JPH01269206A - Information recording and reproducing device - Google Patents

Abstract

PURPOSE:To execute reloading and adding without the degradation of information by providing an auxiliary head, which pursues the trace track of a recording and reproducing head after a constant time, and supplying data in a storing means to this head. CONSTITUTION:Only the two signals of an audio signal B and sub-data B to be written to a second area, out of signals from a decoder 16, are stored to a memory which is built in a mixer 20. For adding or reloading the information to be recorded in the second area, an audio signal C is passed through an A/D converter 51 and sub-data C are inputted to the mixer 20 as they are. There, the update of conventional data is executed and the updated data are inputted to an encoder 41. The data are not sent to heads H1-H4. In the encoder 41, an error correcting code is added to an input signal and shuffling is executed. Then, the signal is inputted to a multiplexer 61 and distributed to respective recording amplifiers 71 and 81. The signal to pass through the recording head amplifiers 71 and 91 is respectively recorded to the second area in the same track of a magnetic tape, which is reproduced by the heads H1 and H2, by heads h1 and h2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an information recording and reproducing apparatus such as a digital video tape recorder (hereinafter referred to as digital VTR).

[Prior Art] A digital VTR is capable of digitally encoding analog video/audio signals and recording them on a magnetic tape, and further reproducing the thus recorded signals. FIG. 5 shows an example of the arrangement of heads on a rotating drum in such a digital VTR. 1 is a rotating drum, and ``old'' (i-1 to i-4) indicate heads, respectively.

Further, FIG. 6 shows recording patterns on the tape recorded by the heads H1 to H4. In this example, one frame is composed of four tracks.

FIG. 7 is a block diagram showing an example of a schematic configuration of a digital VTR. Next, the operation of the digital VTR will be explained with reference to FIG. A color video signal inputted from the input terminal is inputted to the A/D converter 2 through a low-pass filter (not shown).

The A/D converter 2 digitizes this color video signal using a sampling clock having a frequency of 4fsc (fsc: color subcarrier frequency). Since the amount of data in this digitized signal would be enormous, the output signal of the A/D converter 2 is compressed in a compression circuit 3 using a technique such as high-efficiency encoding, and then input to an encoder 4. Therefore, an error correction code is added.

The audio signal input to the input terminal similarly passes through the A/D converter 5 and is manually input to the encoder 4. Furthermore, data other than video and audio (hereinafter referred to as sub-data)
For example, the time and date of the image taken are digitized.
Again, the encoder 4 is manually operated. An error correction code is also added to these data by the encoder 4, and data shuffling is performed together with the previous video data. This is done by rearranging the order of the sent signals and dispersing the data in order to prevent it from becoming impossible to correct or correct when a large amount of data code errors occur due to dust on the tape or tape flaws. It is a method. These data outputted from the encoder 4 are distributed into four systems by the multiplexer 6, sent to each head amplifier 7.8°9.10, and recorded on the tape T through the heads H3 to H4.

In addition, in the case of playback, the signal on the tape T is transferred to the head) 11 to H.
4 pick up and playback amplifier 11.12, 13.1
After being amplified by 4, it is manually inputted to a demultiplexer 15 to form data of one system. This data string is further input to the decoder 16 and deshuffled to return it to the original order, and then the video
The data is separated into audio and sub-data, subjected to error correction, and output from the decoder 16.

The video data from the decoder 16 is decompressed by the decompression circuit 17 and inputted to the D/A converter 18.
An analog color video signal is obtained through a low-pass filter (not shown). The audio signal also passes through the D/A converter 19 and becomes an analog audio signal.

The sub data is output as a digital signal.

In such a digital VTR, data is recorded on one track of the tape as shown in FIG. 1st
Video data, audio data A, and sub data A are recorded in the second area, and audio data B and sub data B are recorded in the second area. A head run-up section is provided in front of each area, and a guard space for switching the head for post-recording is provided between the first area and the second area. In the case of normal recording, only the first area is used, and in the case of dubbing, the first area is reproduced and then recorded in the second area. Furthermore, when a large number of subdata or audio channels are to be recorded, the first area and the second area are used simultaneously.

[Problems to be Solved by the Invention] However, the above conventional example has the following problems. In other words, if you want to add audio information or sub-data to a tape that has data recorded in both the first area and the second area, you can play this tape once on a digital VTR, and then play it back on another digital VTH. It is necessary to record the data again along with new audio information and sub-data, which requires another digital VTR deck. Also, dubbing between digital VTRs causes much less signal deterioration than dubbing between analog VTRs, but if the dubbing is repeated many times, the data error rate increases.

In particular, image data tends to deteriorate more easily as the error rate increases. Furthermore, if the type and size of information to be added later is known in advance, data can be added by dividing one track by the number of pieces of additional information. However, when one track is divided, a guard space is required between each divided area, and a run-up period is required at the beginning of each area, regardless of the size of the area. Therefore, as the number of areas increases, the amount of information that can be recorded decreases, so unless the recording density can be increased, it will not be possible to accommodate future increases in the types of data.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems and provide an information recording/reproducing device that allows data to be easily rewritten.

[Means for Solving the Problems] An information recording/reproducing apparatus of the present invention includes a storage means for temporarily storing data reproduced by a recording/reproducing head from a predetermined portion of a recording track of a recording medium, and at least part of the data in the means. and an auxiliary head arranged to follow the trace trajectory of the previous recording/rewriting head after a predetermined period of time; The configuration allows the recorded contents to be rewritten.

[Function] According to the present invention, in addition to the recording/reproducing head that performs normal recording and reproduction, a head that traces the same recording track after a time delay longer than the time required for writing, rewriting, and reading data to the storage means is provided. By providing this, it is possible to rewrite or add some data while reproducing all the data recorded on a certain track.

[Embodiment] FIG. 2 shows the arrangement of heads on a rotating drum in a digital VTR, which represents the features of the present invention.

In FIG. 2, 1 is a rotating drum, L, 82. H3 and H4 are heads fixed to the rotating drum 1. h
,, h2 are sub-heads fixed to the rotating drum 1 so as to be adjacent to the heads H, , H2, respectively,
) II and hl and H2 and h2 have the same azimuth, all heads are old, and hj (ii to 4. j-1 to 2) are capable of recording and reproducing, respectively.

The track pattern formed on the magnetic tape by these heads, the area recorded on each track, and the type of information are the same as before. However, data in the second area of the track scanned by the subhead and data in the second area of other tracks are shuffled separately, and data is not distributed across tracks scanned by the subhead and tracks not scanned.

FIG. 1 is a block diagram showing the main structure of a digital VTR according to an embodiment of the present invention, and the same parts as in FIG. 7 are designated by the same reference numerals. That is, 2.5 is the A/D converter, 3
is a compression circuit, 4 is an encoder, 6 is a multiplexer, 7
, 8, 9.10 are recording head amplifiers, 11.12.1
3.14 is a playback head amplifier, 15 is a demultiplexer, 16 is a decoder, 17 is an expansion circuit, 18.19 is a D
/A converter. 51 is an A/D converter which manually inputs the audio signal C for rewriting or addition. 20 is a mixer having memory, and includes an A/D
It is possible to write the output signal of the converter 51 and the sub-data C for rewriting or addition into the built-in memory.

Furthermore, the mixer 20 is capable of storing the audio signal and sub-data from the decoder 16 in its internal memory.

41 is an encoder to which the signal from the mixer 20 is input. A multiplexer 61 inputs the signal from the encoder 41. Recording head amplifiers 71 and 81 amplify the signal from the multiplexer 61 and supply it to the heads h, h2.

Video data, audio data A, audio data B, sub data A, and sub data B are stored in the old head (i-1) as before.
-4) is used to record on the magnetic tape according to the track pattern shown in FIG.

Now, assume that there is a magnetic tape on which information has been written in the first area and the second area as described above. These digital signals on the magnetic tape are transferred to the old heads (i-1 to 4).
picked up and played by the head amplifier 11, 12
, 13. Power the demultiplexer 15 through 14,
Here, the signals from each head are combined into one signal train. This signal string is then input to the decoder 16, where it is deshuffled and rearranged, and then video data and audio data A are generated.

B and sub data A and B are separated, each error corrected and output. The video data from the decoder 16 is expanded by an expansion circuit 17, and then transferred to a D/A converter 18.
The signal passes through a low-pass filter (not shown) and becomes an analog color video signal. The audio data (A, B) from the decoder 16 passes through the D-converter 19 and is output as analog audio signals A, B. Decoder 16
The sub-data from is used as a digital signal as is.

Next, the operation of partially rewriting or adding information written in the second area of the magnetic tape during the reproduction operation from the magnetic tape performed in this manner will be explained.

Of the signals from the decoder 16, only the signals written in the second area (audio signal B, sub data B) are sent to the mixer 2.
0 is stored in the built-in memory. Then, the audio signal C is added to or rewritten to the information recorded in the second area.
is passed through the A/D converter 51, and the sub data C is input directly to the mixer 20. (This input signal has an address code corresponding to the part of the information stored in the memory of the mixer 20 that is to be rewritten or added, and is assigned to a track that can be recorded using the subhead). Then, the conventional data is updated in this mixer 20, and the updated data is sent to the encoder 41.
to use human power. Note that data is not sent to the heads 111 to H4. The encoder 41 adds an error correction code to the human input signal, performs shuffling, and inputs the signal to the multiplexer 61, which distributes the signal to each recording head amplifier 71.81. Then, the signals passing through the recording head amplifiers 71 and 81 are transferred to the second area (for example, the third area) of the same track of the magnetic tape that the heads H1 and H2 have reproduced.
(indicated by diagonal lines in the figure). Note that since the recorded data is a digital signal, it can be overridden, so an erase head is not required when rewriting or adding data as described above.

The relative height of the old head and the head hj and the angle from the center are determined by the time it takes for the manually input audio signal C and sub data C to reach the head amplifier 7.8, the number of rotations of the rotating drum, etc. That is, heads H1, H
2 traces head h1. The time it takes for h2 to trace is the time required for writing and rewriting the memory in the mixer 20,
The time required is longer than that required for reading.

[Other Embodiments] In the above embodiments, no data is added or rewritten in the second area of the track that is not scanned by the subhead. That is, in FIG. 3, the shaded area is the area scanned by the subhead, and the second area of the track recorded by heads H3 and L is not scanned. However, head H, -H2→
143"""The information recorded in the order of H4 is transferred to head H3"
If it is possible to reproduce in the order of It4=L-H2, the head +13. The second area by Ha can also be rewritten. Specifically, heads H+, H3, t+ are set to the same azimuth, and head 142. Set H4 and h2 to different, same ↓ azimuths. Normally, the signal at the start of writing data for a frame is picked up before the frame is played back, and combined with the phase detection signal of the rotating drum, the first track of one frame is assigned to be played by head H1, but the phase detection of the rotating drum is Head H by shifting the timing of the signal
3 to the first track, the frame will be played back in the order of heads H3 → H4 → H, -H2 as shown in Figure 4, and the frame will be played back in the order of heads H3 → H4 → H, -H2, and the second frame of the track written with heads H3 and H4 during recording will be The area (area d in FIG. 4) can also be rewritten. Therefore, all the second areas of one frame (four tracks) can be rewritten, and the second areas can be used effectively.

As described above, conventionally, two VTRs were required to rewrite or add part of the data while reproducing the data written in the second area, but according to the present invention, one VTR is required.
The above is possible with TR. Furthermore, since it is not necessary to divide the recording area into many areas (two is sufficient), the amount of information that can be recorded is large. Note that the number of subheads to be added can be reduced depending on the amount of information to be rewritten, and even with a minimum of one head, sufficient additional subdata such as date and time can be recorded.

[Effects of the Invention] As explained above, according to the present invention, it is possible to partially rewrite or add information without deteriorating the information.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a schematic configuration of a digital VTR according to an embodiment of the present invention, Fig. 2 is a diagram showing the arrangement of heads on a rotating drum in this embodiment, and Fig. 3 is a track diagram in the VTR of this embodiment. 4 is a diagram showing a track pattern in another embodiment of the present invention. FIG. 5 is a diagram showing a head arrangement on a rotating drum of a conventional digital VTR. FIG. 6 is a diagram showing a head arrangement on a rotating drum of a conventional digital VTR. FIG. 7 is a block diagram showing a schematic configuration of a conventional digital VTR, and FIG. 8 is a diagram showing data arrangement on each track. 20...Mixer equipped with memory as storage means, 41...Encoder, 51...A/D converter, 61...Multiplexer, h, h2...Subhead, T...Magnetic tape . Fig. 1 Fig. 2 f-Fushi-4 Fig. 6

Claims (1)

[Scope of Claims] Storage means for temporarily storing data reproduced by a recording/reproducing head from a predetermined portion of a recording track of a recording medium; means for replacing at least part of the data in the means with other data; and pre-recording. It is characterized by comprising an auxiliary head arranged to trace the trace locus of the re-head after a predetermined time, and rewriting the recorded content of a predetermined portion of the recording track by supplying data in the storage means to the auxiliary head. Information recording and reproducing device.