JPH04355201A - Information recording/reproducing method - Google Patents

Abstract

PURPOSE:To prevent the deterioration of an image and the missing of additional information by making a flaw in the longitudinal direction inconspicuous and making an interpolation easy even when the flaw in the longitudinal direction is generated on a tape-shaped recording medium. CONSTITUTION:The information to be recorded on one (or several) track(s) out of information signals to be recorded on plural tracks to be formed in the diagonal direction with respect to the longitudinal direction of a tape (T), is divided into several information blocks by a serial/parallel converter, etc. Each of them are temporarily stored in memories (M1 to M4) and a combination (order) of these plural information blocks to be supplied to a parallel/serial converter (3) is recorded while switching them time to time by changeover switches (Sw1 to Sw4), and at the time of reproduction, the respective information blocks are re-arranged into the initial order by detecting the recording order of the respective information blocks by a recording order identification signal or the like, the signals are processed with the parallel/serial converter and outputted.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an information recording and/or reproducing method, and in particular, an information recording/reproducing method that can sufficiently prevent signal loss even if a tape-shaped recording medium has streak-like scratches in the longitudinal direction. Regarding.

0002

[Prior Art and Problems to be Solved by the Invention] In a tape-shaped recording medium such as a magnetic tape, a guide pole (without a rotating roller) exists on the side facing the magnetic layer.
The tape may be scratched in the longitudinal direction by dust or dirt attached to the fixed head. If the information recording track width is sufficiently large or the information density is low, there is almost no loss or attenuation of the information signal, so there is no problem. When the track width is very narrow and the recording density is high, as in the case of information recording using the trademark) method, signal attenuation or dropout may occur.
The higher the recording density, the more noticeable the signal dropout problem becomes.

[0003] As a specific symptom, in a VTR that mainly handles video signals, if there is a streaky scratch in the video track, a certain position on the display screen will be missing, leading to deterioration of the image quality. I'll be there. In particular, if the area where the vertical synchronization signal is recorded is scratched, normal image reproduction will be hindered. Furthermore, in the R-DAT method of information recording, as is well known, pilot signals and additional information (performance time information, title, ID code), etc. are recorded at predetermined positions on each track. are recorded at a fixed position within a track, that is, at the same position in the width direction of the tape (with a constant distance from the edge of the tape), so if a streak-like scratch occurs in the longitudinal direction of the tape at that position, adjacent tracks may There was a problem in that interpolation using the recorded signal could no longer be performed, making it impossible to display song titles, indexes, etc.

0004

[Means for Solving the Problems] The present invention provides that the recording position from the tape edge (the edge in the tape width direction) of the same type of information signal or the information signal that will be at the same position on the screen when displayed is , an information recording method in which an information signal to be recorded on one track is divided into a plurality of blocks so as to be different for each predetermined track, and then the blocks are exchanged and recorded; and an information signal recorded on a tape by such an information recording method. By providing an information reproducing method that generates a regular information signal by subjecting the reproduced information signal to a rearranging process that is opposite to the recording order rearranging process performed at the time of recording. The issue was resolved.

[0005]

[Embodiment] The information recording/reproducing method of the present invention records information while forming tracks diagonally with respect to the longitudinal direction of a tape-shaped recording medium (hereinafter, a magnetic tape will be used as a typical example thereof). It is assumed that the application is applied to a helical scanning type recording and/or reproducing device that performs both recording and reproducing, and is not limited to information recording and reproducing devices that perform both recording and reproducing. It is also applied to recording devices and information reproducing devices. The recording method and the reproduction method will be explained separately below.

First, the information recording method of the present invention will be explained. In the method of the present invention, as shown in FIG. 2, one track of the magnetic tape T is divided into blocks corresponding to N types of information (N is an integer of 2 or more), and the position or order of each block is determined. Its main feature is that it can be replaced and recorded. Note that in FIG. 2, the screen is divided into two in both the vertical and horizontal directions, but it may be divided into four in the vertical direction. In addition, in FIG. 2, N=4, so for convenience of explanation, a specific configuration example of an information recording/reproducing apparatus that can realize the information recording/reproducing method of the present invention will be described below as being divided into four blocks. I will list and explain.

FIG. 1 is a schematic block diagram of the main parts of an information recording apparatus 1 capable of realizing the information recording method of the present invention. In the figure, M1 to M4 are memories for data latches (temporary storage means), Sw1 to Sw4 is a changeover switch for changing the recording order, 3 is a parallel-to-serial converter (hereinafter also simply referred to as a "parallel-to-serial converter"), 5 is a recording track control circuit, D is a rotating drum, H1 is a recording head, H5
is a drum rotation detection head, which outputs a rotation pulse every time the drum D rotates once. The number of recording heads H1 is not limited to one, but since this is not directly related to the gist of the present invention, a pair is depicted as a representative. Alternatively, recording and reproduction may be performed using separate rotary heads.

Next, the operation of the information recording apparatus 1 shown in FIG. 1 will be explained. It should be noted that since it is assumed that the information signals ■ to ■ supplied to each of the memories M1 to M4 are digital signals, when handling analog signals such as color video signals, an A/D converter (not shown) is required. Convert it to a digital signal in advance with
After that, a D/A converter (not shown) may be connected to convert the signal back to an analog signal and then supply the signal to the recording head H1.

When the power switch provided on the main body of the apparatus is closed and the recording switch (none of which is shown) is turned on, the drum D rotates in the direction of arrow α at a rotational speed of, for example, 30 rps, and the magnetic tape T is rotated. The well-known tape running mechanism starts running in the direction of arrow β. The signal recorded here is
For convenience of explanation, if we use a video signal, a video signal in units of one field is converted into four information blocks ■ to ■ by a switching circuit (not shown) or a serial-to-parallel converter (hereinafter simply referred to as a "serial-to-parallel converter"). The signals are sequentially divided and supplied to the memories M1 to M4, respectively, where they are latched for a predetermined period of time (for example, about 1/30 second). In addition, in parallel with the input of each information block ■～■,
It is assumed that identification signals I1 to I4 indicating the number of information in each information block are latched in the memories M1 to M4, respectively, as the header (beginning) of each information block.

During the period when one track worth of signals is recorded,
The changeover switches Sw1 to Sw4 are connected to any one of the terminals a to d. And drum D
Rotation pulse synchronized with one rotation of drum Flip Fl
op) is obtained from the drum rotation detection head H5, and based on this, the recording track control circuit 5 generates a recording order switching signal and supplies it to the changeover switches Sw1 to Sw4, thereby switching the connected terminals in conjunction. ing. Note that as long as the switches Sw1 to Sw4 are switched to the terminals with the same number at the same time, the
It does not matter if it is every 2 rotations or more.

[0011] Now, changeover switches Sw1 to Sw4
Assuming that is connected to terminal a as shown in the figure, the recording signals from the parallel-to-serial converter 3 are in the order of ■, ■, ■, ■. In the next track, all switches Sw1
~Sw4 is connected to the terminal b, for example, and the order of each block of the recording signal becomes ■, ■, ■, ■. Similarly, when connected to terminals c and d, the order of the signal blocks becomes ■, ■, ■, ■→■, ■, ■, ■, and goes around. Therefore, the recording pattern of the magnetic tape T is as shown in FIG. Arrows α and β indicate the running directions of the recording head H1 and the magnetic tape T, respectively. In addition, this figure 3 and figure 2
Although adjacent tracks are spaced apart from each other, this is for the purpose of making it easier to see, and does not imply the presence or absence of a guard band or its width.

The recording track control circuit 5 is specifically constructed with a counter and the like, and includes a drum rotation detection head H5.
The count value is increased one by one by the rotation pulse from , and when it exceeds 3, it is cleared to 0, and the changeover switches Sw1 to Sw4 are simultaneously connected to the same terminals a to d according to each count value. ing. That is,
It operates according to the flowchart shown in FIG.

In the above configuration example (embodiment) of FIG. 1, the information signals within one track are rotated for each track, but this is not limited to this as long as the identification signal can be read correctly. , the order may be rearranged for each track and arranged at random. Furthermore, it is also possible to use a microcomputer or the like to replace the information in each block using software and supply it to each input terminal of the serial-to-parallel converter 3.

Another example of a configuration (implementation) in which information signals within one track are replaced at a constant rotation will now be described with reference to FIG. In FIG. 5, the same components as those in FIG. 1 are given the same numbers, and detailed explanation thereof will be omitted. In the device 1 of the first embodiment shown in FIG. 1, an identification signal is attached as a header to each information block, whereas in the device 2 of the second embodiment, a record indicating the start of the rotation of information blocks is recorded. A sequence (identification) signal is generated by a recording track control circuit 5, and is recorded on a CTL (control) track of the tape T by a CTL head H6.

According to this configuration, by giving the rotation a regularity of order as shown in FIG.
This has the advantage that even if the recording order signal is missing to some extent, there will be no problem during playback. Note that this recording order signal is
It may be configured to record not only on the CTL track but also on an information signal recording track (using the recording head H1) or an audio signal recording track (using a known fixed head).

Next, to explain the principle and specific configuration example of the information reproducing method of the present invention, first, the information recording apparatus 1 of the first embodiment collects information from the magnetic tape T recorded as shown in FIG. The information reproducing device 11 for reproducing signals will be explained with reference to FIG. In the figure, 4 is a serial-to-parallel converter (hereinafter simply referred to as a "serial-to-parallel converter"), 7 is a rearrangement judgment circuit, and 8 is a waveform shaping circuit. The waveform shaping circuit 8 shapes the latch signals supplied to the memories M5 to M8 into digital signal waveforms.

The signal detected (picked up) by the reproducing head H2 (when implemented in an information recording/reproducing apparatus, the recording head H1 can also be used as a recording/reproducing head) is sent to the A/D as necessary. After the conversion, the serial-parallel converter 4 divides the data into four information blocks (1) to (4) and latches the data for a predetermined time {approximately equal to the time required to trace one track}. Then, by the same switching means as in the recording, the order of the 4
After returning the two pieces of information to their original order (■, ■, ■, ■), they are subjected to parallel-to-serial conversion if necessary, and are further D/A converted if necessary and output.

[0018] As mentioned above, each information block ■~■
Since the beginning (header) includes identification signals I1 to I4 indicating the number of the information, the serial-to-parallel converter 4 reads the identification signals along with each information block ■ to ■ and rearranges the information. Each information block ■～■ in the judgment circuit 7
The switching of the switch is controlled by determining the recording order. The judgment algorithm in this rearrangement judgment circuit 7 is as shown in FIG.
4, the changeover switches Sw5 to Sw8 are selectively connected to any of the connection terminals a to d as shown in this diagram.

Furthermore, since this identification signal is recorded at the beginning of every information block, even if one identification signal is missing due to the streaky scratches, for example, three or more of them will match. There is no risk that the reordering judgment circuit 7 will interfere with the judgment of the recording order, and furthermore, the possibility that all four identification signals will be lost is extremely small. , there is no practical problem.

Finally, the information recording device 2 of the second embodiment
A method for reproducing an information signal from a magnetic tape T recorded by the above method will be explained with reference to an information reproducing apparatus 12 shown in FIG. 8, which is a specific example of its configuration. In this FIG. 8, 9 is a rearrangement control circuit, LC is a latch clock input terminal of each memory M5 to M8, and other components that are the same as those in FIG. 6 are given the same numbers and detailed explanations thereof are omitted. do.

The outline of the operation is almost the same as that of the first embodiment of the information reproducing apparatus shown in FIG.
The selection of w5 to Sw8 is made using the recording order identification signal detected and reproduced by the CTL head H6 from the CTL track of the tape T, and the drum rotation detected by this identification signal and the drum rotation detection signal transmitted from the drum rotation detection head H5 to the waveform shaping circuit 8. The pulses are supplied to the rearrangement control circuit 9, which generates control signals based on these signals and switches Sw5 to Sw8.
This is done by supplying the An operational flowchart of this rearrangement control circuit 9 is shown in FIG.

[0022] In the above explanation, an example was given in which one track is divided into four blocks and then rearranged for recording and reproduction.
=4, but may be N≧2. Also, 1
It is not limited to the tracks of a book, but it is also easily applicable to divide a plurality of tracks into more blocks and rearrange them across different tracks for recording and reproduction.

[0023]

Effects of the Invention Since the information recording/reproducing method of the present invention records and/or reproduces information as described above, scratches in the longitudinal direction of the tape, which occur relatively frequently among the damages that may occur on the tape, can be avoided. Even if it occurs, it is made less noticeable and easier to interpolate. That is, it has the following characteristics. (2) When the signal to be recorded is video information, damage to pixels is dispersed over time and at screen positions, making it less noticeable, and interpolation from the time direction (for example, interpolation from previous and subsequent frames) can be applied. ■If the signal to be recorded is the additional information, the recording position of the same type of information from the edge of the tape is dispersed in each track, so the continuous damage time for the same information is sufficiently short, and even if there is a loss of information, Since the duration of time remains short, it is possible to make inferences based on previous and subsequent information, and even detailed time-based information can be handled with confidence. ■Can be achieved by adding a relatively simple circuit configuration.

[Brief explanation of the drawing]

FIG. 1 is a main block configuration diagram of a first embodiment apparatus capable of implementing the information recording method of the present invention.

FIG. 2 is a principle diagram schematically showing information recording on a magnetic tape by the information recording method of the present invention.

FIG. 3 is a schematic diagram showing an example of a recording pattern of a magnetic tape recorded by the method of the present invention.

FIG. 4 is a flowchart for explaining a recording track control method in the information recording method of the present invention.

FIG. 5 is a main block configuration diagram of a second embodiment device capable of implementing the information recording method of the present invention.

FIG. 6 is a main block configuration diagram of a first embodiment device capable of implementing the information reproducing method of the present invention.

FIG. 7 shows a determination algorithm in a rearrangement determination circuit that constitutes the information reproducing apparatus of FIG. 6;

FIG. 8 is a main block configuration diagram of a second embodiment device capable of implementing the information reproducing method of the present invention.

9 is a flowchart for explaining the operation of a rearrangement control circuit that constitutes the information reproducing apparatus of FIG. 8;

[Explanation of symbols]

1, 2... Information recording/reproducing device, 3... Para-serial converter, 4
... Serial-to-parallel converter, 5... Recording track control circuit, 7... Sorting judgment circuit, 8... Waveform shaping circuit, 9... Sorting control circuit, 11, 12... Information reproducing device, D... Rotating drum, H
1...recording head, H2...playback head, H5...drum rotation detection head, H6...CTL head, M1 to M
8...Memory, Sw1 to Sw8...Selector switch,
T...Magnetic tape.

Claims (6)

[Claims] Claim 1: A helical scanning information recording method in which information signals are recorded while forming a number of tracks diagonally at a predetermined angle with respect to the longitudinal direction of a tape-shaped recording medium, wherein the information signals of the same type or Replace the information signals recorded on one track so that the recording position from the edge of the tape-shaped recording medium of the information signal at the same position on the screen when displayed is different for each predetermined track. An information recording method characterized in that information is recorded using the following methods. 2. The information recording method according to claim 1, wherein the information signal recorded on one track is divided into a plurality of blocks and replaced, and each divided block is assigned the order of the replacement or information. An information recording method in which an identification signal indicating the type is added and recorded. 3. In the information recording method according to claim 1 or 2, the information signal recorded on one track is
A predetermined plurality of tracks are rotated and recorded in a predetermined order, and an identification signal indicating the rotation order standard is associated with at least one track for each one or more rotations. A method for recording information on a storage medium. 4. An information reproducing method for reproducing information signals recorded on a tape-shaped recording medium by the information recording method according to claim 1, 2, or 3, wherein each of the reproduced information signals An information reproducing method characterized in that a regular information signal is generated by subjecting the blocks to a rearrangement process that is the reverse of the recording order rearrangement process performed when recording the information signal. 5. The information reproducing method according to claim 4, wherein the information signal recorded by adding an identification signal to each block is reproduced, wherein the identification signal is extracted from the reproduced signal, and based on the identification signal. Perform the above-mentioned swapping of each block,
An information reproduction method that generates a regular information signal. Claim 6: Claim 4, wherein the information signal is reproduced in a rotating manner for each of a plurality of predetermined tracks.
The information reproducing method described above reproduces an identification signal indicating a reference for rotation order, detects a rotation reference track based on the identification signal, and replaces the recording order performed when recording the information block. is an information reproduction method that generates a regular information signal by performing reverse permutation processing.