JPS5998305A - Video tape recorder - Google Patents

Abstract

PURPOSE:To execute exactly an access of a recording program by providing a fixed head in a gap direction having an angle against the gap direction of a video head on a recording face, in accordance with a range in which a vertical retrace line part of a video track is positioned, and recording and reproducing an address information by this fixed head. CONSTITUTION:As for a tape T, an audio track AT in which an audio signal is recorded and a control track CT in which a control signal for a tracking control at the time of reproduction is recorded are formed along a running direction RD of the tape T on both side edge parts, respectively, and between them, many video tracks VT which have an inclined angle of theta deg. against the running direction RD and are in parallel to each other are formed. As for this track VT, recording is executed by two video heads VH1, VH2 having azimuth angles of -alpha deg. and +alpha deg., respectively, in the direction meeting at a right angle with a video track direction VD.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a video tape recorder (hereinafter referred to as "VTRJ") that employs a rotating head helical scan method for recording/reproducing video signals, and particularly relates to a video tape recorder (hereinafter referred to as "VTRJ") that employs a rotating head helical scan method for recording/reproducing video signals, and particularly relates to a recording program. This relates to a recording/reproducing method of address information for access.

[Technical background of the invention]

In the case of a general-use VTR 1, such as a home-use cassette-type VTR, that does not have a dedicated track for accessing the recording recorder,
In order to search for a recorded portion with desired content during playback, it is common to search while looking at the screen in a so-called search mode in which the chip feed speed is increased, for example, by 3 to 4 times.

However, in this case, there are problems in that noise particles occur on the screen, making it difficult to distinguish the desired location, and that attempting to reduce the influence of noise particles to some extent results in a significantly complicated configuration. Furthermore, in this case, the search speed cannot generally be made very high, so the desired recorded record cannot be found in a short period of time unless the user alternates with a fast-forward operation (the screen does not appear). For this reason, the operation of υ-1 was complicated, and it ended up taking a considerable amount of time.

In particular, recently, VTRs and tapes have become available that have a recording mode that allows up to 8 hours to be recorded on a single cassette videotape, making it difficult to find the beginning of a desired program when multiple programs are recorded. I'm on my way.

In order to make program searches and the like as easy as possible, the following methods have been considered.

(b) Compare the indicated value of the tape counter with the number assigned to the program, and record information indicating the correspondence between the above-mentioned tape counter indicated value and the program number in a catalog area set in advance at the beginning of the tape. At the time of playback, this is referred to and a desired program is searched based on the tape counter indication value.

←) During recording, a predetermined low frequency signal is recorded immediately before each program, and during playback, this low frequency signal block is detected to search for a desired program.

Here, the above method ←) will be explained in detail by taking as an example.

In Figure 1, 1 is a rotary head cylinder, 2 is a cab stun, 3 is a pinch roller, 4 is an erasing head, 5 is a detection head, 6 is a supply side reel, 7 is a winding side reel, 8 is a beginning A signal recording circuit, 9 a counter, 10 a comparator, and 1 a reel motor control circuit. During recording, a low-frequency cue signal of, for example, 30 Hz generated by the cue signal recording circuit 8 is programmed (first
For example, the data is recorded for about 1 second at the beginning of the first section (th). Then, the first video program is recorded by a recording head (not shown) provided in the rotary head cylinder 1. Next, when recording the second video program, the 30 Hz cue signal is recorded again in the immediately preceding portion of the program in the same manner as described above, and then the second video program is recorded. When recording the third and subsequent video programs, a 30 Hz cue signal is recorded for about 1 second in the immediately preceding portion of each program in the same manner as described above. Then, in the search operation, the number of the program to be selected (a number indicating the program number) is set in the comparator 10 in advance, and when the search operation is started, the tape 0T returns to the beginning and the counter 9 is set. Chi 7″ after zero reset
T starts fast and opens to begin searching for the selected R location. The counter 9 counts the number of times the cue signal is detected by the detection head 5, and when this count value matches the set zologram number, it is detected by the comparator 10, and this output is used to control the reel motor control circuit. When NO is activated, the reel motor is stopped and high-speed tape feeding is temporarily stopped, and then the normal playback mode is automatically entered. In this way, the setting program can be searched and reproduced.

With this method, it is easy to generate and record a cue signal, but since the count value of the cue signal is used, the actual program position and the above count value may no longer correspond due to cassette replacement, etc. There is a problem that the correct program position cannot be determined unless the tape is rewound to the beginning and the counter 0 is reset each time. There are still problems, such as a part of the tape becoming unusable for recording video information because of the recording of cue signals, and the inability to search for intermediate positions in the program.

All of these problems are caused by the fact that there is no absolute address corresponding to the program on the tape, and the same problem remains in the case of (a) above.

It has been said that it is not easy to improve this problem because home cassette type VTRs do not have a track for accessing a nologram, such as the key track in a commercial office VTR.

[Purpose of the invention]

The present invention enables absolute address information of recorded zolograms to be used without adversely affecting the recording/playback of video tracks even if a recording format in which a dedicated track for access by a recording program is not originally provided independently is used. The object of the present invention is to provide a VTR that enables recording/reproduction of data and accessing recorded programs easily and reliably.

[Summary of the invention]

In the present invention, it corresponds to the range where the vertical blanking portion of the video track is located on the magnetic recording surface,
The present invention is characterized in that a fixed head is provided whose gap direction is at an angle to the gap direction of the video head on the same recording surface, and the fixed head records/reproduces address information. That is, in the present invention, a cue track for recording address information is formed by superimposing it on a vertical retrace portion of the video track that has relatively little influence on the reproduced image, and recording/reproduction of this key track is performed by a rotating video head. A fixed head with sufficient azimuth should be used for this purpose.

[Embodiments of the invention]

FIG. 2 shows a recording format on a tape in an embodiment of the present invention, and FIG. 3 shows a schematic configuration of the main parts of the embodiment.

In FIG. 2, an audio track AT on which an audio signal is recorded and a control track CT on which a control signal for tracking control during playback is recorded are located on the edge of the picture side in the running direction RD of the tape T. θ0 (for example, 5°58'9.9") with respect to the traveling direction RD.
.

An angle of inclination (such as 5°00'51', which varies depending on the method)
A large number of video tracks VT are formed parallel to each other with a video track angle).

This video track VT has two video heads (in the figure (only the gap portion is schematically shown) VHl and VH2 (mounted at 180° different positions on the rotary head cylinder 1). These are common to conventional household cassette type VTRs.

In this embodiment, the video track VT is further overlapped within a range corresponding to the vertical f ranking section portion (the portion near the control track CT of each trough) of the video track VT in the running direction RD of the tape T. An address track ADT is set along the video track direction VD, and recording/reproduction of this address track ADT is performed using a fixed (
Addressing head consisting of a non-rotating (non-rotating) head (only the dark and narrow portion is schematically shown) ADH is used. Therefore, this address head ADH has a large azimuth angle with respect to the video head Vl'll e VH2, and the influence of mutual crosstalk during recording/reproduction is extremely reduced. Here, address head ADH
The gap direction of V is not necessarily strictly the video track direction V
D and the video track VT do not have to be long.
q, it is sufficient to form an azimuth that sufficiently reduces the influence of the stalk.

In FIG. 3, a rotating head cylinder 1, a supply reel 6
, take-up reel 7, video head VH2, and address head ADH correspond to the parts with the same reference numerals already explained in FIGS. 1 and 2. CH is a control head 1 for recording and reproducing the control track CT. sw,” SWs
C) A changeover switch for switching between recording mode and search mode. 21 is a position detector that detects the rotational position of the cylinder 1 using a magnet (not shown) provided on the rotary head cylinder 1;
outputs pulses (every half revolution). 22 is a flip-flop that divides the output of the position detector 21 by μ; 23 is an input terminal 9 to which the vertical synchronizing signal VD extracted from the input video signal is input; 24 is the output of the rotational position detector 2 of cylinder l and a switch 25 is a cylinder motor that rotationally drives the cylinder 1; 26 is a cylinder drive control that controls the speed of the cylinder motor 25 and drives it according to the output of the phase comparison circuit 24; 27 is an input terminal into which an address control signal for address signal recording is input; 28 is an address generator that outputs a recording address signal in synchronization with the output of the flip-flora f22 in response to the address control signal; 29 is an Input terminal 3 to which search address setting input is given at the time of search
0 is a comparison circuit that compares the address information reproduced by the address head ADH and the search address setting input input from the input terminal 29 and outputs a match detection signal when they match; 3 is a reel motor for driving the supply reel; , 32 is a reel motor for driving the take-up reel, 33 is an input terminal to which a search operation start command is given, and 34 is a match output terminal that drives the reel motors 31 and 32 in response to the start command, and is output from the comparison circuit 30. This is a reel motor control circuit that stops the reel motors 31 and 32 in response to a detection signal.

Next, the operation in the configuration as shown below will be explained in detail.

(a) When recording; (a) When recording the first zologram, set the changeover switches SW, ~sw3 to the R side to set the recording mode,
Tape T is removed by operating the canostan mechanism (not shown).
The vehicle is driven in the direction RD shown in the figure.

←) At the same time, the rotary head cylinder 1 rotates, and the video head VH1 fixed to the cylinder 1 is attached to the tape T wound diagonally over half the circumference of the rotary cylinder 1.
r Record the video signal of the first videonologram by VH2. This recording is performed for two tracks (one frame) per revolution of the cylinder 1.

(c) The rotation of the cylinder 1 is detected by a position detector 21 consisting of a magnetic detector fixedly arranged in correspondence with two magnets sorbed at 180° different positions on the cylinder 1. -2.9 Lus per revolution
output as a pulse sequence.

b) The pulse train obtained by the position detector 21 is given to the phase comparator circuit 24 and used to control the rotation of the cylinder 10, and is frequency-divided by A by the 7'70' 22. The output of this flip-frog 22 is the video head vH1,
In addition to being used as a switching signal for vH2 (the switching system is not shown in Figure 1), it is also applied to the address generator 28 and used as synchronization information for address signal recording, and is further applied to the control head CI via switch SW3. The control output is recorded on the control track CT of the tape T.

By the way, during recording, the rotation of the cylinder 1 must be synchronized at a rate of one rotation for every two cycles of the vertical synchronization signal VD of the input video signal. Therefore, the phase comparison circuit 24 compares the phases of the vertical synchronization signal VD separated and generated from the input video signal, that is, the input of the input terminal 23 and the output of the rotational position detector 21, and according to the comparison result, the synchronous rotation The cylinder motor 25 is driven by controlling the drive control circuit 26 so as to cause the cylinder motor 25 to move.

(v) On the other hand, address signal recording is performed by applying an address control signal to the address generator 28, which is supplied with the pulse output of the 7Rhinoflop 22 as a synchronization signal for address signal recording.
One word of address code per rotation of the address generator.

28 and recorded on tape T in the format described above. In this case, the same address code is repeatedly recorded during the same program.

Therefore, as shown in FIG.
When H and one control head CH are arranged so that their positions in the tape running direction RD coincide with each other, the video track VTI r V as shown in FIG.
The recording positions of the address codes ACI eAc2 #... corresponding to Tz r VT3 p... are the video tracks VTI e VTz * v'r, respectively.

...pair control pulse CPI + CPz
apl-CP of each recording position of ycp3,...
The positions correspond to CP2-023, . . .

In addition, control Yarus CP1 g CP2 t.
The recording position of ... is each corresponding video track VTI p
From the terminal position of VTz g...
244 network, 6B, OWA, etc. (depending on the system).

The relationship between the recording timings of the address codes AC1r AC2*, . . . and the control pulses CPI HCPz, . . . is shown in FIG. In addition, the address codes Act, AC2+... are from MBS (most significant bit) to LSB (least significant bit) as shown in the figure.
In the figure, each address code ACI + AC2+ is recorded as 5-bit data in the order shown in the figure, and each address code ACI + AC2 + is recorded after each control and address CP1 * CPz * ... of the corresponding video track v'rll v'r, l...・
... is recorded. This means that the synchronization number M and the I, -c control pulses CPt for reading the address code ACI + AC2p... during the search described later.
This has the advantage that reading can be easily performed without using a PLL (Phase Lock Luso) or the like having a wide lock range.

For example, if one tape roll contains 30 programs, the address code ACI r AC2s... is 5 bits (
Data for a maximum of 32 types is sufficient, and 8 bits is sufficient even considering the margin. This address code Act
+AC2, . . . will record addresses 30 times per second, so for example, if it is 8-bit data, the bit repetition frequency will be about 240 Hz.

(g) When recording the second program, after recording the first program, the output pulse of the flip-flop 22 is given a 4' period, and the previous address is then recorded. For example, record an address code larger by 1 in 7 address heads ADH.

(b) Thereafter, record multiple nologograms in the same manner.

(b) When searching; (a) When searching, set the switches SW and ~sw3 to the S side to enter the search mode, and input the address value attached to the program to be searched from the input terminal 8 terminal 29 to the comparison circuit 3.
Enter the setting to 0.

(b) By giving a search start command to the reel motor control circuit 34 from the input terminal 23, the tape T is first driven in the forward direction by the operation of the reel motors 31 and 32, and the address code of that location is sent from the address head AI)H. is detected.

(c) The address code detected by the address head ADH is input to the comparison circuit 30, where it is compared with the set address value determined by the setting input from the input terminal 29.

The reel motor control circuit 34 is controlled according to the result of this comparison, and the tape T is driven at high speed via the reel motors 31 and 32. That is, if the set address (i6) is thicker, the tape T is driven directly in the IIIN direction, and if the set address value is smaller, the tape T is reversed in direction and driven in the opposite direction.

) When a match is detected in the comparator circuit 30, the reel motors 31 and 32 are temporarily stopped via the reel motor control circuit 34 based on the output of the comparator circuit 30, and then switched to the normal reproduction mode.

Therefore, playback is performed from the beginning position (i) of the program corresponding to the specified address. At this time, in the case of reverse rotation, the upper and lower order of the address code is reversed from the forward direction, so the comparison is performed accordingly. Also, since the position where the scattered output is produced is the end position of the desired program, the normal playback mode is entered when the program returns to the beginning position of the program or the end position of the next program.

? When comparing the address codes in (c) above, by giving the reproduction control pulse pulse obtained by the control head CH to the comparison circuit 30 and using it as a synchronization signal, it is possible to easily perform a PLL with a wide lock range.
It is K if the address code can be read without using etc.

In this way, absolute address information can be recorded over the entire area in the program recording area, and this can be reproduced and detected in a high-speed transmission state, so that access to the program can be easily performed in a short period of time. Moreover, since address information is recorded superimposed on the video track VT section, it maintains compatibility with conventional recording formats that do not have an address track, while providing the same functionality as having a separate track for address information. can be obtained.

Furthermore, the address information is stored in the vertical flyback section of the video track VT that has the least effect on the image.

The crosstalk is sufficiently reduced by the azimuth.
There is also the advantage that there is almost no adverse effect on the video screen since it is carried out in such a way that the video screen is not affected.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without changing the gist thereof.

For example, by recording/reproducing local addresses in units of one frame or multiple frames instead of addresses for each program, it becomes possible to search any location on the entire tape T. Additionally, this local address may be used in combination with a program address. Alternatively, an arbitrary address may be recorded in an arbitrary number 71r so that it can be searched. These are useful for partial repeat playback, editing, etc.

Further, the position of the address head A4)H does not necessarily have to coincide with the position of the control head CH, and may be set to a suitable position as appropriate.

Furthermore, instead of using the control/4' pulse from the control head CH as it is as a synchronization signal for the address code synchronized with the rotation of cylinder 1, the address head ADH is designed to record and reproduce both the synchronization signal and the address code. You can. In this case, separation detection can be easily performed by recording in a waveform in which the polarity of the reproduction output of the address head ADH differs between the synchronization signal and the address code. Although the case of recording video recording has been described so far, the same applies to the case of recording audio PCM information in a video format, for example.

〔Effect of the invention〕

According to the present invention, it is possible to record/reproduce absolute address information of a recording program without independently providing a dedicated track for accessing the recording program on the tape surface, and it is possible to easily access the recording program. It is possible to provide a VTR that can perform this operation reliably and that does not adversely affect recording/reproduction of video tracks.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining an example of a conventional method, Fig. 2 is a diagram for explaining a recording format in an embodiment of the present invention, and Fig. 3 shows a schematic configuration of the main parts of the embodiment. 4 are waveform diagrams for explaining the same embodiment. VH,, VH2...Video head, ADH...Address head, CH...Control head, SWl"
”-8W3...Selector switch, 1...Rotating head cylinder, 6...Supply reel, 7...Take-up reel, 2
1...Position detector, 22...Flip frog, 2
3... Vertical synchronization signal input terminal, 24... Phase comparison circuit, 25... Cylinder motor, 26... Drive control circuit, 27... Address control signal input terminal, 28...
Address generator, 29...Search address setting input terminal, 30...Comparison circuit, 31.32...Reel motor, 33...Search start command input terminal, 34...Reel motor control circuit.

Claims (1)

[Claims] Video signal recording/recording using rotating head edge scan method
In a video tape recorder that performs playback, the magnetic tape is arranged within the range where the vertical retrace line portion of the video track is located on the recording surface of the magnetic theno, and is angled with respect to the gap direction of the video head on the same recording surface. 1. A video tape recorder characterized in that a fixed head is provided in the gap direction, and address information is recorded/reproduced by the fixed head.