JPH02116278A - Video signal recording device - Google Patents

Abstract

PURPOSE:To shorten the tracking control lead-in time of a recording/reproducing system using plural heads by recording a tracking control signal at an (n) track cycle by a device which forms tracks in an (m) number (m>n) per one frame on a recording medium by rotary heads in an (n) number (n>2). CONSTITUTION:The title device records a video signal while forming the tracks in the (m) number per one frame (integer of m>n) by the rotary heads in the (n) number (n is integer at >=2), and records the tracking control signal at the (n) tracking cycle. Thus, since tracking lead-in points exist at every (n) tracks, the tracking control lead-in time is shortened, and when the reproduction is executed by the same devices, the recording head and reproducing head are made into the same head, and excellent recording/reproducing characteristic can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a video signal recording device, and more particularly to a video signal recording device using a plurality of rotating heads.

[Prior Art] Rotating head type video tape recorders have become popular as consumer equipment. This rotating head type video tape recorder (VTR) records and reproduces video signals while forming diagonal tracks on a magnetic tape, which is a recording medium. Additionally, in order to increase recording density, no guard band is provided between adjacent tracks, and crosstalk from adjacent tracks during playback is reduced by azimuth loss caused by varying the azimuth angle of the recording/playback head between adjacent tracks. .

In such a VTR, it is necessary for the playback head to accurately trace the tracks recorded on the magnetic tape.
The tracking control that controls this plays an important role.

Conventionally, in devices that perform high-density recording and playback such as digital video recorders, so-called area division ATF (Automatic Tracking) is used for tracking control.
(Finding) method is used. This method is called DAT (Digital Audio Tape).
This is a tracking method typified by a tracking system (recorder), in which a pilot signal is recorded in a tracking control area provided on each track separately from the main information data.

In this system, conventionally, the number of repeated tracks of the recording pattern of the pilot signal on the magnetic tape is equal to the number m of tracks required to record one frame of a signal to be recorded, for example, a video signal.

Hereinafter, recording and reproduction in the case where m=1=6 and the number of heads n is 4 will be specifically explained using FIG. FIG. 6 is a diagram showing a recording pattern on a tape. In the figure, 1 is a magnetic tape as a recording medium, and 2 is a recording track recorded on the magnetic tape l. Since the period of the recording pattern of the ATF pilot signal is equal to the number of tracks required to record one frame of the video signal, the recording pattern as shown in FIG. 6 is obtained. In addition, Data in the figure is a video signal, ATFI
~ATF6 indicates a one-cycle ATF pilot signal.

When attempting to reproduce such a recording pattern, a servo pull-in point will exist for each period of the recording pattern of the ATF pilot signal if tracking is performed using the tape transport system. In this case, since m = 41 = 6, there is a pull-in point every 6 tracks. That is, since conventionally m = 1, the number of tracks required to record one frame of the video signal becomes the pull-in point of the tape feed servo system.

[Problem to be solved by the invention] However, when recording a signal with a very large amount of information such as a high-definition television signal, the number of tracks required to record one frame of video signal increases, and the tape feed servo It takes a long time for the system to reach the servo pull-in state. It is also assumed that recording pattern 2 in FIG. 6 is recorded and reproduced using four heads. At this time, even when recording and reproducing are performed using the same device, there may be a case where the head for recording and the head for reproducing the respective tracks of the recording track 2 are not the same. This is because the number of repetitive tracks and the number of heads of the ATF pilot signal are different. If the recording and reproducing heads are not the same, even in recording and reproducing using the same device (self-recording and reproducing), which should have optimal characteristics, variations in the characteristics of the heads will cause instability.

[Problems to be solved by the invention] That is, the conventional system has the following two problems.

That is, (1) when recording and reproducing a signal with a very large amount of information such as a high-quality image, the tracking servo pull-in time becomes long.

(2) Even during self-recording and reproducing, the recording and reproducing heads are not the same head, and optimum characteristics cannot be obtained due to head variations.

In view of the above-mentioned problems, the present invention provides a video signal recording device that can shorten the tracking control pull-in time and realize good recording and reproducing characteristics in a recording and reproducing system that records signals with a large amount of information such as high-quality images. The purpose is to provide.

[Means for Solving the Problems] To achieve this objective, the present invention has n (n is an integer of 2 or more) rotating heads and m (m is an integer greater than n) per frame. This apparatus records a video signal while forming tracks on a recording medium, and is configured to record a tracking control signal at a cycle of n tracks.

[Function] By configuring as described above, a tracking pull-in point exists every n tracks, so the tracking control pull-in time becomes shorter than before, and if playback is performed with the same device, the recording head and the playback head are Since the heads are the same, good recording and reproducing characteristics can be obtained.

[Example] The present invention will be explained below using examples.

FIG. 1 is a diagram showing a recording pattern by an apparatus according to an embodiment of the present invention, where 1 is a magnetic tape which is a recording medium, and 2 is a recording track recorded on the magnetic tape 1. In FIG. That is,
Figure 1 shows the number of repeating tracks (recording period) of the pilot signal for ATF, and if the number of tracks (m) required to record one frame of the video signal and the number of rotating heads is (n), then 1=
This is an example of a recording pattern on a magnetic tape when n=4 and m=6. By setting l=n, during self-recording/playback, the head that records a certain track and the head that reproduces it can be the same, and this relationship is maintained for all tracks. Due to this stable relationship between the recording and reproducing heads, stable video signal recording and reproducing characteristics and tracking servo characteristics can be obtained.

In addition, in the conventional method, since m is equal to a sentence, m
= 1 = 6, and the cycle of the tracking control pull-in point is (M =) 6) racks, but in the embodiment of the present invention, m
Since it is made equal to n (m=n=) 4) it becomes a rack and the drawing characteristics are improved. The larger the difference between n and the sentence, the greater the improvement effect. Therefore, the present invention is very effective in a recording device that requires many tracks to record a video signal of one frame with a very large amount of information such as a high-quality image.

FIG. 2 is a diagram showing an example of the structure of the head of the apparatus of this embodiment.

In FIG. 2, 3 is a rotating drum, and 4a to 4d are heads mounted on the rotating tram 3. head 4a and head 4
b and shows the case where the heads 4C and 4d are arranged close to each other; in this case, between the heads 4a and 4b, and the head 4C
A step is provided between the head 4d and the head 4d in the direction of the rotation axis.
A and 40 are installed on the same rotating surface. At this time, the tape is fed by two tracks in the time it takes for the rotating drum to rotate 180 degrees, and between heads 4a and 4b, and between heads 4C and 4.
The level difference X between d is 'x=', where Tp is the trigger pitch
It is determined by (TPθ TP×−×2). If 0 is close to 0, then XζT
It becomes p.

FIG. 3 is a block diagram showing the overall general configuration of the apparatus of this embodiment, and FIG. 4 is a timing chart for explaining the operation of the portion shown in FIG.

In the figure, 10 is a terminal to which a video signal to be recorded is input, and the input video signal is supplied to a recording data processing circuit 12 and a vertical synchronization signal (VD) separation circuit 14. The VD separated by the VD separation circuit 14 is supplied to a frame pulse (FP) generator 16, which generates an FP as shown in FIG.
get. The recording data processing circuit 12 processes the video signal at a timing according to this FP. This video signal processing circuit 12 performs sampling, encoding, error correction code, synchronization code, addition of additional code (ID), etc., and outputs six systems of data strings. FIG. 4A schematically shows six output systems from the circuit 12. In the figure, the front numbers 1-1 to 3-6 indicate frame numbers, and the trailing numbers indicate system numbers. As is clear from the figure, the recording data processing circuit 12 has one pulse between each pulse of FP.
Six lines of data including one frame's worth of video data are output. Also, the frame number and system number are recorded in the ID in the data of each system.

Reference numeral 18 denotes six memories that perform time axis compression, and time axis compresses the six systems of data from the recorded data processing circuit 12 to each station in units of one frame period, and the timing shown in FIG. 2B is and output it. The shaded area indicates a period during which no data is transmitted. The read/write timing for these memories 18 is common to each frame, and is controlled by the FP output from the circuit 16.

The six time-axis compressed data from the memory 14 are supplied to the system conversion circuit 20 and converted into four systems. This conversion performs the same processing in a period of 2 frames, so the FP is converted into a pulse (51'
zFP). The four systems of data output from this system conversion circuit 20 are as shown in FIG. 4C, and are sent to adders 24a and 24b, respectively.

24c, 24d, switches 26a, 26b.

Head 4a via the R side of 26c and 26d.

4b, 4c, and 4d.

28 indicates four types of tracking control pilot signals; heads 4a, 4b, 4c, and 4d are ATFI and AT in FIG.
F2. There is an ATF signal generation circuit which supplies the adders 24a, 24b, 24c, and 24d at the timing of tracing the areas indicated by ATF3 and ATF4, and the heads 4a and 4b at the same period as the rotation period of the drum 3.

The generation timing of the ATF pilot signal is determined according to the rotation detection pulse (PG) which is inverted at the timing when the head 4 c and 4 d start tracing the tape l and the timing when the heads 4 c and 4 d start tracing the tape l. here,
The adders 24a, 24b, 24c, and 24d are supplied with four systems of data in which a station frame period containing data and a station frame period not including data are alternately repeated, and immediately before the station frame period containing the above data. An ATF pilot signal is added in a predetermined period immediately thereafter.

The PG generated by the rotation detector 30 is frequency-divided by a local oscillator 32 and supplied to a drum control circuit 34. Further, %FP outputted from the local frequency generator 22 is supplied to the drum control circuit 34 via the R terminal of the switch 36, and is compared in phase with the output of the local frequency generator 32. The drum motor 38 controls the rotation of the drum motor 38 so that the output of the local frequency generator 32 and the output of the local frequency generator 22 coincide in timing.

By configuring as described above, recording can be performed according to the recording format shown in FIG.

Incidentally, during recording, the capstan motor 38 is operated by the capstan control circuit 40 at four speeds during one rotation of the tram 3.
The tape 1 is controlled to be transported track by track.

Next, the operation during playback will be explained. Switches 26a, 26b, 26c during playback.

26d and 36 are all switched to the P side. head 4a,
The outputs of 4b, 4c, and 4d are supplied to an ID separation circuit 42, an ATF processing circuit 44, and a system conversion circuit 46, respectively. 46
is a reference oscillator that generates a reference pulse (RFP) with a period of l frames, and 48 is a local oscillator. % when playing
Divided RFP ()fRFP) and monthly divided PG
The drum control circuit 34 controls the drum motor 38 so that the phases of the drums match.

In this case, if PG has a phase as shown in Fig. 4, %RFP
is relatively %RFP-1゜坏RFP-2. in FIG.坏R
This will be one of the phases of FP-3.

The ATF processing circuit 44 processes the AT in the four regenerated signals.
The F pilot signal is separated according to PG, and a tracking control signal is supplied to the capstan control circuit 40 after performing well-known processing. At this time, this tracking control signal is a signal for controlling the capstan so that each head 4a, 4b, 4c, 4d traces its own recorded track, and according to this, each head 4a, 4b, 4c,
4d outputs reproduced data as shown in FIG. 4C.

The system conversion circuit 46 is a circuit that converts the 4 systems of playback data from each head into the original 6 systems of data, and the distribution to each of the 6 systems is performed using the ID separation circuit 42 based on the system number of the ID in the data of each track. The system number is read according to this system number. Therefore, the output of the system conversion circuit 46 is
It will look like Figure B.

Reference numeral 48 denotes six memories for time-expanding the station frame period of the data of the six systems from the system converting circuit 46 by three times and appropriately delaying the data. The read timing from these memories 48 is determined according to RFP. However, the delay time of each memory is determined according to the frame number in the ID separated by the ID separation circuit 42 so that data of the same frame is read out at the same timing. That is, IRFP is ylRF for reproduced data C shown in FIG. 4C.
In the case of the phase indicated by P-1, Fig. 4 D-1, 114RF
In the case of the phase shown as P-2, Fig. 4 D-29%RFP-
In the case of the phase indicated by 3, data is read from the memory 48 at the timing shown in FIG. 4D-3.

The reproduced data processing circuit 50 performs processing reverse to that during recording, that is, error correction, decoding, analogization, etc., at the timing according to the RFP, and outputs l-system analog video signals from the terminal 52.

According to the digital video table recorder of the embodiment as described above, each head 4a is as described above.

4b, 4c, and 4d reproduce the tracks recorded by themselves, so they can obtain good recording and reproducing characteristics, obtain a good reproduced video signal, and perform accurate tracking control.

FIG. 5 is a diagram showing another example of the head configuration, and in this example, heads 4a, 4b, and 4c are shown.

4d rotate with a phase difference of 906 from each other and rotate on the same rotation plane. The present invention can be similarly applied to such a head configuration. For example, when configuring a device as shown in FIG. 3 with this head configuration, the memory 1
The output timing of system number 8 may be shifted by 1/6 frame period for system numbers 2 and 4.6, and the processing thereafter may be performed at timings that follow this.

In this embodiment, the case where the number of heads n and the number m of recording tracks of a video signal in which the recording pattern of the pilot signal has repeated tracks of 4.1 frames is 6 has been described, but in general, the number m of recording tracks is n-1. It is my theory that a similar effect can be obtained when n<m.

[Effects of the Invention] As described above, according to the present invention, the tracking control pull-in time in a recording/reproducing system using #i heads can be shortened, and the video signal recording can realize good recording/reproducing characteristics. A device is obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a recording pattern by an apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing a head configuration of an apparatus according to an embodiment of the present invention, and FIG. 3 is a diagram showing a recording pattern according to an embodiment of the present invention. Figure 4 is a timing chart for explaining the operation of each part in Figure 3. Figure 5 is a diagram showing a modification of the head configuration. Figure 6 is a recording pattern by a conventional device. FIG. In the figure, 1 is a magnetic tape, 3 is a rotating drum, 4a, 4b, 4
c, 4d are rotary heads, 12 is a recording data processing circuit, 2
8 is an ATF signal generation circuit, 44 is an ATF processing circuit, 4
6 is a system conversion circuit, and 50 is a reproduction data processing circuit.

Claims (2)

[Claims] (1) A device that records a video signal while forming m tracks (m is an integer greater than n) per frame on a recording medium using n rotating heads (n is an integer greater than or equal to n), A video signal recording device that records tracking control signals at n-track cycles. (2) The video signal recording device according to claim (1), wherein data indicating the track number of each frame is recorded in each track.