JP2004310862A - Recording and reproducing device and recording and reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable converging at high speed, accurately, and surely a reproducing head to a recording track being reference of a magnetic tape. <P>SOLUTION: This device is a device recording digital information in a magnetic tape 80 or/and reproducing digital information from the magnetic tape 80, the device is provided with a recording and reproducing means 4 which records a servo pilot signal of a frequency of 8T in a recording track being reference of the magnetic tape 80, while replaces a right side with a left side every other line for the recording track and records a servo pilot signal of a frequency of 80T in an adjacent recording track, replacing a right side with a left side alternately every other line for the recording track of this magnetic tape and reproduces the servo pilot signal of a frequency of 80T from an adjacent recording track, while reproduces the servo pilot signal of a frequency of 8T from the recording track being reference. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
INDUSTRIAL APPLICABILITY The present invention relates to a recording / reproducing apparatus suitable for application to home and business video recording / reproducing apparatuses for recording digital information on a tape recording medium and / or reproducing digital information from the tape-recording medium. Reproduction method.
[0002]
Specifically, the information recording medium includes a reproducing unit for reproducing digital information from the information recording medium, and the recording track of the information recording medium is alternately replaced on the right side and the left side alternately with every other recording track. While reproducing the servo control signal, the servo control signal of the first frequency is reproduced from the reference recording track, and the servo control signal of the first frequency is reproduced continuously from the initial head pull-in based on the servo control signal of the second frequency reproduced from the recording track. A head pull-in operation based on a one-frequency servo control signal can be executed, and a reproducing head or the like can quickly, accurately, and surely converge on a reference recording track.
[0003]
[Prior art]
2. Description of the Related Art In recent years, video recording / reproducing apparatuses that record digital information on a tape recording medium and / or reproduce digital information from the tape recording medium for home use and business use are often used. A cassette around which a magnetic tape is wound is mounted on this type of video recording / reproducing apparatus.
[0004]
The video data and audio data recorded on the magnetic tape are reproduced by, for example, eight reproduction magnetic heads (hereinafter, referred to as reproduction heads). Video data and audio data are recorded on the magnetic tape in a predetermined recording format. In addition to the digital information, a control signal called a servo pilot (hereinafter, also referred to as a servo control signal) for pulling a recording head, a reproducing head, and the like to a tracking target position is recorded on the magnetic tape.
[0005]
In the conventional method, every time the recording head scans on the magnetic tape, a servo pilot of a predetermined frequency is recorded in one location of a recording track serving as a reference. At the time of editing, the direction of retracting the reproducing head is determined based on the reproducing timing of the servo pilot signal, and the reproducing head is retracted to the tracking target position based on the determination result.
[0006]
Patent Document 1 discloses a portable camera-integrated digital video tape recorder. According to this video tape recorder, the video signal captured by the video camera is band-limited by the band-limiting means, and then the signal subjected to band compression processing by the bit rate reduction encoder circuit is recorded on the tape recording medium. With this configuration, the size and weight of the video tape recorder can be reduced, and the power consumption can be reduced.
[0007]
[Patent Document 1]
JP-A-9-247709 (pages 2 to 4, FIG. 1)
[0008]
[Problems to be solved by the invention]
By the way, according to the conventional video recording / reproducing method, at the time of data recording, every time the recording head scans on the magnetic tape, a servo pilot having a predetermined frequency is recorded in one place on a recording track serving as a reference. Therefore, there are the following problems.
[0009]
{Circle around (1)} In the tracking processing at the time of editing, a method is adopted in which a servo pilot signal of a predetermined frequency is controlled to climb a hill to converge a recording head and a reproducing head to a tracking target position. Is not known, and as a result, the number of times of sampling increases, and much time is spent until the recording head and the reproducing head converge to the tracking target position.
[0010]
{Circle around (2)} On the other hand, there is also known a method in which the direction of pulling in the reproducing head or the like is determined at the timing of reproducing the servo pilot signal, and the head is retracted. However, according to this method, a sufficient output (signal / noise ratio; SN) for judging the reproduction timing of the servo pilot signal is required for the initial off-track. Therefore, a malfunction may occur in a recording / reproducing system with insufficient SN or a recording format with a narrow pitch in which the initial off-track is relatively large.
[0011]
{Circle around (3)} According to Patent Literature 1, after a video signal captured by a video camera is band-limited, a signal subjected to band compression processing by a bit rate reduction encoder circuit is recorded on a tape recording medium. However, when the function of the portable camera-integrated digital video tape recorder disclosed in Patent Document 1 is applied as it is, the same problem as in the cases (1) and (2) occurs.
[0012]
Accordingly, the present invention has been made to solve such a conventional problem, and a recording / reproducing apparatus which enables a reproducing head or the like to quickly, accurately, and reliably converge on a reference recording track on an information recording medium. It is an object to provide an apparatus and a recording / reproducing method.
[0013]
[Means for Solving the Problems]
An object of the present invention is to provide an apparatus for recording digital information on an information recording medium and / or reproducing digital information from the information recording medium, wherein a first frequency servo control is performed on a reference recording track on the information recording medium. Recording means for recording a signal, recording the servo control signal of the second frequency on an adjacent recording track by exchanging the right and left sides of the recording track every other track, and recording the information recorded by the recording means The right and left sides of the recording track of the medium are alternately replaced with each other to reproduce the servo control signal of the second frequency from the adjacent recording track and the servo control of the first frequency from the reference recording track. The recording / reproducing apparatus is provided with a reproducing means for reproducing a signal.
[0014]
According to the recording / reproducing apparatus according to the present invention, when digital information is recorded on the information recording medium and / or when the digital information is reproduced from the information recording medium, the recording means uses the information recording medium when recording the information. A servo control signal of the first frequency is recorded on the reference recording track, and the right and left sides of the recording track are switched every other track, and the servo control signal of the second frequency is recorded on the adjacent recording track. Is recorded. On the premise of this, at the time of reproducing information, the reproducing means alternately alternates the right and left sides of the recording track of the information recording medium previously recorded by the recording means with every other recording track from the adjacent recording track. The second frequency servo control signal is reproduced, and the first frequency servo control signal is reproduced from the reference recording track.
[0015]
Accordingly, it is possible to execute the head pull-in based on the servo control signal of the first frequency following the initial head pull-in based on the servo control signal of the second frequency reproduced from the recording track. As a result, the reproducing head or the like can quickly, accurately, and surely converge on the reference recording track. In addition, in a recording / reproducing system in which the SN is not sufficient for timing detection in the conventional method, or in a format having a relatively large initial off-track and a narrow pitch, it is possible to achieve both high precision and high speed in the head pull-in process. Can be achieved.
[0016]
A recording / reproducing method according to the present invention is a method of recording digital information on an information recording medium and / or reproducing digital information from the information recording medium. A servo control signal of a first frequency is recorded on a recording track, and a servo control signal of a second frequency is recorded on an adjacent recording track by exchanging the right and left sides of the recording track every other one. During reproduction of the information recording medium, the right and left sides of the recording track are alternately replaced with each other on the information recording medium, and the servo control signal of the second frequency is reproduced from the adjacent recording track to pull in the initial head of the recording / reproducing system. And reproduces the servo control signal of the first frequency from the reference recording track continuously with the initial head pull-in, and It is characterized in performing a pulling head.
[0017]
According to the recording / reproducing method according to the present invention, when recording digital information on an information recording medium and / or reproducing digital information from the information recording medium, a high-speed recording on a recording track based on a recording / reproducing system is performed. Convergence can be achieved accurately and reliably. In addition, in a recording / reproducing system in which the SN is not sufficient for timing detection in the conventional method, or in a format having a relatively large initial off-track and a narrow pitch, it is possible to achieve both high precision and high speed in the head pull-in process. Can be achieved.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of a recording and reproducing apparatus and a recording and reproducing method according to the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration example of a VTR 100 to which a recording / reproducing apparatus as an embodiment according to the present invention is applied.
In this embodiment, a reproducing means for reproducing digital information from the information recording medium is provided, and the recording tracks of the information recording medium are alternately replaced on the right and left sides alternately with every other recording track. While reproducing the servo control signal of the frequency, the servo control signal of the first frequency is reproduced from the reference recording track, and the initial head pull-in based on the servo control signal of the second frequency reproduced from the recording track is continued. In this way, the head pull-in operation based on the servo control signal of the first frequency can be executed, and the reproducing head and the like can quickly, accurately and reliably converge on the reference recording track.
[0019]
The VTR 100 shown in FIG. 1 is an example of a recording / reproducing device, and is a device that records digital information on a magnetic tape 80 as an example of an information recording medium and / or reproduces digital information from the magnetic tape 80. The VTR 100 is suitable for application to home and business video recording / reproducing devices. The VTR 100 has a recording / reproducing means 4, a video compression circuit 10, a parity addition circuit 20, a video input terminal 110 and an audio input terminal 130.
[0020]
The recording / reproducing unit 4 is an example of a recording unit and a reproducing unit, and records a servo control signal (hereinafter, referred to as a servo pilot signal) of a first frequency on a reference recording track (C and G) on the magnetic tape 80 during data recording. At the same time, the servo control signal of the second frequency is recorded on adjacent recording tracks (B and H) with the right and left sides being switched every other recording track.
[0021]
In this example, the second frequency is set lower than the first frequency for the servo pilot signal. In the initial stage, the head is roughly pulled into the tracking target position based on the servo pilot signal of the second frequency, and in the subsequent successive period, the head is densely moved to the tracking target position based on the servo pilot signal of the first frequency. This is because the head is drawn into. This makes it possible to avoid unnecessary vibrations and the like and to quickly and accurately converge the head to the tracking target position as compared with the case where tracking is performed based on the servo pilot signal of the first frequency from the initial stage. .
[0022]
Further, at the time of data reproduction, the recording / reproducing means 4 alternates the right and left sides of the recording track of the magnetic tape 80 alternately every other recording track, and shifts the recording tracks of the second frequency from the adjacent recording tracks (B and H). In addition to reproducing the servo control signal, the servo control signal of the first frequency is reproduced from the reference recording tracks (C and G).
[0023]
A video compression circuit 10 is connected to a video input terminal 110 of the VTR 100, and a recording video signal VSin output from a video camera or the like is input and compressed. For example, the video compression circuit 11 divides the recording video signal VSin into a two-dimensional block of 8 × 8 pixels, and performs data compression processing using block coding such as DCT.
[0024]
A parity addition circuit 20 is connected to the video compression circuit 10 and receives the video data (compression-encoded data) Dv after the compression processing and the recording audio signal ASin. The error correction encoding process using the product code is performed for each recording, and the error correction encoding process using the product code is performed on the recording audio signal ASin.
[0025]
The recording / reproducing means includes a servo pilot adder 30, head selection switch circuits 41, 42, 43 and 44, a helical recording head 50, an 8T band-pass filter circuit (hereinafter referred to as an 8T BPF circuit) 61, and an 80T band-pass filter. The circuit includes a circuit (hereinafter referred to as an 80T BPF circuit) 62, two detectors 71 and 72, and a microcomputer (hereinafter referred to as a servo microcomputer) 90 for servo control.
[0026]
A servo pilot adder 30 is connected to the parity adding circuit 20 to add 8T and 80T servo pilot signals (CTL signals) to the error-corrected video data + audio data VDb. A pilot signal is recorded. Here, 8T refers to a period eight times as long as one period T of the reference frequency, and constitutes a first frequency.
[0027]
Similarly, 80T refers to a cycle that is 80 times as long as one cycle T of the reference frequency, and constitutes a second frequency. Therefore, the frequency of the 8T servo pilot signal is ten times higher than the frequency of the 80T servo pilot signal. The 8T servo pilot signal is used at the time of tracking to perform final pull-in on the reference recording tracks (C and G). The 80T servo pilot signal is used at the time of the same tracking to perform initial head pull-in on the same recording track (C and G).
[0028]
Four head selection switch circuits 41, 42, 43, and 44 are connected to the servo pilot adder 30, and the helical recording head 50 is switched to execute 180-degree facing recording. Each of the head selection switch circuits 41, 42, 43, and 44 has a two-circuit one-selection switch function.
[0029]
The helical recording head 50 has eight recording heads RECA to RECH for A channel to H channel. In this example, at the time of data recording, a servo pilot signal of the first frequency (8T) is recorded on the reference C and G recording tracks on the magnetic tape 80. At the same time, a servo pilot signal of the second frequency (80T) is recorded on the adjacent B and H recording tracks with the right and left sides being switched every other C recording track and the G recording track. The two recording heads RECC and RECG of the C channel and the G channel are also used at the time of pilot reproduction.
[0030]
The head selection switch circuit 41 is connected to the recording head (RECA) for A channel (ch) and the recording head (RECE) for Ech, and selects one of the recording heads based on the switch selection signal Ssw. Is made. For example, at the time of data recording, the head selection switch circuit 41 outputs the video data + audio data VDb after the addition of the servo pilot signal to the Ach recording head or the Ech recording head.
[0031]
The head selection switch circuit 42 is connected to the recording head (RECB) for Bch and the recording head (RECF) for Fch, and selects one of the recording heads based on the switch selection signal Ssw. For example, at the time of data recording, the head selection switch circuit 42 outputs the video data + audio data VDb after the addition of the servo pilot signal to the Bch recording head or the Fch recording head.
[0032]
The head selection switch circuit 43 is connected to the recording head (RECC) for Cch and the recording head (RECG) for Gch, and selects one of the recording heads based on the switch selection signal Ssw. For example, at the time of data recording, the head selection switch circuit 43 outputs the video data + audio data VDb after the addition of the servo pilot signal to the Cch recording head or the Gch recording head.
[0033]
The head selection switch circuit 44 is connected to the Dch recording head (RECD) and the Hch recording head (RECH), and selects one of the recording heads based on the switch selection signal Ssw. For example, the head selection switch circuit 44 outputs the video data + audio data VDb to which the servo pilot signal has been added to the Dch recording head or the Hch recording head during data recording. The switch selection signal Ssw is supplied from the servo microcomputer 90 to each of the head selection switch circuits 41, 42, 43 and 44 as a switching pulse (SW'Pulse) signal.
[0034]
The 8T BPF circuit 61 and the 80T BPF circuit 62 are connected to the head selection switch circuit 43 connected to the above-described Cch recording head and Gch recording head. The 8T BPF circuit 61 functions as a bandpass filter for passing only an 8T frequency servo pilot signal reproduced by the recording head (RECC) or the recording head (RECG) during editing or the like. The 80T BPF circuit 62 functions as a bandpass filter for passing the servo pilot signal of the 80T frequency reproduced in the same manner.
[0035]
A detector 71 is connected to the 8T BPF circuit 61 so as to detect only a filtered servo pilot signal having a frequency of 8T. A detector 72 is connected to the 80T BPF circuit 62 so as to detect only a filtered servo pilot signal having a frequency of 80T.
[0036]
To these detectors 71 and 72, a servo microcomputer 90 as an example of a control means is connected. A servo pilot signal having a frequency of 8T is input from the detector 71, and a servo pilot signal having a frequency of 80T is supplied to the detector 72. Is entered from At the time of editing, the servo microcomputer 90 converts an 8T frequency servo pilot signal into an 8T frequency servo head signal following the initial head pull-in based on the 80T frequency servo pilot signal reproduced from the recording track by the Cch recording head and the Gch recording head. Based on this, the final head retraction is executed.
[0037]
A control terminal 19 is connected to the servo microcomputer 90, and outputs a capstan drive signal SCp to the capstan drive unit (not shown) through the control terminal 19. The capstan driving unit is capstan driven so as to move the magnetic tape 80 in a predetermined running direction based on the capstan driving signal SCp. Of course, the drive of a dynamic tracking (DT) driver (not shown) may be controlled in accordance with the capstan driving.
[0038]
FIG. 2 is a block diagram showing an example of the internal configuration of the parity adding circuit 20. The parity adding circuit 20 shown in FIG. 2 has an SDRAM (Synchronous Dynamic RAM) 31 and an SDRAM interface 32 which is an interface for writing and reading to and from the SDRAM 31. The SDRAM 31 has a capacity capable of storing video data Dv of a plurality of fields. In this case, the SDRAM 31 has a memory space corresponding to 36 ECC blocks for each of the Rch and Lch fields.
[0039]
An input write buffer 33 is connected to the SDRAM interface 32, and serves as a buffer for writing the video data (compression-coded data) Dv supplied from the video compression circuit 11 to the SDRAM 31. A video C2 read buffer 34 is connected to the SDRAM interface 32 and serves as a buffer for supplying video data Dv corresponding to 36 ECC blocks read from the SDRAM 31 to a video C2 encoder 35 described later. .
[0040]
A C2 encoder 35 is connected to the C2 read buffer 34, and calculates C2 parity (outer code parity) in 36 ECC blocks for each field. The C2 encoder 35 has 36 calculators for calculating the C2 parity, and can calculate the C2 parity in the 36 ECC blocks in parallel. Therefore, video data corresponding to 36 ECC blocks is supplied from the C2 read buffer 34 to the C2 encoder 35 in parallel. In that case, the video data of each ECC block is supplied in the order of the data of the sync blocks “0 to 113”.
[0041]
Further, a C2 write buffer 36 is connected to the C2 encoder 35, and serves as a buffer for writing the C2 parity in the 36 ECC blocks calculated by the C2 encoder 35 to the SDRAM 31 for each field. Further, an output read buffer 37 is connected to the SDRAM interface 32, and serves as a buffer for outputting video data and C2 parity corresponding to 36 ECC blocks read from the SDRAM 31 for each field.
[0042]
The video data Dv is input in the order of C1 = sync. This is because compressed macroblocks are packed in sync units. In this way, when one sync hit occurs during shuttle playback, the corresponding macroblock can be updated. Therefore, the video data Dv is written in the C1 direction, and then read out in the C2 direction to perform the C2 correction processing. On the other hand, the audio data Da does not require the same processing as the video data Dv, and is written into the SDRAM 31 after integrating the C2 code.
[0043]
For example, an input buffer 310 for audio is connected to the SDRAM interface 32 and serves as a buffer for inputting the recording audio signal ASin supplied from the audio input terminal 130. An audio C2 encoder 311 is connected to the input buffer 310, and calculates C2 parity (outer code parity) in 24 ECC blocks for each field. In this C2 correction process, the recording audio signal ASin is input in the order of C2 columns. An audio C2 write buffer 312 is connected to the C2 encoder 311 and serves as a buffer for writing audio data Da and C2 parity corresponding to 24 ECC blocks to the SRAM 31 via the SDRAM interface 32 for each field. .
[0044]
Further, a SYNC / ID adding circuit 38 is connected to the output read buffer 37, and the sync data and ID are added to the data string of video data (or C2 parity) of each sync block output from the output read buffer 37 in the recording order. It is made to add. The SYNC / ID adding circuit 38 is connected to a C1 encoder 39, calculates and adds C1 parity to video data and audio data Da of each sync block to which sync data and ID are added, and adds video data Dv + Audio data Da is output as recording data VDb.
[0045]
FIG. 3 is a conceptual diagram showing a configuration example of the rotating drum 140 according to the VTR 100 shown in FIG. The rotary drum 140 shown in FIG. 3 is equipped with a helical recording head (magnetic head) 50 and a helical reproducing head 55. For example, the magnetic tape 80 is obliquely wound around the rotary drum 140 at a winding angle of 180 degrees. The magnetic tape 80 runs at a predetermined speed while being wound around the rotating drum 140 in this manner.
[0046]
In addition, four recording heads RECA to RECD are arranged on the rotating drum 140, and four recording heads RECE to RECH are arranged at an angular interval of 180 degrees with respect to the four recording heads RECA to RECD. Are located. Further, on the rotating drum 140, eight reproducing heads PBA to PBH corresponding to the recording heads RECA to RECH are arranged at 90-degree angular intervals with respect to the recording heads RECA to RECH.
[0047]
That is, the helical recording head 50 is composed of eight recording heads RECA to RECH, and the helical reproducing head 55 is composed of eight reproducing heads PBA to PBH. In this example, the two recording heads RECC and RECG of the C channel and the G channel are used also at the time of pilot reproduction at the time of reproduction. However, the present invention is not limited to this. You may.
[0048]
FIG. 4 is a diagram showing an example of a recording format on the magnetic tape 80. On the magnetic tape 80 shown in FIG. 4, tracks T inclined with respect to the longitudinal direction are sequentially formed. In this case, the recording azimuths in the two tracks T adjacent to each other are made different. The areas on the scanning start end side and the scanning end end side of the track T are respectively a video data area ARV. _L , ARV _U Assigned to. This video data area ARV _L , ARV _U Records video data Dv output from the parity adding circuit 20 described above. Also, the video area ARV of the track T _L , ARV _U Are allocated to the audio data area ARA. Audio data Da is recorded in this area ARA.
[0049]
FIGS. 5A and 5B are diagrams showing examples of a VTR format (footprint) in which a video sync (M) and an audio sync (N) are mixed.
[0050]
In this embodiment, 8-head recording (4 heads + 4 heads opposing recording) is premised, and a servo pilot having a frequency of 8T is provided on one reference recording track (C and G) every time the head is scanned. A signal is recorded, and a servo pilot signal having a frequency of 80T is recorded in only one of the adjacent tracks (B and H), and the other (D and F) is recorded in the same 2T as the gap without recording the pilot. Another signal is being recorded at the frequency. In the magnetic tape 80, one field of video data Dv is recorded on each of 12 tracks. At the time of recording and reproduction, four tracks are simultaneously scanned by four heads in one scan, so that 12 tracks are scanned by three scans.
[0051]
The footprint (ECC configuration and data recording format) shown in FIG. 5A is a format recorded by the helical recording head 50 shown in FIG. In this example, the video sync (M) is divided before and after the track, and the area of the audio sync (N) is allocated between them. A servo pilot signal is arranged between the first video sync (M) and the audio sync (N). Although the number of edit gaps is the same as that of the conventional system, since the servo pilot signal is located at a portion where the video sync (M) shifts to the audio sync (N), the video necessary for performing the C1 correction process is determined. A sufficient signal processing space between the sync (M) and the audio sync (N) can be secured.
[0052]
In the 12 tracks × 2 fields of the footprint shown in FIG. 5A, each of the 12 tracks has the video data area ARV shown in FIG. _U Are arranged in an upper video sync (sync: (M)). This video sink (M) has 36 ECC blocks (codes) from block “0” to table “35” as shown in FIG. Data of the conversion unit) is recorded. Video data of field f0 is recorded on the right 12 tracks, and video data of field f1 is recorded on the 12 left tracks.
[0053]
Similarly, the lower video sink (M) shown in FIG. 5A has the video data area ARV shown in FIG. _L The video sync (M) records 36 ECC blocks (data in units of coding) from block “0” to block “35” as shown in FIG. Similarly, video data of field f0 is recorded on the right 12 tracks, and video data of field f1 is recorded on the 12 left tracks. The size of each of the upper and lower video syncs (M) is 12 tracks × 189 bytes. An audio sync (N) is arranged between the upper and lower video syncs (M), and audio data Da is recorded. The audio sink (N) is divided into eight sections, and the size of one section is 4 bytes × 12 tracks.
[0054]
Here, assuming that the helical recording head 50 as shown in FIG. 3 is scanned from the lower video sink (M) side to the upper video sink (M) side, in the right 12 tracks, the first section is Audio data A1, A9, A5 are arranged, audio data A2, A10, A6 are arranged in the second division, audio data A3, A11, A7 are arranged in the third division, and audio data is arranged in the fourth division. A4, A12 and A8 are arranged, audio data A5, A1 and A9 are arranged in the fifth section, audio data A6, A2 and A10 are arranged in the sixth section, and audio data A7 and A7 are arranged in the seventh section. A3 and A11 are arranged, and audio data A8, A4 and A12 are arranged in the eighth section. Similarly, audio data A1 to A12 are arranged in the 12 tracks on the left side.
[0055]
Further, a gap Gav is arranged between the upper video sync (M) and the audio sync (N) in the eighth section. A gap Gaa is arranged between the audio sinks of each section. A servo pilot signal (CTL signal) is arranged between the audio sync (N) in the first section and the lower video sync (M). A gap Gs1 is arranged between the lower video sync (M) and the servo pilot signal, and a gap Gs2 is arranged between the servo pilot signal and the lower video sync (M). This is to secure a signal processing space during reproduction.
[0056]
FIG. 5B is an enlarged view showing a recording example of a servo pilot signal of 12 tracks × 2 fields of the footprint shown in FIG. 5A. Here, the recording order indicated by the arrows is A, B, C, D, E, F, G, H from right to left on the page.
[0057]
In FIG. 5B, a servo pilot signal having a frequency of 8T shown in the plain ground is recorded (recorded) on the 12 recording tracks B on the left side, and a servo pilot signal having a frequency of 80T shown in the diagonal lines is recorded on the recording track C. A servo pilot signal having a frequency of 80T indicated by oblique lines is recorded on a recording track G, and a servo pilot signal having a frequency of 8T indicated by a blank is recorded on the recording track H. Subsequently, the recording track B is recorded with a servo pilot signal having a frequency of 8T shown in a blank area, and the recording track C is recorded with a servo pilot signal having a frequency of 80T shown in oblique lines.
[0058]
Also, a servo pilot signal having a frequency of 80T indicated by oblique lines is recorded on the recording track G of the 12 right tracks, and a servo pilot signal having a frequency of 8T indicated by the blank is recorded on the recording track H. The recording track B is recorded with a servo pilot signal having a frequency of 8T shown in a blank area, and the recording track C is recorded with a servo pilot signal having a frequency of 80T shown in a diagonal line. Subsequently, a servo pilot signal having a frequency of 80T indicated by diagonal lines is recorded on the recording track G, and a servo pilot signal having a frequency of 8T indicated on a plain ground is recorded on the recording track H.
[0059]
Further, one ECC block is configured as follows. FIG. 6 is a diagram illustrating a configuration example of an ECC block according to a product code of the video data Dv. FIG. 7 is a diagram illustrating a configuration example of one sync block of the ECC block. In this example, one field of video data Dv is recorded on each of 12 tracks. At the time of recording and reproduction, four tracks are simultaneously scanned by four heads in one scan, so that 12 tracks are scanned by three scans.
[0060]
One ECC block is configured as follows. That is, for video data having a data array of 226 bytes × 114 bytes shown in FIG. 6, the data (data sequence) of each column is, for example, (126, 114) Reed-Solomon for the outer code operation data sequence indicated by the arrow b. It is encoded by a code to generate a 12-byte C2 parity (outer code parity: OUTER). Further, with respect to the video data and the C2 parity, data (data sequence) of each row is encoded by, for example, a (242, 226) Reed-Solomon code for an inner code operation data sequence indicated by an arrow a in FIG. A byte C1 parity (inner parity: INNER) is generated. At the head of each data line, sync data and ID each having a size of 2 bytes are arranged.
[0061]
The first two bytes shown in FIG. 7 are sync data. The next two bytes are an ID. This ID includes a track ID for identifying which of the 12 tracks the one sync block is recorded on, and which of a plurality of sync blocks recorded on one inclined track is the same as the one sync block. The sync block ID to be identified is included. One segment is formed for every 12 tracks, and segment numbers “0 to 3” are sequentially and repeatedly assigned. The above-mentioned 2-byte ID includes the segment number of the segment in which the one sync block is recorded. The included segment ID is also included. This ID is followed by 226 bytes of video data (or C2 parity) and 16 bytes of C1 parity.
[0062]
8A to 8C show a video data area ARV in 12 tracks constituting one segment. _L , ARV _U FIG. 6 is a diagram showing an example (part 1) of arrangement of sync blocks of each ECC block in FIG. As shown in FIG. 8A, regarding the four tracks “0 to 3” scanned for the first time, the video data area ARV _L Records 21Row sync blocks from 0Row to 20Row in the ECC block of “0 to 35”, and stores the video data area ARV. _U In the ECC block, 21 Row sync blocks from 21 Row to 41 Row in the ECC blocks “0 to 35” are recorded.
[0063]
For the four tracks “4 to 7” scanned for the second time, the video data area ARV _L Records 21Row sync blocks from 42Row to 62Row in the ECC block of “0 to 35”, and stores the video data area ARV. _U , 21Row sync blocks from 63Row to 83Row in the ECC block of 0 to 35 are recorded.
[0064]
Further, regarding the four tracks “8 to 11” scanned for the third time, the video data area ARV _L Records 21Row sync blocks from 84Row to 104Row in the ECC block of “0 to 35”, and stores the video data area ARV. _U In the ECC block, 21 Row sync blocks from 105 Row to 125 Row in the ECC blocks “0 to 35” are recorded.
[0065]
Here, the 0Row sync block includes the 0th sync block in each of the ECC blocks “0 to 35”, and these 36 sync blocks are “0 to 4” as shown in FIG. 8B. ”Are recorded in the track of“ 9 ”in a distributed manner by nine sync blocks. That is, the 0th sync block of the ECC block of “0, 18, 1, 19, 2, 20, 3, 21, 4” is recorded on the track “0”, and the track “22” is recorded on the track “1”. , 5, 23, 6, 24, 7, 25, 8, 26 ”, the 0th sync block is recorded, and“ 9, 27, 10, 28, 11, 29, The 0th sync block in the ECC block of "12, 30, 13" is recorded, and the track of "3" is recorded in the ECC block of "31, 14, 32, 15, 33, 16, 34, 17, 35". The 0th sync block is recorded.
[0066]
Hereinafter, similarly, the sync blocks of 1 to 125 Row are respectively composed of the first to 125th sync blocks in the ECC blocks of “0 to 35”, and each of the 36 sync blocks is 9 in the corresponding four tracks. Sync blocks are sorted and recorded. In this case, for each row, an ECC block from which nine sync blocks recorded on each of four tracks are extracted is rotated. As shown in FIG. 8C, one sync block includes 2-byte sync data, 2-byte ID, 226-byte video data (or C2 parity), and 16-byte C1 parity.
[0067]
Here, sync blocks of 0 Row to 125 Row are sequentially recorded on 12 tracks “0 to 11”. In this case, the sync blocks of 0Row to 113Row are obtained by adding a C1 parity to the data sequence of the video data forming the inner code operation data sequence, while the sync blocks of 114Row to 125Row are the inner code operation data sequence. The C1 parity is added to the data string of the C2 parity constituting the above.
[0068]
FIG. 9 shows a 12-track video data area ARV constituting one segment. _L , ARV _U FIG. 6 is a diagram showing an example (part 2) of arrangement of sync blocks of each ECC block in FIG. In this embodiment, when 36 ECC blocks “0 to 35” are recorded on 12 tracks, as shown in FIG. 9, the data string of the video data constituting the inner code operation data sequence first has C1 A first sync block to which parity is added is sequentially recorded, and after recording of the first sync block is completed, a C1 parity is added to a C2 parity data sequence forming an inner code operation data sequence. The second sync blocks are sequentially recorded.
[0069]
Subsequently, the recording / reproducing operation of the VTR 100 will be described for the recording / reproducing method according to the present invention. FIG. 10 is a graph showing a relationship example between the reproduction level and the off-track amount.
[0070]
In FIG. 10, the vertical axis represents the reproduction output levels of the Cch and Gch reproduction heads, and the horizontal axis represents the off-track amount of each head from a certain reference position. The one-dot chain line shown in FIG. 10 shows the output characteristics at the time of reproducing the servo pilot signal of the frequency of 80T in the Cch reproducing head. In this case, the reproduction output level with respect to the off-track amount is dull so as to smoothly change.
[0071]
The dashed line shown in FIG. 10 is the output characteristic when the Gch reproducing head reproduces the servo pilot signal of the frequency of 80T. Also in this case, the reproduction output level with respect to the off-track amount is dull so as to smoothly change. The solid line shown in FIG. 10 shows the output characteristics at the time of reproducing the servo pilot signal at the frequency of 8T in the Cch and Gch reproducing heads, and shows the characteristics at the time of the just track. In this case, the reproduction output level with respect to the off-track amount is sharpened so as to rise. In this state, the Cch and Gch reproducing heads are pulled into the tracking target position.
[0072]
FIGS. 11A to 11D are timing charts showing examples of detection of reproduction output levels at frequencies of 8T and 80T for the Cch and Gch reproduction heads.
11A to 11D, the horizontal axis represents time t. FIG. 11A shows a switch selection signal (SW'Pulse) Ssw. The head selection switch circuit 43 shown in FIG. 1 selects a Cch reproduction head when the switch selection signal Ssw is at a low level (hereinafter, referred to as “L” level). When the switch selection signal Ssw is at a high level (hereinafter referred to as “H” level), the head selection switch circuit 43 operates so as to select the Gch reproducing head.
[0073]
11B to 11D, the two-dot chain line is the threshold (voltage) Vth set in the detectors 71 and 72. This threshold is used as a detection reference for reproducing output levels at frequencies of 8T and 80T relating to Cch and Gch reproducing heads in order to find just tracking.
[0074]
FIG. 11B shows a detection example at the time of off-tracking of the Cch and Gch reproducing heads. According to the detection example shown in FIG. 11B, for example, when the Gch reproducing head is off-track to the right from the tracking target position (−offtrack), the reproduction output of the Cch reproducing head at a frequency of 80T increases, and the Cch and Gch are output. The reproduction output level of the reproduction head at the frequency of 8T decreases and the reproduction output of the Gch reproduction head at the frequency of 80T decreases.
[0075]
FIG. 11C shows an example of detection at the time of just tracking (Just) of the Cch and Gch reproducing heads. According to the detection example shown in FIG. 11C, the reproduction output level of the Cch and Gch reproduction heads at the frequency of 8T becomes the maximum value, and the reproduction output of the Cch reproduction head at the frequency of 80T and the reproduction output level of the Gch reproduction head at the frequency of 80T Becomes the same level as the reproduction output.
[0076]
FIG. 11D shows another detection example at the time of off-tracking of the Cch and Gch reproducing heads. According to the detection example shown in FIG. 11D, for example, when the Gch reproducing head is off-track to the left of the tracking target position (+ offtrack), the reproduction output of the Gch reproducing head at a frequency of 80T increases, and the Cch and Gch are output. The reproduction output level of the reproduction head at the frequency of 8T decreases and the reproduction output of the Cch reproduction head at the frequency of 80T decreases.
[0077]
Based on these, the operation example of the VTR 100 will be described separately for recording and reproduction.
[0078]
[Recording]
In this example, as shown in FIG. 5B, an 8T frequency servo pilot signal is recorded on one reference recording track (C and G) every time the head scans, and a track adjacent thereto is recorded. Among them, a servo pilot signal having a frequency of 80T is recorded in only one of them, and no pilot is recorded in the other. Then, the recording side of the servo pilot signal of the 80T frequency is switched between the right side and the left side every other scan.
[0079]
Under this operating condition, the recording video signal VSin is input from the video input terminal 110 to the video compression circuit 10 in the VTR 100 shown in FIG. The video compression circuit 11 divides the recording video signal VSin into two-dimensional blocks of 8 × 8 pixels, and performs data compression processing using block coding such as DCT. The recording audio signal ASin is input to the parity adding circuit 20 through the audio input terminal 130. The video data (compression-encoded data) Dv after the compression processing is input to the parity addition circuit 20.
[0080]
The parity adding circuit 20 receives the video data Dv after the compression processing and the recording audio signal ASin, and performs an error correction coding processing on the compression coded data Dv using a product code for each coding unit. At the same time, an error correction encoding process using a product code is performed on the recording audio signal ASin.
[0081]
The video data + audio data VDb after the error correction encoding processing is output from the parity adding circuit 20 to the servo pilot adding unit 30. The servo pilot adder 30 adds a servo pilot signal (CTL signal) having a frequency of 8T and 80T to the video data + audio data VDb subjected to the error correction processing.
[0082]
The video data + audio data VDb to which the servo pilot signal is added is output from the servo pilot adder 30 to four head selection switch circuits 41, 42, 43, 44. The head selection switch circuits 41, 42, 43, and 44 switch the helical recording head 50 having eight recording heads RECA to RECH for the A channel to the H channel in order to execute 180-degree facing recording. Done. The helical recording head 50 records a servo pilot signal on the magnetic tape 80.
[0083]
In this example, a switch selection signal Ssw is supplied from the servo microcomputer 90 to each of the head selection switch circuits 41 to 44, and the head selection switch circuit 43 selects the recording heads RECC and RECG of the C channel and the G channel, At 80, a servo pilot signal having a frequency of 8T is recorded on the reference C and G recording tracks. At the same time, a servo pilot signal having a frequency of 80T is recorded on the adjacent B and H recording tracks, with the right and left sides being switched every other C and G recording tracks.
[0084]
At this time, the head selection switch circuit 41 selects the Ach recording head (RECA) or the Ech recording head (RECE) on a time division basis based on the switch selection signal Ssw, and converts the video data + audio data VDb after the servo pilot signal is added. Output is made to the Ach recording head and the Ech recording head. Further, the head selection switch circuit 42 selects the Bch recording head (RECB) or the Fch recording head (RECF) in a time division manner based on the switch selection signal Ssw, and converts the video data + audio data VDb after the servo pilot signal is added to the Bch recording head. Output is made to the recording head and the Fch recording head.
[0085]
Further, the head selection switch circuit 43 selects the Cch recording head (RECC) or the Gch recording head (RECG) in a time division manner based on the switch selection signal Ssw, and converts the video data + audio data VDb after the servo pilot signal is added to the Cch recording head. Output is made to the recording head and the Gch recording head. The head selection switch circuit 44 selects the Dch recording head (RECD) or the Hch recording head (RECH) in a time division manner based on the switch selection signal Ssw, and converts the video data + audio data VDb after the servo pilot signal is added. Output is made to a Dch recording head or an Hch recording head.
[0086]
As a result, as shown in FIG. 5B, a servo pilot signal having a frequency of 8T is recorded on one reference recording track (C and G) every time the head is scanned, and a track adjacent to this is recorded. The servo pilot signal having the frequency of 80T can be recorded on only one of them, and the servo pilot signal can not be recorded on the other. That is, a servo pilot signal having a frequency of 8T is recorded on the reference recording tracks (C and G) on the magnetic tape 80, and recording is performed on the recording track adjacent to the recording track by exchanging the right and left sides every other track. A servo pilot signal having a frequency of 80T can be recorded on the tracks (B and H).
[0087]
[During playback]
In this example, in tracking at the time of editing or the like, an initial head pull-in is performed using a servo pilot signal having a frequency of 80T. After that, the final pull-in is continuously performed with the servo pilot signal having the frequency of 8T. By doing so, it is possible to achieve both the head pull-in accuracy and the head pull-in speed. In this example, two recording heads RECC and RECG of the C channel and the G channel are also used at the time of pilot reproduction.
[0088]
Under these operating conditions, in the VTR 100 shown in FIG. 1, the recording track of the magnetic tape 80 is traced by the Cch recording head and the Gch recording head, so that the servo pilot signal is read and reproduced. Of course, the magnetic tape 80 is capstan driven so as to move in a predetermined running direction.
[0089]
Also, the head selection switch circuit 43 shown in FIG. 1 is supplied with a switch selection signal Ssw of “L” level and “H” level as shown in FIG. 11A from the servo microcomputer 90. The head selection switch circuit 43 selects a Cch reproducing head when Ssw = “L” level. Further, when Ssw = “H” level, the operation is performed to select the Gch reproducing head.
[0090]
Under such selection control, the servo pilot signals read by the Cch recording head and the Gch recording head are output to the 8T BPF circuit 61 and the 80T BPF circuit 62 through the head selection switch circuit 43. The 8T BPF circuit 61 performs a filtering process for passing only a servo pilot signal of 8T frequency reproduced by the Cch recording head (RECC) or the recording head (RECG). In the 80T BPF circuit 62, filter processing for passing the servo pilot signal of the 80T frequency reproduced in the same manner is performed.
[0091]
The servo pilot signal after this filtering is output from the 8T BPF circuit 61 to the detector 71. The threshold value Vth is set in the detector 71 as shown in FIGS. 11B to 11D, and the detector 71 detects only the servo pilot signal having a frequency of 8T based on the threshold value Vth.
[0092]
Further, the servo pilot signal after the filter processing is output from the 80T BPF circuit 62 to the detector 72. The threshold value Vth is similarly set in the detector 72, and the detector 72 detects only the servo pilot signal having the frequency of 80T based on the threshold value Vth.
[0093]
The reproduced output levels of the servo pilot signals having the frequencies of 8T and 80T detected by the detectors 71 and 72 are output to the servo microcomputer 90. In the servo microcomputer 90, an initial head pull-in operation based on a servo pilot signal of a frequency of 80T reproduced from the recording track by the Cch recording head and the Gch recording head is performed. Head retraction is performed.
[0094]
For example, as shown in FIG. 11B, when the Gch reproducing head is off-track to the right from the tracking target position (-offtrack), the trace position is adjusted so that the Gch reproducing head is shifted to the left. At this time, the reproduction output of the Cch reproduction head at the frequency of 80T increases, the reproduction output level of the Cch and Gch reproduction head at the frequency of 8T decreases, and the reproduction output of the Gch reproduction head at the frequency of 80T decreases. I do.
[0095]
Also, as shown in FIG. 11D, for example, when the Gch reproducing head is off-track to the left of the tracking target position (+ offtrack), the trace position is adjusted so that the Gch reproducing head is shifted to the right. For this adjustment, capstan drive control, dynamic tracking control, and the like are performed. By this adjustment, the reproduction output of the Gch reproducing head at the frequency of 80T changes from increasing to decreasing, the reproducing output level of the Cch and Gch reproducing head at the frequency of 8T changes from decreasing to increasing, and furthermore, the reproduction output level of the Cch reproducing head changes. The reproduction output at the frequency of 80T starts to decrease and then increases.
[0096]
Then, as shown in FIG. 11C, just-tracking (Just) of the Cch and Gch reproducing heads is performed. At this time, the reproduction output level of the Cch and Gch reproduction heads at the frequency of 8T becomes the maximum value, and the reproduction output of the Cch reproduction head at the frequency of 80T is equal to the reproduction output of the Gch reproduction head at the frequency of 80T. Become a level.
[0097]
As described above, according to the VTR 100 and the recording / reproducing method according to the embodiment of the present invention, the video data + audio data VDb is recorded on the magnetic tape 80 and / or the video data + audio data VDc is read from the magnetic tape 80. In the case of reproducing the data, the recording / reproducing means 4 alternates the right and left sides alternately with respect to the recording track of the magnetic tape 80 previously recorded and alternately replaces the adjacent recording tracks (B and H). A servo pilot signal having a frequency of 80T is reproduced, and a servo pilot signal having a frequency of 8T is reproduced from a reference recording track (C and G).
[0098]
Accordingly, it is possible to execute the head pull-in based on the servo control signal of the first frequency following the initial head pull-in based on the servo control signal of the second frequency reproduced from the recording track. This makes it possible to cause the reproducing head and the like to converge on the reference recording tracks (C and G) at high speed, accurately, and reliably. In addition, in a recording / reproducing system in which the S / N for timing detection is not sufficient in the conventional method, or in a recording format having a relatively large initial off-track and a narrow pitch, the tracking pull-in process can be performed with high accuracy and high speed. It is possible to achieve both.
[0099]
【The invention's effect】
As described above, according to the recording / reproducing apparatus of the present invention, when digital information is recorded on an information recording medium and / or when digital information is reproduced from the information recording medium, The right and left sides are alternately replaced every other recording track, and the second frequency servo control signal is reproduced from the adjacent recording track, and the first frequency servo control signal is reproduced from the reference recording track. And a reproducing means for performing the operation.
[0100]
With this configuration, it is possible to execute the head pull-in based on the servo control signal of the first frequency following the initial head pull-in based on the servo control signal of the second frequency reproduced from the recording track. Accordingly, it is possible to cause the reproducing head and the like to converge on the reference recording track at high speed, accurately, and reliably. In addition, in a recording / reproducing system in which the SN is not sufficient for timing detection in the conventional method, or in a format having a relatively large initial off-track and a narrow pitch, it is possible to achieve both high precision and high speed in the head pull-in process. Can be achieved.
[0101]
According to the recording / reproducing method according to the present invention, at the time of information recording, a servo control signal of the first frequency is recorded on a reference recording track on the information recording medium, and every other right and left sides of the recording track are recorded. Are alternately recorded on the adjacent recording track to record the servo control signal of the second frequency, and at the time of information reproduction, the information recording medium alternately alternates the right and left sides of the recording track with every other recording track. The servo control signal of the second frequency is reproduced from the recorded recording track to execute the initial head pull-in of the recording / reproducing system, and the servo control signal of the first frequency is reproduced from the reference recording track following the initial head pull-in. Then, the head of the recording / reproducing system is pulled in.
[0102]
With this configuration, it is possible to quickly, accurately, and surely converge on the recording track based on the recording / reproducing system. In addition, in a recording / reproducing system in which the SN is not sufficient for timing detection in the conventional method, or in a format having a relatively large initial off-track and a narrow pitch, it is possible to achieve both high precision and high speed in the head pull-in process. Can be achieved.
[0103]
INDUSTRIAL APPLICABILITY The present invention is very suitably applied to home and business video recording / reproducing apparatuses for reproducing digital information from a tape recording medium.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration example of a VTR 100 to which a recording / reproducing device as an embodiment according to the present invention is applied.
FIG. 2 is a block diagram showing an example of the internal configuration of a parity adding circuit 20.
FIG. 3 is a conceptual diagram showing a configuration example of a rotary drum 140 according to the VTR 100 shown in FIG.
FIG. 4 is a diagram showing an example of a recording format on a magnetic tape 80.
FIGS. 5A and 5B are diagrams showing examples of a VTR format in which a video sync (M) and an audio sync (N) are mixed.
FIG. 6 is a diagram illustrating a configuration example of an ECC block according to a product code of video data Dv.
FIG. 7 is a diagram illustrating a configuration example of one sync block of an ECC block.
FIGS. 8A to 8C show video data areas ARV in 12 tracks forming one segment. _L , ARV _U FIG. 6 is a diagram showing an example (part 1) of arrangement of one sync block of each ECC block in FIG.
FIG. 9 shows a 12-track video data area ARV constituting one segment. _L , ARV _U FIG. 10 is a diagram showing an example (No. 2) of arrangement of one sync block of each ECC block in FIG.
FIG. 10 is a graph showing an example of a relationship between a reproduction level and an off-track amount.
FIGS. 11A to 11D are timing charts showing examples of detection of reproduction output levels at frequencies of 8T and 80T relating to Cch and Gch reproduction heads.
[Explanation of symbols]
4 ... Recording / reproducing means, 10 ... Video compression circuit, 20 ... Parity addition circuit, 30 ... Servo pilot addition device, 41-44 ... Head selection switch circuit, 50, RECA-RECH. ..Helical recording head, 61 ... 8T BPF circuit, 62 ... 80T BPF circuit, 71,72 ... detector, 80 ... magnetic tape (information recording medium), 90 ... servo Microcomputer (control means), 100 VTR (information recording / reproducing device), helical recording head

Claims (5)

An apparatus that records digital information on an information recording medium and / or reproduces digital information from the information recording medium,
A servo control signal of a first frequency is recorded on a reference recording track on the information recording medium, and the right and left sides of the recording track are alternately replaced with the right and left sides alternately, and a second frequency servo control signal is recorded on an adjacent recording track. Recording means for recording a servo control signal;
The right and left sides of the recording track of the information recording medium recorded by the recording means are alternately replaced alternately on the right and left sides to reproduce the servo control signal of the second frequency from the adjacent recording track, And a reproducing means for reproducing a servo control signal of the first frequency from the recording track. A control unit for executing a head pull-in operation based on the servo control signal of the first frequency following the initial head pull-in operation based on the servo control signal of the second frequency reproduced from the recording track by the reproducing unit. The recording / reproducing apparatus according to claim 1. The recording / reproducing apparatus according to claim 1, wherein the second frequency of the servo control signal is set lower than the first frequency. A method of recording digital information on an information recording medium and / or reproducing digital information from the information recording medium,
When recording the digital information,
The first frequency servo control signal is recorded on a reference recording track on the information recording medium, and the second frequency servo control is performed on an adjacent recording track by switching the right and left sides of the recording track every other track. Record the signal,
When reproducing the digital information,
On the information recording medium, the right and left sides of the recording track are alternately alternately alternately reproduced, and the servo control signal of the second frequency is reproduced from the adjacent recording track to execute the initial head pull-in of the recording / reproducing system. ,
A recording / reproducing method characterized by reproducing a servo control signal of a first frequency from a reference recording track continuously with the initial head pull-in and executing the head pull-in of the recording / reproducing system. The method according to claim 4, wherein the second frequency of the servo control signal is set lower than the first frequency.

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