing means, then the identification code memorized in the memory means during the intermittent returning movement. A
returning movement stop signal is supplied to the returning movement control means. The device provides a tape control system using an address signal inserted in the video signal and control track signals so as to transport the tape faster . . , and accurately to the predetermined position.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a plan view of a VTR according to one embodiment of the present invention;
Figure 2 is a front view of a CTL head in Figure l;
Figure 3 is a block diagram of a drive control circuit for the VTR of Figure l;
Figure 4I and Figure 4II are partial plan views of a~
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magnetic tape on which record tracks are formed;
Figure 5 is a waveform of signals at the respective parts in Figure 3;
- Figure 6 is a view for explaining the scanning order of the record tracks;
Figures 7-A to 7-D and A' to D' are views for explaining the positional relationships between start tracks and stop tracks in the recording mode; and Figure 8 is a graph showing tape speed in the search mode for searching the start track.
DESCRIPTIO~ OF THE PRF.FERRED E~BODI~ ITS
Figure 1 is a plan view of a VTR according to a pre-ferred embodiment of this invention. This VTR consists of two VTR parts I and II. The one VTR part includes a first tape running system 1. The other VTR part includes a second tape running system 2. The first tape running system 1 is constituted by a supply reel (take-up reel) 3, a head drum assembly 4, a ~:, tape drive wheel 5 and a take-up reel (supply reel) 6. Similarly, the second tape running systen 2 is constituted by a supply reel (take-up reel) 7, a head drum assembly 8, a tape drive wheel 9 and a take-up reel (supply reel) 10. A pair of accumulators (vacuum columns) 13 and 14 are arranged between the first tape running system 1 and the second tape running system 2. Portions of magnetic tapes 11 and 12 threaded through the respective tape running systems 1 and 2 are temporarily stored in the accumulators 13 and 14 by vacuum action of the latter.
The four reels 3, 6, 7 and 10 are of the open-reel type.
The magnetic tapes 11 and 12 are wound on hubs of the reels 3, 6, 7 and 10, respectively. In the first tape running system 1, 1139~3Z
the magnetic tape 11 fed from the supply reel 3 is guided through a predetermined tape running path by guide pins 15, 16, 17, 18, 19 and 20. Similarly, in the second tape running system 2, the magnetic tape 12 is guided through another pre-determined tape running path by guide pins 21, 22, 23, 24, 25 and 26. The predetermined tape running paths of the first and second tape running systems 1 and 2 are symmetrical to each other in the VTR according to this embodiment.
In the first tape running system 1, control track 61 (CTL head) is arranged between the guide pins lS and 19 so as to contact with the magnetic tape 11. Similarly, in the second tape running system 2, another CTL head 62 is arranged between the guide pins 24 and 25 so as to contact with the magnetic tape 12. The CTL heads 61 and 62 are the ones which can record signals on, and reproduce signals from the magnetic tapes 11 and 12. Figure 2 is a front view of the CTL head 61 which has the same structure as the other CTL head 62. As shown in Figure 2, the CTL head 61 includes an upper magnetic head B
and a lower magnetic head F which are opposite to the upper and lower marginal portions of the magnetic tape 11 shown by the chain line in Figure 2. The magnetic heads B and F are located substantially at the same position with respect to the longi-tudinal direction (running direction) of the magnetic tape 11.
The rotary head drum assembly 4 includes a head drum 28 which is rotated in the clockwise direction. The other rotary head drum assembly 8 includes a head drum 29 which is rotated in the counter-clockwise direction. The rotational directions of the head drums 28 and 29 are in the running directions of the magnetic tapes 11 and 12. A magnetic head 31 is attached to a part of the peripheral portion of the head .:, ,:
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drum 2~. An erasing ma~netic head 32 is attached to the peripheral portion of the head drum 28 adjacent to the magnetic head 31. The magnetic erasing head 32 runs alon~ substantially the same scanning path as the magnetic head 31. Similarly, a magnetic head 33 and a magnetic erasing head 34 are attached to a part of the peripheral portion of the head drum 29, adjacent to each other. The magnetic heads 31 and 33 follow the magnetic erasing heads 32 and 3~ with respect to the rotational direction of the head drums 23 and 29, respectively. While the previously recorded signals are erased from the magnetic tape 10 or 11 by the magnetic erasing head 32 or 34, new signals are recorded on the magnetic tape 10 or 11 by the magnetic heads 31 and 33.
The tape drive wheel 9 for intermittently feeding the magnetic tape 12 is arranged near the head drum assembly 8, and it is in the form of cylindrical roller having a smaller diameter than the rotary head drum 29. Rubber is attached to the cir-cumferential surface of the drive wheel 9 to impart a consider-able frictional force to the magnetic tape 12. The tape drive wheel 9 is intermittently driven by a capstan motor 37 directly connected to the drive wheel 9.
The tape drive wheel 5 in the first tape running system 1 has the same structure as the tape drive wheel 9 in the second .. ..
tape running system 2. Similarly, it is intermittently driven by a capstan motor 36 directly connected to itself. The capstan motors 36 and 37 are, for example, DC motors. Code generators for detecting rotational angles of the motors 36 and . . ,~
i 37 are fixed to rotary shafts of the motors 36 and 37. The ~.
~ rotations of the motors 36 and 37 are controlled with the - detecting outputs of the code generators.
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Next, there will be described the accumulators 13 and 14 arranged between the first tape running system 1 and the second tape running system 2.
Through holes 38 and 39 are made in the accumulators 13 and 14 along the lengthwise directions of the accumulators 13 and 14, respectively. The through holes 3~ and 39 have rectangular cross-section the width of which is nearly equal to the width of the magnetic tapes 11 and 12. Air in the through holes 38 and 39 is sucked through pipes 40 and 41 by not-shown vacuum pumps, so that the slackened magnetic tapes 11 and 12 are guided into the through holes 38 and 39 in the form of letter U.
A pair of sensing elements 42 and 43 for detecting the magnetic tapes 11 and 12 are arranged at the side of the accumulator 13. A reel motor 44 to drive the reel 3 is rotated upon detecting output of the sensing element 42. And a reel motor 45 to drive the reel 7 is rotated upon detecting output of the sensing element 43. Similarly, another pair of sensing elements 46 and 47 for detecting the magnetic tapes 11 and 12 are arranged at the side of the other accumulator 14.
A reel motor 48 to drive the reel 6 is rotated upon detecting output of the sensing element 46. And a reel motor 49 to drive the reel 10 is rotated upon detecting output of the sensing element 47. Accordingly, portions of the magnetic tapes 11 and 12 of substantially predetermined length are always stored in .
the accumulators 13 and 14.
The magnetic tapes 11 and 12 are wrapped helically and entirely around the head drums 2~ and 29 in the form of letter a (alpha). Accordingly, record tracks are formed on the magnetic tapes 11 and 12 at a predetermined angle to the longi-.:.
~ tudinal direction of the magnetic tapes 11 and 12. In the ,'.
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recording operation and the reproducing operation, the magnetic heads scan the magnetic tapes 11 and 12 while they are stopped, respectively. Accordin~ly, the angles of the scanning paths of the magnetic heads in the recording operation and the reproducing operation are equal to each other regardless of tape running speed in the reproducing operation. No noise band occurs on the reproduced picture in any of the still re?roduction, the slow-motion reproduction and the reverse-motion reproduction.
Next, operations of the VTR according to this embodi-ment will be described with reference to Figure 3 to Figure 8.
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Figure 3 is a block diagram of a drive control circuit for the VTR part I shown in Figure 1. Another drive control circuit for the VTR part II shown in Figure 1 is equal to that for the VTR part I in construction. And the former operates in a similar manner to the latter except that the former's operation is different in timing from the latter's operation.
Figure 4-I and Figure 4-II are plan views of respective parts of the magnetic tapes 11 and 12 on which record tracks are formed, respectively. Figure 5 is wave forms of signals at the respective parts of the block diagram of Figure 3.
Figure 6 is a view for explaining the scanning order o~ the record tracks. Figures 7-A to 7-D and 7-A' to 7-D' are views for explaining the relationships between start tracks and stop tracks in the recording mode. And Figure 8 is a graph showing tape speed in the search mode for searching the start track.
In the recording operation and reproducing operation of the VTR according to this embodiment, the magnetic tapes 11 and 12 are transported forward and backward in a selected, predetermined time interval. In the VTR part I, when the mag-netic tape 11 is transported in the FW (forward) direction shown .
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by the arrow in Figure R-I, record tracks fl~ f3 fn shown by the solid lines are successively formed on the ma~netic tape 11. And when the magnetic tape 11 is transported in the BW
(backward) direction shown by the arrow BW in Figure 4-I, record tracks fn+2 ---- shown by the dotted lines are successively formed between the adjacent record-tracks shown by the solid lines on the magnetic tape 11. Also in the VTR
part II, record tracks are formed on the magnetic tape 12 in a similar manner. The VTR parts I and II alternately operate every one field of video signals. Video signals of odd fields are recorded on the magnetic tape 11 in the VTR part I, while video signals of even fields are recorded on the magnetic tape lZ in the VTR parts II.
In Figure 3, one of selecting buttons 51a, 51b, 51c and 51d in a time interval selection circuit 51 is selectively pushed to set the time interval of the recording operation.
For example, time intervals of 30 seconds, 60 seconds, 2 minutes and 5 minutes can be set by the selec~ing buttons 51a, 51b, 51c and 51d, respectively. When the selecting button 51a is pushed, the magnetic tapes 11 and 12 are transported forward and backward in the time interval of 30 seconds. In other words, the magnetic tapes 11 and 12 are transported one way, namely forward or backward in 15 seconds. New video signals are successively recorded on the magnetic tapes 11 and 12 in the time interval of 30 seconds .
;:~ Next, operations of the VTR of this embodiment will be ~ described in relation to the code recording mode, the recording :, mode and the reproducing mode.
(1), Code Recording Mode In the VTR according to this embodiment, a C~L signal, ~13~g3Z
a VITC (Vertical Interval Time Code) signal and a color bar video signal are recorded on the magnetic tapes 11 and 12 before video signals start to be recorded on the ma~net tapes 11 and 12. Such recording operation is hereinafter called as "code recording mode". Other address signals which can be inserted in the video signal can be used instead of VITC signal, such, for example, as the address signal shown in Tachi u.s. Patent 4,159,480, assigned to the same assignee as the present a?plication.
l~hen a code recording mode button 66 of a recording operation control part 64 is pushed in Figure 3, a code record-ing mode set signal is supplied through the button 66 to a pro-cessing circuit 53 to put the VTR into the code recording mode.
A siznal a having the vertical frequency of 60Hz is supplied from the processing circuit 53 to a drum servo circuit 54. A
drum motor 55 is rotated at the speed of 60Hz with the output of the drum servo circuit 54. Accordingly, the head drum ~8 for the VTR part I shown in Figure 1 is driven at the vertical ... .
frequency. The head drum ~9 for the VTR part II is rotated in the same manner.
; A video signal Vs is supplied to a vertical synchroniz-` ing signal separating circuit 68 through an input ter~inal 67 ofi; the drive control circuit of Figure 3. A vertical synchronizing signal VD separated through the separating circuit 67 is supplied to the processing circuit 53, so that the operation of the pro-cessing circuit 53 is synchronized with the vertical synchron-izing signal VD.
' A change-over switch 72 in Figure 3 is connected to REC
position in the code recording mode. The vertical synchronizing signal VD is supplied to a clock input terminal CP of a flip-flop -.
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73, so that a change-over signal A going high at every odd field as shown in Figure 5-A is formed at an output terminal ~ thereof.
The change-over signal A is supplied to a switching circuit 69 to switch on the latter at every odd field. Thereby, a color bar video signal obtained from a color bar video signal generator (not shown) is supplied to the magnetic head 31 through the input terminal 67, a mixer 70, a recording amplifier 71 and the change-over switch 72 and the switching circuit 69.
Accordingly, the color bar signal is recorded on forward- and backward-successive tracks fl, f3 ...... on the magnetic tape 11.
On the other hand, a change-over signal B going high at every even field as snown in Figure 5-B is formed at another output terminal Q of the flip-flop 73. The change-over signal B is supplied to the VT~ part II as a timing slgnal for changing over the magnetic head 33.
A VITC signal described hereinafter is supplied to another input of the mixer 70. The VITC signal is mixed in the mixer 70 with the color bar video signal and is inserted into each vertical blanking interval of the video signal. Thus, the VITC signal is recorded on each record tracks at each portion corresponding to the vertical blanking interval.
In the code recording mode, a capstan control signal _ is supplied from the processing circuit 53 to a capstan control circuit 56. The cpastan motor 36 of the VTR part I is inter-mittently driven with drive current supplied from the capstan control circuit 56. As above described, the code generator (not shown) is fixed on the rotary shaft of the capstan motor 36. The detecting output CG of the code generator is fed back to the capstan control circuit 56, so that the capstan motor 36 is so controlled as to rotate by a predetermined angle in one .
of the intermittent rotations. Also, the capstan motor 37 of the VTR part II is intermittently driven by a corresponding capstan control circuit in the same manner as the capstan motor 36 of the VTR part I.
Figure 5C and Figure 5D show wave forms of the drive current supplied to the capstan motors 36 and 37. The wave forms are substantially trian~ular as shown in Figure 5C and Figure 5D, so as to prevent steep acceleration and deceleration of the capstan motors 36 and 37 as much as possible. One drive , current is supplied to the capstan motor 36 of the VT~ part I in the even field, as shown in Figure 5C, while the other drive current is supplied to the capstan motor 37 of the VTR part II
in the odd field, as shown in Figure 5D. Thus, in the first - field, the magnetic tape 11 in the VTR part I stops~, while the head drum 2~ rotates one revolution to form the track fl on the magnetic tape 11 as shown in Figure 4-I. On the other hand, in the first field, the tape drive wheel 9 of the VTR part II is rotated by the predetermined angle by the capstan motor 37 to transport the magnetic tape 12 by two pitches of record tracks in the FW-direction.
Next, in the second field, the tape drive wheel 5 of the VTR part I is rotated by a predetermined angle by the capstan motor 36 to transport the magnetic tape 11 by two pitches of record tracks in the FW-direction. On the other hand, in the second field, the head drum 29 of the VTR part II rotates one revolution to form a track f2 on the magnetic tape 12 as shown in Figure 4-II. After that, in the same manner, the tracks f3, f5, ...... of the odd fields and the tracks f4, f6' ..... of the even fields are formed at two pïtches of record tracks alternately on the magnetic tapes 11 and 12, respectively.
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While the magnetic tape 11 is intermittently trans-ported in the FW direction, a switch SWl of the VTR I is closed with the control of the processing circuit 53 in Figure 3.
Accordingly, a record CTL signal d is supplied to a CTL record-ing circuit 57. A recording current E shown in Figure 5~ is formed on the basis of the record CTL signal d, and it is supplied from the CTL recording circuit 57 to the lower magnetic head F
of the CTL head 61 shown in Figure 2. In the odd field, namely, when the magnetic tape 11 has stopped, the direction of the recording current E is inverted from positive to negative. And in the even field, namely, when the magnetic tape 11 is being transported, the direction of the recording current E is in-verted from negative to positive. As a result, a CTL track CTL (FW) is formed on the lower marginal portion of the magnetic tape 11. The magnetization in the CTL track CTL (FW) is inverted . ,:
from N-polarity to S-polarity at a position corresponding to the track fl. When the magnetic tape 11 is being transported by the distance between the tracks fl and f3, the magnetization in the CTL track CTL (FW) is inverted from S-polarity to N-polarity. And the magnetization in the CTL track CTL (FW) is again inverted from N-polarity to S-polarity at a position corresponding to the track f3 in the condition that the magnetic tape 11 stops.
As schematicaIly shown in Figure 4-I, signals CTLl, CTL3, .. ....corresponding to the inversion positions from N-polarity to S-polarity are recorded at positions corresponding to the tracks fl, f3, ..... by the magnetic head F. While the magnetic tape 11 stops, the signals CTLl, CTL3, ...... are recorded on the magnetic tape 11. Accordingly, some slip between the tape drive wheel 5 and the magnetic tape 11 which is caused 14- !
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by the intermittent drive, has no adverse influence on the positional relationsh-ip between the tracks fl, f3, .... and the signals CTLl, CTL3, ..... , the magnetization may be inverted any time during the time of one field when the magnetic tape 11 stops. Accordingly, even when the inversion time of the CTL
signal d or recording current ~ varies a little, the positional relationship between the tracks fl, f3, .. ...and the si~nals CTLl, CTL3, .. ...is maintained constant. Further, tlle pulse widths of the negative and positive pulses of the recording current E do not need to be equal to each other. Slmilarly, another recording current shown in Figure 5F is supplied to the lower magnetic head F of the CTL head 62 in the VTR part II.
The recording current is opposite in phase to the recording current E. The magnetization is inverted from N-polarity to S-polarity during the time of the even field when the magnetic tape 12 stops. Signals CTL2, CTL~, ...... are recorded on the magnetic tape 12, corresponding to the trac~s f2, f4~ .
In the code recording mode, after the CTL signals end to be recorded in the forward direction in half of the selected time interval, CTL (BW) signals start to be recorded in the backward direction with control of the processing circuit 53.
In the last forward tape transport, the magnetic tape 11 is transported forward by one pitch of tracks, as shown in Figure 4-I, with the capstan control signal b from the processing circuit 53. And in the next odd field, the magnetic tape 11 is transported backward in the BW-direction by two pitches of tracks to form a track fn+2 on the magnetic tape 11, as shown in Figure 4-I. Thus, backward-successi~e tracks are formed between the adjacent two of the forward successive tracks fl, f3, ...... on the magnetic tape 11.
~3~3;2 The intermittent transport of the magnetic tape 11 in the backward direction is controlled with the CTL signal reproduced from the CTL (FW) track formed in the forward transport. In the backward transport, the switch SW 1 is opened, and switches SW 2 and SW 4 are closed, with the control of the processing circuit 53. Accordingly, CTL (BW) signals are recorded on the upper marginal portion of the magnetic tape 11 by the magnetic head B of the CTL head 61 to form a CTL (BW) track, while the CTL (FW) signals are repro-,: . .
duced from the CTL(FW) track formed on the lower marginal portionby the ma~netic head F of the CTL head 61. Wlth the intermittent baclcward transport of the magnetic tape 11, the CTL signals e is reproduced by the magnetic head F of the CTL head 61. In Figure 3, the reproduced CTL signal e from the magnetic head F
of the CTL head 61 is supplied to a CTL detecting circuit 53.
The positive differentiation pulses are selected at the CTL
detecting circuit 58, and is su?plied as a CTL signal f through the switch SW 2 to the capstan control circuit 56. The drive current c supplied from the capstan control circuit 56 is con-trolled on the basis of the CTL signal f, the capstan control signal _ and the output CG of the code generator respectively supplied to the capstan control circuit 56 to control the rotational angle of the capstan motor 36 in the reverse direction, and hence to control the stop position of the magnetic tape 11.
Thus, the baclcward-successive tracks fn+2 ..... are rightly formed midway between the adjacent two of the forward-successive tracks fl, f3, ..... , respectively. In that case, since the stop position of the magnetic tape 11 is controlled on the basis of the CTL signal f, the positional relationship between the record positions CTLl, CTL3, ...... in the forward CTL track and ` ` :` 113~432 .
- the backward-successive record tracks fn~2 ~ , are very accurate.
On the other hand, the record CTL signal d from the processing circuit 53 is supplied throu~h the switch SW4 to :;.
a CTL recording circuit 60 in the similar manner to the '-~ forward CTL recording operation. A recording current E, thepolarity of which is inverted at the period of one field as j shown in Figure 5E, is supplied from the CTL recording circuit ,; 60 to the magnetic head B of the CTL head 61. As a result, the backward CTL (BW) track is formed on the upper marginal , portion of the magnetic tape 11. Accordingly, CTL record spots CTLn~2 .. ., as shown by the dotted lines in Figure 4-I, are formed in correspondence with the backward-successive tracks . ~ .
fn+2~ ... The CTL record spots CTLl, CTL3, ...... on the forward CTL track positionally correspond to the tracks fl, f3, ..... . Further, the positional relationship between the CTL record spots CTLl, CTL3, ..... , the backward-successive tracks fn+2 ~ and the CTL record spots CTLn+2 ........... on the backward CTL track, are accurately regulated. Accordin~ly, also the positional relationship between the CTL record spots CTLn+2 ...... on the backward CTL track and the forward-successive tracks fl, f3, ...... is accurate.
Thus, as shown in Figure 6, first in the forward record-ing operation in the ~TR part I, a color bar video signal of an odd field in a frame numbered as 00 sec 00 F (Frame) is recorded on the first track fl of the magnetic tape 11, and then a video signal of a frame number 00 sec 01 F is recorded on the second track f3 of the magnetic tape 11 which is distant by two pitches of tracks from the first track. Hereafter, video signals of 00 sec 02 F, ..... .are recorded on the successive tracks of ; -17-.
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the maOnetic tape ll which are distant by two pitches from each other. A video signal of 14 sec 29 F is recorded on the last track of the magnetic tape 11. The last track is distant by one pitch of tracks from the previous track on which a video signal of a frame number l~ sec 28 F is recorded. ~ext, the magnetic tape ll is intermittently transported by two pitches of tracks in the backward direction to record video signals of frame numbers 15 sec 00 F, 15 sec 01 F, ..... ln order. And a video signal of a frame number 29 sec 29 F is recorded on the last of the backward-successive tracks distant by one pitch o:E tracks from the previous track on which a video signal of a frame number 29 sec 28 F is recorded.
Then, the ma~netic tape ll is transported by two pitches of tracks in the forward direction to the position where the magnetic head 31 traces the first track fl. In the VTR part II, in parallel with the VT~ part I, the video signal of each even field in the frames from 00 sec 00 F to 29 sec 29 F is recorded on each track of the tape 12. After that, the tape 12 is returned to the position where the magnetic head 32 traces the first track f2. Thus, one cycle of the code recording mode is accomplished. At that time, the ~rP~ is changed to the repro-ducing mode. The color bar signal of 00 sec 00 F recorded on the fi~st tracks fl and f2 is displayed as still picture.
In the code recording mode, the VITC signal corresnond-ing to the frame number (00 sec 00 F .... ) of each track is formed in the VITC signal generating circuit 7~ in digital code form. The VITC signal is recorded in the vertical blanking period of each track, as shown in Figure 7.
~ hen the code recording mode is finished, the recordedcolor bar video signal may be reproduced to moni-tor the repro-duced picture for checking up the presence of signal dropouts . ~
due to any damage of the coated surface of the tapes. The reproduction of the color bar is performed ~7ith the reproducing mode described hereinafter. T~len the signal dropouts occur, an .. ~
auto-feed button 76 of an auto-feed operation control part 75 is operated. A control signal is supplied to the processing circuit 53 through an auto-feed control circuit 77. On the basis of the above control signal, a capstan control signal b is formed, and it is supplied to the capstan control circuit 56, which controls the capstan motor 36 to feed the tape fast in the forward direction. When an output of a CTL detecting circuit 7$ for detecting the presence of the reproduced CTL
signal f goes low, the Lape feed stops. Then, the code record-ing button 66 of the recording operation control part 64 is again operated to record the CTL signal, VITC signal and color bar video signal on a new portion of the magnetic tape.
Recording Mode After the code recording mode is finished, the VTR is put into a recording mode with operation of a recording button 65 of the recording operation control part 6~. In the record-ing mode, the signal on the track fl which is traced with the magnetic head 31 of the head drum 28 is reproduced. A repro-duced video signal ~ is supplied to a VITC signal detecting circuit ~0 through a reproducing amplifier 79. The VITC
signal corresponding to 00 sec 00 F is read by the VITC signal detecting circuit 80. The VITC signal is supplied to the VITC signal generating circuit 74 to set the circuit 74 in the condition of the time code 00 sec 00 F of the signal _.
Then, the change-over switch 72 of Figure 3 is changed over to REC position and the VTR starts recording operation.
The video signal Vs is alternately recorded on the tracks fl, f3, ...... and f2, f~, ...... on the magnetic tapes 11 and 12 which are intermittently transported alternately in the VT2 I
and VTR II. New video signal Vs is recorded on the magnetic tapes 11 and 12 at the set repeat period of 30 seconds. In the recording mode, the VITC signal is recorded on each track in the same manner as the code recording mode. In Figure 3, the switches SW 1 and SW 4 are opened with control of the processing circuit 53. Further, in the forward transport of the magnetic tape 11, the switch SW 3 is closed, and in the backward transport of the magnetic tape 11, the switch Sl~ 2 is c~osed, with the control of the processing circuit 53.
Accordingly, in the forward recording mode, the stop position of the magnetic tape 11 is controlled with the CTL
signal obtained from the bac~ward CTL (~W) track, and the video si~nal is recorded on the trac~s fl, f3, ..... , while the magnetic head 31 scans the tracks fl, f3, ....... . In the backward recording mode, the stop position of the magnetic tape 11 is controlled with CTL signal obtained from the forward CTL (FW) track, and the video signal is recorded on the tracls fn+2 ~ while the magnetic head 31 scans the trac~s fn+2
BACKGROU~ID OF THE INVENTION
Field of the Invention This invention relates to a magnetic recording and reproducing device in which one of a recording head and a recording medium is intermittently transported relatively to the other in forward and backward directions to form record tracks on which a video signal is recorded and from which the video signal is reproduced.
Description of the Prior Art A video disc recorder (VDR) is known which has two rotational magnetic discs, respectively, having magnetic surfaces on both sides and four magnetic heads. Each of the magnetic heads is moved intermittently in the radial direction to form concentric circular record tracks spaced by a predeter-mined length from each other for recording a video signal and reproducing it. Each of the magnetic heads effects operations of erasing of record track, recording, reproducing and inter-mittent movement in order. The four heads operate at different timings in relation to the four operations. As the recording and reproducing operation of this device is carried out through the magnetic head stopped during ~he operations, no guard band noise occurs on the reproduction picture in a slow reproduction mode, still reproduction mode and reverse reproduction mode in which the rotational speeds of the magnetic disc are different. In such VDR, a reproduced picture of high quality can be obtained.
In the VDR, however, there are problems that the magnetic disc is relatively expensive and the life time of its magnetic surface is relatively short. Further, it takes about four seconds to find out the top or initiation of recorded scene 113~43~
for reproduction, since a pulse motor is used for the inter-mittent transportation of the magnetic head. That is incon-venient for practical use of such VDR. Further, as operation for finding the top is carried out by watching the reproduced picture, it further takes a great deal of time before repro-duction starts.
On the other hand, a VTR is known in which the position of a rotary magnetic head is controlled transversely to the scanning direction thereof in accordance with reducing tape speed for obtaining a reproduction picture containing no guard band noise. However, since some phase error is produced in the reproduced signal by controlling the position of the head, it is difficult in such VTR to obtain a reproduced picture of high quality.
BRIEF SUMMARY AND OBJECTS OF THE I~VENTION
The present invention relates to a magneti.c recording and reproducing device employing two magnetic tapes which are intermittently transported in forward and backward directions to form record tracks by a head on which a video signal is recorded and from which the video signal is reproduced. Means is provided which includes an identification code recording and reproducing means to record and reproduce an identification code on or from a part of each record track with the video signal ` for identifying each of the record tracks. Memory means is included to memorize the identification code in accordance with the operation of a first operating means to be employed in the recording operation, the identification code being of a code at a point of time when the first operating means is operated. Distance detecting means is included to detect the .'~ I
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relative moving distance between the recording head and the recording medium in accordance with the operation of a second operating means which functions in the recording operation, on the basis of another identification code at a point of time when the second operating means is operated and the identification code memorized in the memory means. A returning movement control means to control the relative returning movement of the record medium to the position identified by the code at the time when the first operating means is operated, in accordance with the output of the distance detecting means, the returning move-ment being controlled so as to be carried out at a predetermined speed and then having intermittent movement when the relative distance reaches a predetermined value. Coincidence detecting means is also provided to detect the coincidence of a reproduced identification code obtained from the identification recording and reproducing means, then the identification code memorized in the memory means during the intermittent returning movement. A
returning movement stop signal is supplied to the returning movement control means. The device provides a tape control system using an address signal inserted in the video signal and control track signals so as to transport the tape faster . . , and accurately to the predetermined position.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a plan view of a VTR according to one embodiment of the present invention;
Figure 2 is a front view of a CTL head in Figure l;
Figure 3 is a block diagram of a drive control circuit for the VTR of Figure l;
Figure 4I and Figure 4II are partial plan views of a~
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magnetic tape on which record tracks are formed;
Figure 5 is a waveform of signals at the respective parts in Figure 3;
- Figure 6 is a view for explaining the scanning order of the record tracks;
Figures 7-A to 7-D and A' to D' are views for explaining the positional relationships between start tracks and stop tracks in the recording mode; and Figure 8 is a graph showing tape speed in the search mode for searching the start track.
DESCRIPTIO~ OF THE PRF.FERRED E~BODI~ ITS
Figure 1 is a plan view of a VTR according to a pre-ferred embodiment of this invention. This VTR consists of two VTR parts I and II. The one VTR part includes a first tape running system 1. The other VTR part includes a second tape running system 2. The first tape running system 1 is constituted by a supply reel (take-up reel) 3, a head drum assembly 4, a ~:, tape drive wheel 5 and a take-up reel (supply reel) 6. Similarly, the second tape running systen 2 is constituted by a supply reel (take-up reel) 7, a head drum assembly 8, a tape drive wheel 9 and a take-up reel (supply reel) 10. A pair of accumulators (vacuum columns) 13 and 14 are arranged between the first tape running system 1 and the second tape running system 2. Portions of magnetic tapes 11 and 12 threaded through the respective tape running systems 1 and 2 are temporarily stored in the accumulators 13 and 14 by vacuum action of the latter.
The four reels 3, 6, 7 and 10 are of the open-reel type.
The magnetic tapes 11 and 12 are wound on hubs of the reels 3, 6, 7 and 10, respectively. In the first tape running system 1, 1139~3Z
the magnetic tape 11 fed from the supply reel 3 is guided through a predetermined tape running path by guide pins 15, 16, 17, 18, 19 and 20. Similarly, in the second tape running system 2, the magnetic tape 12 is guided through another pre-determined tape running path by guide pins 21, 22, 23, 24, 25 and 26. The predetermined tape running paths of the first and second tape running systems 1 and 2 are symmetrical to each other in the VTR according to this embodiment.
In the first tape running system 1, control track 61 (CTL head) is arranged between the guide pins lS and 19 so as to contact with the magnetic tape 11. Similarly, in the second tape running system 2, another CTL head 62 is arranged between the guide pins 24 and 25 so as to contact with the magnetic tape 12. The CTL heads 61 and 62 are the ones which can record signals on, and reproduce signals from the magnetic tapes 11 and 12. Figure 2 is a front view of the CTL head 61 which has the same structure as the other CTL head 62. As shown in Figure 2, the CTL head 61 includes an upper magnetic head B
and a lower magnetic head F which are opposite to the upper and lower marginal portions of the magnetic tape 11 shown by the chain line in Figure 2. The magnetic heads B and F are located substantially at the same position with respect to the longi-tudinal direction (running direction) of the magnetic tape 11.
The rotary head drum assembly 4 includes a head drum 28 which is rotated in the clockwise direction. The other rotary head drum assembly 8 includes a head drum 29 which is rotated in the counter-clockwise direction. The rotational directions of the head drums 28 and 29 are in the running directions of the magnetic tapes 11 and 12. A magnetic head 31 is attached to a part of the peripheral portion of the head .:, ,:
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drum 2~. An erasing ma~netic head 32 is attached to the peripheral portion of the head drum 28 adjacent to the magnetic head 31. The magnetic erasing head 32 runs alon~ substantially the same scanning path as the magnetic head 31. Similarly, a magnetic head 33 and a magnetic erasing head 34 are attached to a part of the peripheral portion of the head drum 29, adjacent to each other. The magnetic heads 31 and 33 follow the magnetic erasing heads 32 and 3~ with respect to the rotational direction of the head drums 23 and 29, respectively. While the previously recorded signals are erased from the magnetic tape 10 or 11 by the magnetic erasing head 32 or 34, new signals are recorded on the magnetic tape 10 or 11 by the magnetic heads 31 and 33.
The tape drive wheel 9 for intermittently feeding the magnetic tape 12 is arranged near the head drum assembly 8, and it is in the form of cylindrical roller having a smaller diameter than the rotary head drum 29. Rubber is attached to the cir-cumferential surface of the drive wheel 9 to impart a consider-able frictional force to the magnetic tape 12. The tape drive wheel 9 is intermittently driven by a capstan motor 37 directly connected to the drive wheel 9.
The tape drive wheel 5 in the first tape running system 1 has the same structure as the tape drive wheel 9 in the second .. ..
tape running system 2. Similarly, it is intermittently driven by a capstan motor 36 directly connected to itself. The capstan motors 36 and 37 are, for example, DC motors. Code generators for detecting rotational angles of the motors 36 and . . ,~
i 37 are fixed to rotary shafts of the motors 36 and 37. The ~.
~ rotations of the motors 36 and 37 are controlled with the - detecting outputs of the code generators.
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Next, there will be described the accumulators 13 and 14 arranged between the first tape running system 1 and the second tape running system 2.
Through holes 38 and 39 are made in the accumulators 13 and 14 along the lengthwise directions of the accumulators 13 and 14, respectively. The through holes 3~ and 39 have rectangular cross-section the width of which is nearly equal to the width of the magnetic tapes 11 and 12. Air in the through holes 38 and 39 is sucked through pipes 40 and 41 by not-shown vacuum pumps, so that the slackened magnetic tapes 11 and 12 are guided into the through holes 38 and 39 in the form of letter U.
A pair of sensing elements 42 and 43 for detecting the magnetic tapes 11 and 12 are arranged at the side of the accumulator 13. A reel motor 44 to drive the reel 3 is rotated upon detecting output of the sensing element 42. And a reel motor 45 to drive the reel 7 is rotated upon detecting output of the sensing element 43. Similarly, another pair of sensing elements 46 and 47 for detecting the magnetic tapes 11 and 12 are arranged at the side of the other accumulator 14.
A reel motor 48 to drive the reel 6 is rotated upon detecting output of the sensing element 46. And a reel motor 49 to drive the reel 10 is rotated upon detecting output of the sensing element 47. Accordingly, portions of the magnetic tapes 11 and 12 of substantially predetermined length are always stored in .
the accumulators 13 and 14.
The magnetic tapes 11 and 12 are wrapped helically and entirely around the head drums 2~ and 29 in the form of letter a (alpha). Accordingly, record tracks are formed on the magnetic tapes 11 and 12 at a predetermined angle to the longi-.:.
~ tudinal direction of the magnetic tapes 11 and 12. In the ,'.
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recording operation and the reproducing operation, the magnetic heads scan the magnetic tapes 11 and 12 while they are stopped, respectively. Accordin~ly, the angles of the scanning paths of the magnetic heads in the recording operation and the reproducing operation are equal to each other regardless of tape running speed in the reproducing operation. No noise band occurs on the reproduced picture in any of the still re?roduction, the slow-motion reproduction and the reverse-motion reproduction.
Next, operations of the VTR according to this embodi-ment will be described with reference to Figure 3 to Figure 8.
.
Figure 3 is a block diagram of a drive control circuit for the VTR part I shown in Figure 1. Another drive control circuit for the VTR part II shown in Figure 1 is equal to that for the VTR part I in construction. And the former operates in a similar manner to the latter except that the former's operation is different in timing from the latter's operation.
Figure 4-I and Figure 4-II are plan views of respective parts of the magnetic tapes 11 and 12 on which record tracks are formed, respectively. Figure 5 is wave forms of signals at the respective parts of the block diagram of Figure 3.
Figure 6 is a view for explaining the scanning order o~ the record tracks. Figures 7-A to 7-D and 7-A' to 7-D' are views for explaining the relationships between start tracks and stop tracks in the recording mode. And Figure 8 is a graph showing tape speed in the search mode for searching the start track.
In the recording operation and reproducing operation of the VTR according to this embodiment, the magnetic tapes 11 and 12 are transported forward and backward in a selected, predetermined time interval. In the VTR part I, when the mag-netic tape 11 is transported in the FW (forward) direction shown .
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by the arrow in Figure R-I, record tracks fl~ f3 fn shown by the solid lines are successively formed on the ma~netic tape 11. And when the magnetic tape 11 is transported in the BW
(backward) direction shown by the arrow BW in Figure 4-I, record tracks fn+2 ---- shown by the dotted lines are successively formed between the adjacent record-tracks shown by the solid lines on the magnetic tape 11. Also in the VTR
part II, record tracks are formed on the magnetic tape 12 in a similar manner. The VTR parts I and II alternately operate every one field of video signals. Video signals of odd fields are recorded on the magnetic tape 11 in the VTR part I, while video signals of even fields are recorded on the magnetic tape lZ in the VTR parts II.
In Figure 3, one of selecting buttons 51a, 51b, 51c and 51d in a time interval selection circuit 51 is selectively pushed to set the time interval of the recording operation.
For example, time intervals of 30 seconds, 60 seconds, 2 minutes and 5 minutes can be set by the selec~ing buttons 51a, 51b, 51c and 51d, respectively. When the selecting button 51a is pushed, the magnetic tapes 11 and 12 are transported forward and backward in the time interval of 30 seconds. In other words, the magnetic tapes 11 and 12 are transported one way, namely forward or backward in 15 seconds. New video signals are successively recorded on the magnetic tapes 11 and 12 in the time interval of 30 seconds .
;:~ Next, operations of the VTR of this embodiment will be ~ described in relation to the code recording mode, the recording :, mode and the reproducing mode.
(1), Code Recording Mode In the VTR according to this embodiment, a C~L signal, ~13~g3Z
a VITC (Vertical Interval Time Code) signal and a color bar video signal are recorded on the magnetic tapes 11 and 12 before video signals start to be recorded on the ma~net tapes 11 and 12. Such recording operation is hereinafter called as "code recording mode". Other address signals which can be inserted in the video signal can be used instead of VITC signal, such, for example, as the address signal shown in Tachi u.s. Patent 4,159,480, assigned to the same assignee as the present a?plication.
l~hen a code recording mode button 66 of a recording operation control part 64 is pushed in Figure 3, a code record-ing mode set signal is supplied through the button 66 to a pro-cessing circuit 53 to put the VTR into the code recording mode.
A siznal a having the vertical frequency of 60Hz is supplied from the processing circuit 53 to a drum servo circuit 54. A
drum motor 55 is rotated at the speed of 60Hz with the output of the drum servo circuit 54. Accordingly, the head drum ~8 for the VTR part I shown in Figure 1 is driven at the vertical ... .
frequency. The head drum ~9 for the VTR part II is rotated in the same manner.
; A video signal Vs is supplied to a vertical synchroniz-` ing signal separating circuit 68 through an input ter~inal 67 ofi; the drive control circuit of Figure 3. A vertical synchronizing signal VD separated through the separating circuit 67 is supplied to the processing circuit 53, so that the operation of the pro-cessing circuit 53 is synchronized with the vertical synchron-izing signal VD.
' A change-over switch 72 in Figure 3 is connected to REC
position in the code recording mode. The vertical synchronizing signal VD is supplied to a clock input terminal CP of a flip-flop -.
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73, so that a change-over signal A going high at every odd field as shown in Figure 5-A is formed at an output terminal ~ thereof.
The change-over signal A is supplied to a switching circuit 69 to switch on the latter at every odd field. Thereby, a color bar video signal obtained from a color bar video signal generator (not shown) is supplied to the magnetic head 31 through the input terminal 67, a mixer 70, a recording amplifier 71 and the change-over switch 72 and the switching circuit 69.
Accordingly, the color bar signal is recorded on forward- and backward-successive tracks fl, f3 ...... on the magnetic tape 11.
On the other hand, a change-over signal B going high at every even field as snown in Figure 5-B is formed at another output terminal Q of the flip-flop 73. The change-over signal B is supplied to the VT~ part II as a timing slgnal for changing over the magnetic head 33.
A VITC signal described hereinafter is supplied to another input of the mixer 70. The VITC signal is mixed in the mixer 70 with the color bar video signal and is inserted into each vertical blanking interval of the video signal. Thus, the VITC signal is recorded on each record tracks at each portion corresponding to the vertical blanking interval.
In the code recording mode, a capstan control signal _ is supplied from the processing circuit 53 to a capstan control circuit 56. The cpastan motor 36 of the VTR part I is inter-mittently driven with drive current supplied from the capstan control circuit 56. As above described, the code generator (not shown) is fixed on the rotary shaft of the capstan motor 36. The detecting output CG of the code generator is fed back to the capstan control circuit 56, so that the capstan motor 36 is so controlled as to rotate by a predetermined angle in one .
of the intermittent rotations. Also, the capstan motor 37 of the VTR part II is intermittently driven by a corresponding capstan control circuit in the same manner as the capstan motor 36 of the VTR part I.
Figure 5C and Figure 5D show wave forms of the drive current supplied to the capstan motors 36 and 37. The wave forms are substantially trian~ular as shown in Figure 5C and Figure 5D, so as to prevent steep acceleration and deceleration of the capstan motors 36 and 37 as much as possible. One drive , current is supplied to the capstan motor 36 of the VT~ part I in the even field, as shown in Figure 5C, while the other drive current is supplied to the capstan motor 37 of the VTR part II
in the odd field, as shown in Figure 5D. Thus, in the first - field, the magnetic tape 11 in the VTR part I stops~, while the head drum 2~ rotates one revolution to form the track fl on the magnetic tape 11 as shown in Figure 4-I. On the other hand, in the first field, the tape drive wheel 9 of the VTR part II is rotated by the predetermined angle by the capstan motor 37 to transport the magnetic tape 12 by two pitches of record tracks in the FW-direction.
Next, in the second field, the tape drive wheel 5 of the VTR part I is rotated by a predetermined angle by the capstan motor 36 to transport the magnetic tape 11 by two pitches of record tracks in the FW-direction. On the other hand, in the second field, the head drum 29 of the VTR part II rotates one revolution to form a track f2 on the magnetic tape 12 as shown in Figure 4-II. After that, in the same manner, the tracks f3, f5, ...... of the odd fields and the tracks f4, f6' ..... of the even fields are formed at two pïtches of record tracks alternately on the magnetic tapes 11 and 12, respectively.
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While the magnetic tape 11 is intermittently trans-ported in the FW direction, a switch SWl of the VTR I is closed with the control of the processing circuit 53 in Figure 3.
Accordingly, a record CTL signal d is supplied to a CTL record-ing circuit 57. A recording current E shown in Figure 5~ is formed on the basis of the record CTL signal d, and it is supplied from the CTL recording circuit 57 to the lower magnetic head F
of the CTL head 61 shown in Figure 2. In the odd field, namely, when the magnetic tape 11 has stopped, the direction of the recording current E is inverted from positive to negative. And in the even field, namely, when the magnetic tape 11 is being transported, the direction of the recording current E is in-verted from negative to positive. As a result, a CTL track CTL (FW) is formed on the lower marginal portion of the magnetic tape 11. The magnetization in the CTL track CTL (FW) is inverted . ,:
from N-polarity to S-polarity at a position corresponding to the track fl. When the magnetic tape 11 is being transported by the distance between the tracks fl and f3, the magnetization in the CTL track CTL (FW) is inverted from S-polarity to N-polarity. And the magnetization in the CTL track CTL (FW) is again inverted from N-polarity to S-polarity at a position corresponding to the track f3 in the condition that the magnetic tape 11 stops.
As schematicaIly shown in Figure 4-I, signals CTLl, CTL3, .. ....corresponding to the inversion positions from N-polarity to S-polarity are recorded at positions corresponding to the tracks fl, f3, ..... by the magnetic head F. While the magnetic tape 11 stops, the signals CTLl, CTL3, ...... are recorded on the magnetic tape 11. Accordingly, some slip between the tape drive wheel 5 and the magnetic tape 11 which is caused 14- !
3;~
by the intermittent drive, has no adverse influence on the positional relationsh-ip between the tracks fl, f3, .... and the signals CTLl, CTL3, ..... , the magnetization may be inverted any time during the time of one field when the magnetic tape 11 stops. Accordingly, even when the inversion time of the CTL
signal d or recording current ~ varies a little, the positional relationship between the tracks fl, f3, .. ...and the si~nals CTLl, CTL3, .. ...is maintained constant. Further, tlle pulse widths of the negative and positive pulses of the recording current E do not need to be equal to each other. Slmilarly, another recording current shown in Figure 5F is supplied to the lower magnetic head F of the CTL head 62 in the VTR part II.
The recording current is opposite in phase to the recording current E. The magnetization is inverted from N-polarity to S-polarity during the time of the even field when the magnetic tape 12 stops. Signals CTL2, CTL~, ...... are recorded on the magnetic tape 12, corresponding to the trac~s f2, f4~ .
In the code recording mode, after the CTL signals end to be recorded in the forward direction in half of the selected time interval, CTL (BW) signals start to be recorded in the backward direction with control of the processing circuit 53.
In the last forward tape transport, the magnetic tape 11 is transported forward by one pitch of tracks, as shown in Figure 4-I, with the capstan control signal b from the processing circuit 53. And in the next odd field, the magnetic tape 11 is transported backward in the BW-direction by two pitches of tracks to form a track fn+2 on the magnetic tape 11, as shown in Figure 4-I. Thus, backward-successi~e tracks are formed between the adjacent two of the forward successive tracks fl, f3, ...... on the magnetic tape 11.
~3~3;2 The intermittent transport of the magnetic tape 11 in the backward direction is controlled with the CTL signal reproduced from the CTL (FW) track formed in the forward transport. In the backward transport, the switch SW 1 is opened, and switches SW 2 and SW 4 are closed, with the control of the processing circuit 53. Accordingly, CTL (BW) signals are recorded on the upper marginal portion of the magnetic tape 11 by the magnetic head B of the CTL head 61 to form a CTL (BW) track, while the CTL (FW) signals are repro-,: . .
duced from the CTL(FW) track formed on the lower marginal portionby the ma~netic head F of the CTL head 61. Wlth the intermittent baclcward transport of the magnetic tape 11, the CTL signals e is reproduced by the magnetic head F of the CTL head 61. In Figure 3, the reproduced CTL signal e from the magnetic head F
of the CTL head 61 is supplied to a CTL detecting circuit 53.
The positive differentiation pulses are selected at the CTL
detecting circuit 58, and is su?plied as a CTL signal f through the switch SW 2 to the capstan control circuit 56. The drive current c supplied from the capstan control circuit 56 is con-trolled on the basis of the CTL signal f, the capstan control signal _ and the output CG of the code generator respectively supplied to the capstan control circuit 56 to control the rotational angle of the capstan motor 36 in the reverse direction, and hence to control the stop position of the magnetic tape 11.
Thus, the baclcward-successive tracks fn+2 ..... are rightly formed midway between the adjacent two of the forward-successive tracks fl, f3, ..... , respectively. In that case, since the stop position of the magnetic tape 11 is controlled on the basis of the CTL signal f, the positional relationship between the record positions CTLl, CTL3, ...... in the forward CTL track and ` ` :` 113~432 .
- the backward-successive record tracks fn~2 ~ , are very accurate.
On the other hand, the record CTL signal d from the processing circuit 53 is supplied throu~h the switch SW4 to :;.
a CTL recording circuit 60 in the similar manner to the '-~ forward CTL recording operation. A recording current E, thepolarity of which is inverted at the period of one field as j shown in Figure 5E, is supplied from the CTL recording circuit ,; 60 to the magnetic head B of the CTL head 61. As a result, the backward CTL (BW) track is formed on the upper marginal , portion of the magnetic tape 11. Accordingly, CTL record spots CTLn~2 .. ., as shown by the dotted lines in Figure 4-I, are formed in correspondence with the backward-successive tracks . ~ .
fn+2~ ... The CTL record spots CTLl, CTL3, ...... on the forward CTL track positionally correspond to the tracks fl, f3, ..... . Further, the positional relationship between the CTL record spots CTLl, CTL3, ..... , the backward-successive tracks fn+2 ~ and the CTL record spots CTLn+2 ........... on the backward CTL track, are accurately regulated. Accordin~ly, also the positional relationship between the CTL record spots CTLn+2 ...... on the backward CTL track and the forward-successive tracks fl, f3, ...... is accurate.
Thus, as shown in Figure 6, first in the forward record-ing operation in the ~TR part I, a color bar video signal of an odd field in a frame numbered as 00 sec 00 F (Frame) is recorded on the first track fl of the magnetic tape 11, and then a video signal of a frame number 00 sec 01 F is recorded on the second track f3 of the magnetic tape 11 which is distant by two pitches of tracks from the first track. Hereafter, video signals of 00 sec 02 F, ..... .are recorded on the successive tracks of ; -17-.
3~
the maOnetic tape ll which are distant by two pitches from each other. A video signal of 14 sec 29 F is recorded on the last track of the magnetic tape 11. The last track is distant by one pitch of tracks from the previous track on which a video signal of a frame number l~ sec 28 F is recorded. ~ext, the magnetic tape ll is intermittently transported by two pitches of tracks in the backward direction to record video signals of frame numbers 15 sec 00 F, 15 sec 01 F, ..... ln order. And a video signal of a frame number 29 sec 29 F is recorded on the last of the backward-successive tracks distant by one pitch o:E tracks from the previous track on which a video signal of a frame number 29 sec 28 F is recorded.
Then, the ma~netic tape ll is transported by two pitches of tracks in the forward direction to the position where the magnetic head 31 traces the first track fl. In the VTR part II, in parallel with the VT~ part I, the video signal of each even field in the frames from 00 sec 00 F to 29 sec 29 F is recorded on each track of the tape 12. After that, the tape 12 is returned to the position where the magnetic head 32 traces the first track f2. Thus, one cycle of the code recording mode is accomplished. At that time, the ~rP~ is changed to the repro-ducing mode. The color bar signal of 00 sec 00 F recorded on the fi~st tracks fl and f2 is displayed as still picture.
In the code recording mode, the VITC signal corresnond-ing to the frame number (00 sec 00 F .... ) of each track is formed in the VITC signal generating circuit 7~ in digital code form. The VITC signal is recorded in the vertical blanking period of each track, as shown in Figure 7.
~ hen the code recording mode is finished, the recordedcolor bar video signal may be reproduced to moni-tor the repro-duced picture for checking up the presence of signal dropouts . ~
due to any damage of the coated surface of the tapes. The reproduction of the color bar is performed ~7ith the reproducing mode described hereinafter. T~len the signal dropouts occur, an .. ~
auto-feed button 76 of an auto-feed operation control part 75 is operated. A control signal is supplied to the processing circuit 53 through an auto-feed control circuit 77. On the basis of the above control signal, a capstan control signal b is formed, and it is supplied to the capstan control circuit 56, which controls the capstan motor 36 to feed the tape fast in the forward direction. When an output of a CTL detecting circuit 7$ for detecting the presence of the reproduced CTL
signal f goes low, the Lape feed stops. Then, the code record-ing button 66 of the recording operation control part 64 is again operated to record the CTL signal, VITC signal and color bar video signal on a new portion of the magnetic tape.
Recording Mode After the code recording mode is finished, the VTR is put into a recording mode with operation of a recording button 65 of the recording operation control part 6~. In the record-ing mode, the signal on the track fl which is traced with the magnetic head 31 of the head drum 28 is reproduced. A repro-duced video signal ~ is supplied to a VITC signal detecting circuit ~0 through a reproducing amplifier 79. The VITC
signal corresponding to 00 sec 00 F is read by the VITC signal detecting circuit 80. The VITC signal is supplied to the VITC signal generating circuit 74 to set the circuit 74 in the condition of the time code 00 sec 00 F of the signal _.
Then, the change-over switch 72 of Figure 3 is changed over to REC position and the VTR starts recording operation.
The video signal Vs is alternately recorded on the tracks fl, f3, ...... and f2, f~, ...... on the magnetic tapes 11 and 12 which are intermittently transported alternately in the VT2 I
and VTR II. New video signal Vs is recorded on the magnetic tapes 11 and 12 at the set repeat period of 30 seconds. In the recording mode, the VITC signal is recorded on each track in the same manner as the code recording mode. In Figure 3, the switches SW 1 and SW 4 are opened with control of the processing circuit 53. Further, in the forward transport of the magnetic tape 11, the switch SW 3 is closed, and in the backward transport of the magnetic tape 11, the switch Sl~ 2 is c~osed, with the control of the processing circuit 53.
Accordingly, in the forward recording mode, the stop position of the magnetic tape 11 is controlled with the CTL
signal obtained from the bac~ward CTL (~W) track, and the video si~nal is recorded on the trac~s fl, f3, ..... , while the magnetic head 31 scans the tracks fl, f3, ....... . In the backward recording mode, the stop position of the magnetic tape 11 is controlled with CTL signal obtained from the forward CTL (FW) track, and the video signal is recorded on the tracls fn+2 ~ while the magnetic head 31 scans the trac~s fn+2
(2)-A Start ~Iode In the recording mode, when a start switch 81 in Figure
3 is pushed, the VT~ is put into a start mode. The start switch 81 may be operated in the case when searching of the top or initiation of a desired scene to be recorded is required. At the point of the time when the start switch 81 is pushed, the time code, that is, an outpu~ of the VITC signal generating circuit 74 is memorized in a memory S2. The content of the memory 82 is supplied to a comparator 83. On the other hand, the output of the VITC signal generating circuit 74 is supplied to - ~139~3~
an input terminal A of a selector 84. A control signal is :~ supplied to a control terminal K of the selector 84 from the processing circuit 53 after the start switch 81 is operated.
With the control signal, the input terminal A is selected in .
the selector 84. Accordingly, in the start mode, the output of the VITC signal generating circuit 74 is supplied to another input of the comparator 8~ through the selector 84. Thus, after the selected period of 30 seconds has passed since the point of time when the start switch 81 is pushed, the time code of the output of the VITC signal generating circuit 74 coincides with the time code of the content in the memory 32. As a result, a coincidence signal is supplied from the comparator 83 to the processing circuit 53, which produces a capstan control signal b to stop the capstan motor 36. Thus, the transport of the tape 11 stops and the recording operation is finished.
Thus, only one cycle of recording operation for the time period designated by the interval selection circuit 51 is performed after the start switch 81 is operatcd. Accordingly, there is no trouble of missing the desired recording scene through careLessness. Further, since the top of the recorded scene is found out at the time when the recording operation is finished, the VTR may immediately start the reproducing operation from the top of the recorded scene.
The output of the VITC signal generating circuit 74 is supplied to a display unit 85. The display unit 85 consists of, for example, plural display elements, for example, light emitting diodes, arranged in a line. These elements light in order to form a bar-graph-like display in accordance with change of the VITC signal. The whole lighting (full scale) of the display unit 85 corresponds to the period designated : ~13~32 ` :-through the interval selection circuit 51. Therefore, by monitoring the display unit 85 for the scene to be recorded, - the start switch 81 may be operated again to secure another one cycle of the recording period when the desired scene to be recorded seems to become longer.
:
Search Mode When a stop switch 89 is pushed within the selected recording period (30 seconds, for example) in the start mode, ` the VTR is put into a search mode for finding out the record track identified by the time code corresponding to the time when the start switch 81 is operated. When the stop switch 89 is pushed, the time code at the point of time, that is, the output of the VITC signal generating circuit 74, is supplied to the processing circuit 53 through the stop switch 89, and is memorized in a memory in the processing circuit 53.
The recording operation of the VTR is stopped with the control of the processin~ circuit 53 at the time when the stop switch ;~ 89 is operated. In the processin~ circuit 53, there is per-formed a calculation of the distance between the start track and the stop track on the magnetic tape on the basis of the content of the memory memorizinv the time code corresponding ` to the time when the stop switch 89 is operated and the con-tent of the memory 82 memorizing the time code corresponding to the time when the start switch 81 is operated.
Figures 7-A to 7-D and Figures 7-A' to 7-D' show the positional relationships between the start tracks fs and the stop tracks fe. Figures 7-A to 7-D show the cases where the start track is is situated at one of the forward successive - tracks fl, f3, ..... , and Figures 7-A' to 7-D' show the cases when the start track fs is situated at one of the backward ;~ ~13~432 .
successive tracks fn+2 ...... . In the calculation of the distance between the start track fs and the stop track feJ
difference (T) between respective corresponding time codes ts and te~ namely, T = te ~ ts. is calculated.
As a positive result, T is obtained by the calcula-tion in the cases A and A', the magnetic tape is moved for searching in the direction opposite to the direction of the tape transportation to form the successive-tracks containing the start track fs. Namely, in Figure 7-A, the magnetic tape is moved in the backward direction, fs~ fe~ to search the top of the reproducing scene, and in Figure 7-A', the magnetic ta~e is moved in the forward direction, fe~ fs- to search the top of the reproducing scene.
Since the distance T can not be directly calculated in the cases shown in Figures 7-B and 7-B'; the time code te of the stop track fe is exchanged to a time code te' of the track being adjacent to the stop track fe. Namely, in Figure 7-B, the time code te is exchanged to the corresponding time code of the adjacent forward successive track fe' and in Figure 7-B', the time code te is exchanged to the correspond-ing time code of the adjacent backward successive-track fel, and then, distance T between fs and fe' is calculated. The exchange of the time code may be performed through an encoder which exchange the code between the forward successive tracks and the backward successive tracks. The code exchange may be carried out in response to the detection of turning of the tape transportation. As a positive result, T is obtained by the calculation : T = te' - ts, the tape ls moved for searching in the backward direction fs~ fe as in Figure 7-B, or in the forward direction fe~ fs as in Figure 7-B', in the ~39!43~
same manner as Figures 7-A or 7_~1.
Si~ilarly, in the cases of Figures 7-C and 7-C', the time code of the stop track fe is exchanged to that of the adjacent successive track on the start side, and then, the ; distance T is calculated. Since the difference T shows a negative value, the tape is moved in the forward direction fe~ fs in the case C and in the bac~ward direction fs~ fe in the case c", that is, in opposite direction to the cases A, A' and B, B'.
In the cases of Figures 7-D and 7-D', since the direction of direction of tape transportation is turned twice, the exchange of the time code o~ the stop track fe is not required. The exchange of time code may be carried out only when the turning of the direction of tape transportation is once effected. The distance T = te ~ ts is directly calculated in the cases D and D'. The distance T shows a negative value in each case, and so the tape is moved for searching in the direction fe~ fs in the case D, and in the direction fs~ fe in the case D', in the opposite manner to the cases A and A'.
Thus, the tape feed direction for the searchin~ is determined in accordance with negative or positive sign of the distance T and the number of turnings of the tape transporta-tion. Further, the tape feed speed is determined in accordance with the value of calculated distance T in the processing circuit 53. For example, as shown in Figure 8, when the distance T shows more than 100 frames, the tape is continuously fed at a first feed speed Vs until the distance becomes less than 100 frames. Then, the tape is continuously fed at a second feed speed Vf until the difference becomes less than lq frames.
After that, the tape is intermittently transported for searching :'' .
~ ~ 3~3~
the top of the reproducing scene during the 10 frames.
- In that search mode, the reproduced CTL signals are subtracted one by one from the calculated distance T to detect the positions being of 100 frames and 10 frames far from the start track fs~ when the tape is fed at the first feed speed Vs and the second feed speed Vf. After the result of sub-traction becomes less than 10 frames, the tape is intermittently transported and each stop position of the tape is controlled with servo control to the capstan motor 36 on the basis of the reproduced CTL signal f. In this case, the CTL signal on the CTL track for the successive-tracks opposite to the start track fs is used. Therefore, for example, when the start track fs is included in the forward successive tracks, a reproducing signal obtained from the backward CTL track CTL (B~J) i is used for the servo control. Though there is some mis-tracking at the time when the tape feeding condition is changed to the intermittent transportation from the continuous feeding, an accurate tracking is achieved through the capstan servo control, so that the VITC signal can be detected by the tracking.
In Figure 3, when the VTR is put into the search mode by operating the stop switch 89, a B input is selected in the selector 84 by a control signal from the processing circuit 53. Therefore, the VITC signal detected through the VITC
signal detecting circuit 80 is supplied to the comparator 83 through the selector 84. To another input of the comparator 83, the VITC signal of the start track memorized in the memory 82 is supplied. The top of the recorded scene can be found out by detecting the coincidence of the VITC signal and the content of the memory 82 with each other. The output of the 113~43Z
comparator 83 is supplied to the processing circuit 53, which generates a capstan control signal b to stop the intermittent transportation of the capstan motor 36.
(3), Reproducing Mode The VT~ may be put into a reproducing mode after the search mode is finished. The reproducing mode is automatically obtained after the top of the recorded scene has been found out through the search mode. Alternatively, the VTR may be put into a stop mode after the finish of the search mode, and the VTR may be put into the reproducing mode with operation of a reproducing button (not shown). In the reproducing mode, the change over switch 72 is switched to PB position. Accord-ingly, a reproduced signal obtained from the magnetic head 31 is led out from an output terminal 91 through the switching circuit 69, the change-over switch 72, the reproducing ampli-fier 79 and a selector 90. The selector 90 is provided to change over alternately the reproduced signals from the VTR
part I and VTR part II at every field. The selector 90 is controlled by a change-over signal formed on the basis of the output PG of the pulse generator for detecting the rotational position of the drum motor 55.
Tape runnin~ speed in the reproduction is selected through a tape speed selection control part 92. The output of the control part 92 is supplied to the processing circuit 53, which generates a capstan control signal b to determine . the period of the intermittent drive of the capstan motor 36.
- The slow reproduction mode, the still reproduction mode and the i normal reproduction mode are selected by operating the tape speed selection control part 92. In these reproduction modes, the reproduced VITC signal is supplied from the VITC signal ~ ' ~3~3;Z
detecting circuit 80 to the display unit 85 which has plural display elements arranged in a line to form a bar-graph-like display such as used in the recording operation. The scanning position of the record tracks can be recognized by light-out of the display elements in order in accordance with change of the VITC signal. Further, the VITC signal is supplied to a time display part 93 through the processing circuit 53 to display the frame number of the reproducing track.
In the reproducing mode, each stopping position of the intermittent transportation of the tape is controlled on ~;, the basis of CTL signal recorded in the code recording mode to trace the record track for reproduction of the recorded signal. The reproduced VITC signal from the VITC signal detecting circuit ~0 is supplied to the processing circuit 53 to be compared with the VITC signal memorized in the pro-cessing circuit 53, that is, the time code of the stop track fe at the point of time when the stop switch 89 is pushed.
When the reproduced VITC signal coincides with the memorized VITC signal, the reproduction for the desired scene is over, and next operation is performed in accordance with operation of a reproducing operation control part 94.
When a stop button 95 of the reproducing operation control part 94 has been pushed, the tape transportation is stopped at the time when the reproducing operation is finished.
Then, the VTR remains in the still reproducing mode. The VTR may again be put into the recording mode with operation of the recording button 65 of the recording operation control part 64. Alternatively, when a STOP REC button 96 of the reproducing operation control part 94 has been pushed, the VTR
is automatically put into the xecording mode. In that case, -~7-~.~.3~
next desired scene to be recorded is never passed over.
Accordin~ to this invention, relative returning move-ment of a recording head and a recording medium to the top of the recorded scene can be certainly and rapidly performed.
Though, in the above embodiment, each of the tapes in both VTRs is driven every other field, this invention may be applied to a device in which each of the tapes is driven every - other frame. In that case, one frame signal should be recorded either as one track on the tape by one recording head, or as a pair of adjacent tracks by two recording heads which ~scan the tape simultaneously but record each track alternatively.
It will be apparent to those skilled in the art that many modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.
.,.
., :
an input terminal A of a selector 84. A control signal is :~ supplied to a control terminal K of the selector 84 from the processing circuit 53 after the start switch 81 is operated.
With the control signal, the input terminal A is selected in .
the selector 84. Accordingly, in the start mode, the output of the VITC signal generating circuit 74 is supplied to another input of the comparator 8~ through the selector 84. Thus, after the selected period of 30 seconds has passed since the point of time when the start switch 81 is pushed, the time code of the output of the VITC signal generating circuit 74 coincides with the time code of the content in the memory 32. As a result, a coincidence signal is supplied from the comparator 83 to the processing circuit 53, which produces a capstan control signal b to stop the capstan motor 36. Thus, the transport of the tape 11 stops and the recording operation is finished.
Thus, only one cycle of recording operation for the time period designated by the interval selection circuit 51 is performed after the start switch 81 is operatcd. Accordingly, there is no trouble of missing the desired recording scene through careLessness. Further, since the top of the recorded scene is found out at the time when the recording operation is finished, the VTR may immediately start the reproducing operation from the top of the recorded scene.
The output of the VITC signal generating circuit 74 is supplied to a display unit 85. The display unit 85 consists of, for example, plural display elements, for example, light emitting diodes, arranged in a line. These elements light in order to form a bar-graph-like display in accordance with change of the VITC signal. The whole lighting (full scale) of the display unit 85 corresponds to the period designated : ~13~32 ` :-through the interval selection circuit 51. Therefore, by monitoring the display unit 85 for the scene to be recorded, - the start switch 81 may be operated again to secure another one cycle of the recording period when the desired scene to be recorded seems to become longer.
:
Search Mode When a stop switch 89 is pushed within the selected recording period (30 seconds, for example) in the start mode, ` the VTR is put into a search mode for finding out the record track identified by the time code corresponding to the time when the start switch 81 is operated. When the stop switch 89 is pushed, the time code at the point of time, that is, the output of the VITC signal generating circuit 74, is supplied to the processing circuit 53 through the stop switch 89, and is memorized in a memory in the processing circuit 53.
The recording operation of the VTR is stopped with the control of the processin~ circuit 53 at the time when the stop switch ;~ 89 is operated. In the processin~ circuit 53, there is per-formed a calculation of the distance between the start track and the stop track on the magnetic tape on the basis of the content of the memory memorizinv the time code corresponding ` to the time when the stop switch 89 is operated and the con-tent of the memory 82 memorizing the time code corresponding to the time when the start switch 81 is operated.
Figures 7-A to 7-D and Figures 7-A' to 7-D' show the positional relationships between the start tracks fs and the stop tracks fe. Figures 7-A to 7-D show the cases where the start track is is situated at one of the forward successive - tracks fl, f3, ..... , and Figures 7-A' to 7-D' show the cases when the start track fs is situated at one of the backward ;~ ~13~432 .
successive tracks fn+2 ...... . In the calculation of the distance between the start track fs and the stop track feJ
difference (T) between respective corresponding time codes ts and te~ namely, T = te ~ ts. is calculated.
As a positive result, T is obtained by the calcula-tion in the cases A and A', the magnetic tape is moved for searching in the direction opposite to the direction of the tape transportation to form the successive-tracks containing the start track fs. Namely, in Figure 7-A, the magnetic tape is moved in the backward direction, fs~ fe~ to search the top of the reproducing scene, and in Figure 7-A', the magnetic ta~e is moved in the forward direction, fe~ fs- to search the top of the reproducing scene.
Since the distance T can not be directly calculated in the cases shown in Figures 7-B and 7-B'; the time code te of the stop track fe is exchanged to a time code te' of the track being adjacent to the stop track fe. Namely, in Figure 7-B, the time code te is exchanged to the corresponding time code of the adjacent forward successive track fe' and in Figure 7-B', the time code te is exchanged to the correspond-ing time code of the adjacent backward successive-track fel, and then, distance T between fs and fe' is calculated. The exchange of the time code may be performed through an encoder which exchange the code between the forward successive tracks and the backward successive tracks. The code exchange may be carried out in response to the detection of turning of the tape transportation. As a positive result, T is obtained by the calculation : T = te' - ts, the tape ls moved for searching in the backward direction fs~ fe as in Figure 7-B, or in the forward direction fe~ fs as in Figure 7-B', in the ~39!43~
same manner as Figures 7-A or 7_~1.
Si~ilarly, in the cases of Figures 7-C and 7-C', the time code of the stop track fe is exchanged to that of the adjacent successive track on the start side, and then, the ; distance T is calculated. Since the difference T shows a negative value, the tape is moved in the forward direction fe~ fs in the case C and in the bac~ward direction fs~ fe in the case c", that is, in opposite direction to the cases A, A' and B, B'.
In the cases of Figures 7-D and 7-D', since the direction of direction of tape transportation is turned twice, the exchange of the time code o~ the stop track fe is not required. The exchange of time code may be carried out only when the turning of the direction of tape transportation is once effected. The distance T = te ~ ts is directly calculated in the cases D and D'. The distance T shows a negative value in each case, and so the tape is moved for searching in the direction fe~ fs in the case D, and in the direction fs~ fe in the case D', in the opposite manner to the cases A and A'.
Thus, the tape feed direction for the searchin~ is determined in accordance with negative or positive sign of the distance T and the number of turnings of the tape transporta-tion. Further, the tape feed speed is determined in accordance with the value of calculated distance T in the processing circuit 53. For example, as shown in Figure 8, when the distance T shows more than 100 frames, the tape is continuously fed at a first feed speed Vs until the distance becomes less than 100 frames. Then, the tape is continuously fed at a second feed speed Vf until the difference becomes less than lq frames.
After that, the tape is intermittently transported for searching :'' .
~ ~ 3~3~
the top of the reproducing scene during the 10 frames.
- In that search mode, the reproduced CTL signals are subtracted one by one from the calculated distance T to detect the positions being of 100 frames and 10 frames far from the start track fs~ when the tape is fed at the first feed speed Vs and the second feed speed Vf. After the result of sub-traction becomes less than 10 frames, the tape is intermittently transported and each stop position of the tape is controlled with servo control to the capstan motor 36 on the basis of the reproduced CTL signal f. In this case, the CTL signal on the CTL track for the successive-tracks opposite to the start track fs is used. Therefore, for example, when the start track fs is included in the forward successive tracks, a reproducing signal obtained from the backward CTL track CTL (B~J) i is used for the servo control. Though there is some mis-tracking at the time when the tape feeding condition is changed to the intermittent transportation from the continuous feeding, an accurate tracking is achieved through the capstan servo control, so that the VITC signal can be detected by the tracking.
In Figure 3, when the VTR is put into the search mode by operating the stop switch 89, a B input is selected in the selector 84 by a control signal from the processing circuit 53. Therefore, the VITC signal detected through the VITC
signal detecting circuit 80 is supplied to the comparator 83 through the selector 84. To another input of the comparator 83, the VITC signal of the start track memorized in the memory 82 is supplied. The top of the recorded scene can be found out by detecting the coincidence of the VITC signal and the content of the memory 82 with each other. The output of the 113~43Z
comparator 83 is supplied to the processing circuit 53, which generates a capstan control signal b to stop the intermittent transportation of the capstan motor 36.
(3), Reproducing Mode The VT~ may be put into a reproducing mode after the search mode is finished. The reproducing mode is automatically obtained after the top of the recorded scene has been found out through the search mode. Alternatively, the VTR may be put into a stop mode after the finish of the search mode, and the VTR may be put into the reproducing mode with operation of a reproducing button (not shown). In the reproducing mode, the change over switch 72 is switched to PB position. Accord-ingly, a reproduced signal obtained from the magnetic head 31 is led out from an output terminal 91 through the switching circuit 69, the change-over switch 72, the reproducing ampli-fier 79 and a selector 90. The selector 90 is provided to change over alternately the reproduced signals from the VTR
part I and VTR part II at every field. The selector 90 is controlled by a change-over signal formed on the basis of the output PG of the pulse generator for detecting the rotational position of the drum motor 55.
Tape runnin~ speed in the reproduction is selected through a tape speed selection control part 92. The output of the control part 92 is supplied to the processing circuit 53, which generates a capstan control signal b to determine . the period of the intermittent drive of the capstan motor 36.
- The slow reproduction mode, the still reproduction mode and the i normal reproduction mode are selected by operating the tape speed selection control part 92. In these reproduction modes, the reproduced VITC signal is supplied from the VITC signal ~ ' ~3~3;Z
detecting circuit 80 to the display unit 85 which has plural display elements arranged in a line to form a bar-graph-like display such as used in the recording operation. The scanning position of the record tracks can be recognized by light-out of the display elements in order in accordance with change of the VITC signal. Further, the VITC signal is supplied to a time display part 93 through the processing circuit 53 to display the frame number of the reproducing track.
In the reproducing mode, each stopping position of the intermittent transportation of the tape is controlled on ~;, the basis of CTL signal recorded in the code recording mode to trace the record track for reproduction of the recorded signal. The reproduced VITC signal from the VITC signal detecting circuit ~0 is supplied to the processing circuit 53 to be compared with the VITC signal memorized in the pro-cessing circuit 53, that is, the time code of the stop track fe at the point of time when the stop switch 89 is pushed.
When the reproduced VITC signal coincides with the memorized VITC signal, the reproduction for the desired scene is over, and next operation is performed in accordance with operation of a reproducing operation control part 94.
When a stop button 95 of the reproducing operation control part 94 has been pushed, the tape transportation is stopped at the time when the reproducing operation is finished.
Then, the VTR remains in the still reproducing mode. The VTR may again be put into the recording mode with operation of the recording button 65 of the recording operation control part 64. Alternatively, when a STOP REC button 96 of the reproducing operation control part 94 has been pushed, the VTR
is automatically put into the xecording mode. In that case, -~7-~.~.3~
next desired scene to be recorded is never passed over.
Accordin~ to this invention, relative returning move-ment of a recording head and a recording medium to the top of the recorded scene can be certainly and rapidly performed.
Though, in the above embodiment, each of the tapes in both VTRs is driven every other field, this invention may be applied to a device in which each of the tapes is driven every - other frame. In that case, one frame signal should be recorded either as one track on the tape by one recording head, or as a pair of adjacent tracks by two recording heads which ~scan the tape simultaneously but record each track alternatively.
It will be apparent to those skilled in the art that many modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.
.,.
., :
Claims (4)
1. A magnetic recording and repro-ducing device comprising two video tape recording and reproduc-ing parts, each having a tape running system including a supply reel, a rotatable head drum assembly, a tape drive wheel, a take-up reel, a capstan for moving said tape in either longitu-dinal direction of said tape, a pair of accumulators between said first tape running system and said second tape running system, said accumulators being constructed to temporarily store and handle varying amounts of tape resulting from the intermittent advance of said tapes, a control head in the tape path of each of said tapes over which at least one marginal edge of each of said tapes rides, each of said control heads having upper and lower recording/reproducing portions which are opposite to the upper and lower portions of their respective associated tapes, means for recording a VITC signal and a color bar on each of said tapes, means for transporting said tapes backward and forward in a selected time interval, said video tape recording and reproducing parts being alternately operated every one field of video signal, said tape control system using an address signal inserted in the video signal and control track signals so as to transport the tape rapidly and accurately to a predetermined position.
2. A magnetic recording and repro-ducing device comprising two video tape recording and reproduc-ing parts, each having a tape running system including a supply reel, a rotatable head drum assembly, a tape drive wheel, a take-up reel, a capstan for moving said tape in either longitudinal direction of said tape, a control head in the tape path of each of said tapes over which at least one marginal edge of each of said tapes rides, each of said control heads having upper and lower recording/reproducing portions which are opposite to the upper and lower portions of their respective associated tapes, means for recording a VITC signal and a color bar on each of said tapes, means for transporting said tapes backward and forward in a selected time interval, said video tape recording and reproducing parts being alternately operated every one field of video signal, said tape control system using an address signal inserted in a video signal and control track signals so as to transport the tape rapidly and accurately to a predeter-mined position.
3. A magnetic recording and repro-ducing device comprising means for intermittently transporting a magnetic recording and reproducing head over which said medium passes, means for moving said medium in forward and backward directions over said head for forming record tracks on said magnetic medium on which a video signal is recorded and from which said video signal is reproduced, said device com-prising an address identification code recording and reproducing means to record and reproduce an identification code on and form a part of each said record track with said video signal for identifying each of said record track, a memory means for memorizing said identification code in accordance with operation of a first operating means, said identification code being of a code at a point of time when said first operating means is operated, a distance detecting means to detect a relative movement between said recording head and said recording medium in accordance with operation of a second operating means operated in the recording operation, on the basis of another identification code at a point of time when said second operating means is operated and the identification code memorized in said memory means, a returning movement control means to control relative returning movement of said recording medium, to the position identified by the code at the time when the first operating means is operated, in accordance with the output of said dis-tance detecting means, said relative returning movement being carried out at a predetermined speed and then by intermittent movement when the relative distance reaches a predetermined value, and a coincidence detecting means to detect the coinci-dence of a reproduced identification code obtained from said identification code recording and reproducing means, with the identification code memorized in said memory means, during said intermittent returning movement, and to supply a returning movement stop signal to said returning movement control means.
4. A magnetic recording and repro-ducint device comprising a tape running system including a supply reel, a rotatable head drum assembly, a tape drive wheel, a take-up reel, a capstan for moving said tape in either longitudinal direction of said tape, an accumulator in said tape running system on each side of said capstan, said accumulator being constructed to temporarily store and handle varying amounts of tape resulting from the intermittent advance of said tape, a control head in the tape path of said tape over which at least one marginal edge of said tape rides, said control head having upper and lower recording/reproducing portions which are opposite to the upper and lower portions of its associated tape, means for recording a VITC signal and a color bar on said tapes, means for transporting said tape backward and forward in a selected time interval, said video tape recording and reproduc-ing device being alternately operated every one field of video signal, said tape control system using an address signal inserted in the video signal and control track signals so as to transport the tape rapidly and accurately to a predetermined position.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4162078A JPS54133820A (en) | 1978-04-08 | 1978-04-08 | Recording regenerator for video signal |
| JP41620/78 | 1978-04-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1139432A true CA1139432A (en) | 1983-01-11 |
Family
ID=12613373
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000324841A Expired CA1139432A (en) | 1978-04-08 | 1979-04-03 | Magnetic recording and reproducing device |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS54133820A (en) |
| CA (1) | CA1139432A (en) |
| DE (1) | DE2914020A1 (en) |
| FR (1) | FR2423840B1 (en) |
| GB (1) | GB2018465B (en) |
| NL (1) | NL7902697A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5989084A (en) * | 1982-11-12 | 1984-05-23 | Sony Corp | Video tape |
| US4734792A (en) * | 1984-07-24 | 1988-03-29 | Ricoh Company, Ltd. | Record address data recording apparatus for use with a VTR or the like |
| JPH0454014U (en) * | 1990-09-07 | 1992-05-08 |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2055538A1 (en) * | 1969-12-24 | 1971-07-01 | Ibm | Arrangement for finding information recorded on magnetic tape |
| US3681523A (en) * | 1970-08-13 | 1972-08-01 | Ampex | Transport controller |
| GB1425321A (en) * | 1972-05-09 | 1976-02-18 | Selectro Micro Co Ltd | Information retrieval apparatus |
| US3839731A (en) * | 1972-12-01 | 1974-10-01 | Ibm | Apparatus for sensing relative position behind head and track in transverse magnetic recording without a separate control track |
| JPS5949754B2 (en) * | 1976-07-31 | 1984-12-04 | ソニー株式会社 | tape editing machine |
-
1978
- 1978-04-08 JP JP4162078A patent/JPS54133820A/en active Pending
-
1979
- 1979-04-03 CA CA000324841A patent/CA1139432A/en not_active Expired
- 1979-04-05 NL NL7902697A patent/NL7902697A/en not_active Application Discontinuation
- 1979-04-06 DE DE19792914020 patent/DE2914020A1/en not_active Withdrawn
- 1979-04-06 GB GB7912123A patent/GB2018465B/en not_active Expired
- 1979-04-09 FR FR7908976A patent/FR2423840B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| NL7902697A (en) | 1979-10-10 |
| JPS54133820A (en) | 1979-10-17 |
| FR2423840A1 (en) | 1979-11-16 |
| FR2423840B1 (en) | 1986-11-14 |
| GB2018465A (en) | 1979-10-17 |
| DE2914020A1 (en) | 1979-10-18 |
| GB2018465B (en) | 1982-07-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |