JP3925175B2 - Image reproducing apparatus and method, recording medium, and program - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reproducing apparatus and method, a recording medium, and a program, and in particular, an image reproducing apparatus and method capable of stably reproducing an image signal recorded on a tape-shaped recording medium even during variable speed reproduction, The present invention relates to a recording medium and a program.
[0002]
[Prior art]
In a digital video tape recorder, an image signal is compressed by, for example, an MPEG (Moving Picture Experts Group) method and recorded on a magnetic tape. FIG. 1 shows an example in which 15 frames are set as GOP (Group of Picture) out of stream data of an image signal and the image signal is compressed by the MPEG method. 1A shows an original image signal in which image signals are arranged in time series, and Nos. 0 to 14 indicate the numbers of the respective frames of the image signal.
[0003]
In FIG. 1B, the image signal A of FIG. 1A is represented by the MPEG system as three types of pictures: an I picture (Intra Coded Picture), a P picture (Predictive Coded Picture), and a B picture (Bidirectionally Coded Picture). A compressed image signal is shown. The numbers on the lower right of each of I, P, and B in the image signal B indicate the frame numbers of the original image signal A.
[0004]
An I picture is an image signal compressed only with an image signal in a frame. That is, for example, the I picture I2 of the image signal B located in the leftmost column in FIG. 1 is an image signal obtained by compressing only the image signal of the frame No. 2 of the image signal A.
[0005]
A P picture is an image signal compressed using an image signal of a past I picture or P picture in time in addition to an image signal in a frame. That is, for example, the P picture P5 of the image signal B is an image signal compressed using the image signal of the frame No. 5 and the image signal of the previous I picture I2.
[0006]
A B picture is an image signal compressed by using image signals of temporally preceding and following I pictures and P pictures in addition to image signals in a frame. That is, for example, the B picture B0 of the image signal B uses the image signal of the frame No. 0, the I picture I2 that is earlier in time, and the image signal of the P picture P5 that is later than that in time. The compressed image signal.
[0007]
As described above, since the I picture is compressed from the image signal of a single frame, the decompression process can be performed only from the I picture. On the other hand, the P picture and B picture decompression process requires one or both of the preceding and subsequent I pictures and P pictures, so that the decompression process alone cannot be performed. .
[0008]
Thus, after the image signal A in FIG. 1 is compressed as indicated by the image signal B, the image signal is recorded on the magnetic tape and read out in the order recorded by the magnetic head.
[0009]
By the way, when an image signal compressed by the MPEG method is played back on a magnetic tape at a variable speed, the magnetic head reads the image signal across a plurality of tracks having different azimuth angles, so the reproduced image signal is intermittent. Signal. For this reason, if an image signal such as the above-mentioned P picture or B picture, which cannot be expanded independently, is intermittently read from the magnetic head, the image cannot be reproduced because there is no image to be referred to. Become.
[0010]
That is, as shown in FIG. 2, the two rotary heads 1a and 1b are mounted at positions symmetrical with respect to the central axis of the drum 1 with a predetermined azimuth angle (in FIG. 2, the rotary head 1a). Is a positive azimuth angle, and the rotary head 1b is a negative azimuth angle). Also, as shown in FIG. 3, on the magnetic tape 2, each band-like track (the number given to each band-like portion indicates the track number, and + and- In this case, the track is recorded / reproduced by the rotary head 1a having an azimuth angle of +, and in the case of-, the track is recorded / reproduced by the rotary head 1b having an azimuth angle of −. Is recorded. The rotary heads 1a and 1b are so-called magnetic heads, and during normal reproduction, tracks corresponding to the azimuth of each track are sequentially reproduced. Since the speed is higher than that at the time of reproduction, in the case of the rotary head 1b shown in FIG. 3 with the azimuth angle being minus, it moves in the direction of the arrow shown in FIG.
[0011]
At this time, the rotary head 1b detects the signal recorded on the magnetic tape 2 across the signal with the azimuth angle added in the + direction and the signal attached in the-direction alternately. For this reason, the RF (Radio Frequency) signal detected by the rotary head 1b is a signal as shown in FIG.
[0012]
Assuming that, for example, a signal that is reduced by about 6 dB among RF signals as shown in FIG. 4A can be reproduced as data, the reproduced data signal is intermittent as shown in FIG. 4B. Signal. Therefore, at the time of variable speed reproduction, the B picture and P picture are in a state in which information necessary for the expansion process cannot always be read out.
[0013]
Therefore, at the time of variable speed reproduction, only the image signal of the I picture is arranged at a predetermined position on the magnetic tape as the image signal for variable speed reproduction, and the magnetic head is controlled to read out only the I picture continuously. , Variable speed playback is made. At this time, the video tape recorder detects the rotation period of the capstan motor that travels the magnetic tape, finds a deviation (speed error) between the detected rotation period and a pre-stored reference period, and detects this speed error. Thus, the rotational speed of the capstan motor is controlled so that the magnetic head detects only the image signal of the I picture on the magnetic tape.
[0014]
[Problems to be solved by the invention]
However, in the configuration as described above, the rotational speed of the capstan motor can be controlled when performing variable speed reproduction. For example, when a slip occurs between the capstan motor and the magnetic tape, When expansion or contraction occurs in the magnetic tape, it is impossible to detect a speed difference between the capstan motor and the magnetic tape. For this reason, the scan position of the magnetic head and the position where the I picture on the magnetic tape is recorded cannot be exactly matched, so that a part of the reproduced image is lost or the image update rate is deteriorated. There was a problem such as.
[0015]
In order to solve these problems, in the invention of Japanese Patent Application No. 2000-171576, the position where the I picture is recorded on the magnetic tape is stored in units of sync block numbers on a predetermined track, and the read data is stored. It is considered that the running state of the magnetic tape is detected and the I picture is read out by comparing with the sync block number. However, in this configuration, since control is performed in units of sync blocks, there is a problem that it takes a processing time to stabilize the running state of the magnetic tape.
[0016]
The present invention has been made in view of such a situation, and enables an image signal recorded on a tape-shaped recording medium to be stably reproduced even during variable speed reproduction and to achieve a stable reproduction state. The processing time can be shortened.
[0017]
[Means for Solving the Problems]
  The image reproducing apparatus of the present invention stores, as a target position, the position of a track on a tape-shaped recording medium in which information for variable speed reproduction exists among image information.At the same time, the position of the sync block on the tape-shaped recording medium where the image information for variable speed reproduction is included is further stored as the target position.Information on the track in the vicinity where the target position storage means and the image information for variable speed playback recorded on the tape-shaped recording medium existAs data block unit information consisting of a plurality of sync blocks continuous for a predetermined number or moreThe reading means to read and the track position of the information read by the reading means are detected.At the same time, the position of the sync block of the information read by the reading means is further detected.Stored by position detection means and target position storage meansTruckTarget position and detected by position detection meansTruckCompare with positionIn addition, the sync block target position stored in the target position storage means is compared with the sync block position detected by the position detection means.By comparison means and comparison meansPer trackBased on the comparison result, the feeding speed of the tape-shaped recording medium is controlled in units of tracks.At the same time, with the control in units of tracks being completed, the feeding speed of the tape-shaped recording medium is further controlled in units of sync blocks based on the comparison result of the sync blocks.Feed speed control means;Sync block interpolation means for interpolating non-continuous sync blocks when the number of non-continuous sync blocks is less than or equal to a predetermined number of sync blocks constituting a data block;It is characterized by providing.
[0019]
The reading means reads information on a track in the vicinity where one piece of image information for variable speed reproduction exists among a plurality of pieces of image information for variable speed reproduction recorded on the tape-shaped recording medium. can do.
[0020]
  Reading means includeWhen control is performed in units of sync blocks, a track in the vicinity where there is one other image information for variable speed reproduction that is different from one image information for variable speed reproduction recorded on the tape-shaped recording medium. The above information can be read.
[0021]
  The image reproduction method of the present invention stores the position of a track on a tape-shaped recording medium in which information for variable speed reproduction exists among image information as a target position.At the same time, the position of the sync block on the tape-shaped recording medium where the image information for variable speed reproduction is included is further stored as the target position.The target position storing step and the information on the track in the vicinity where the image information for variable speed playback recorded on the tape-shaped recording medium exists are stored.As data block unit information consisting of a plurality of sync blocks continuous for a predetermined number or moreDetects the reading step to be read and the track position of the information read in the reading step process.At the same time, the position of the sync block of the information read by the processing of the reading step is further detected.Stored in the processing of the position detection step and the target position storage stepTruckDetected by target position and position detection step processingTruckCompare with positionAt the same time, the sync block target position stored in the target position storing step is compared with the sync block position detected in the position detecting step.In the comparison step and the processing of the comparison stepOf track unitsBased on the comparison result, the feeding speed of the tape-shaped recording medium is controlled in units of tracks.At the same time, with the control in units of tracks being completed, the feeding speed of the tape-shaped recording medium is further controlled in units of sync blocks based on the comparison result of the sync blocks.A feed rate control step;A sync block interpolation step for interpolating non-continuous sync blocks when the number of non-continuous sync blocks is less than or equal to a predetermined number of sync blocks constituting a data block;It is characterized by including.
In the process of the reading step, information on a track in the vicinity where one piece of image information for variable speed reproduction exists among plural pieces of image information for variable speed reproduction recorded on the tape-shaped recording medium is read. Can be.
In the processing of the reading step, when control is performed in units of sync blocks, the image information for one variable speed reproduction, which is different from one image information for variable speed reproduction recorded on the tape-shaped recording medium, is used. The information on a track in the vicinity where image information exists can be read.
[0022]
  The recording medium program of the present invention controls storage as a target position of a track position on a tape-shaped recording medium in which information for variable speed reproduction exists among image information.At the same time, it further controls the storage of the position of the sync block on the tape-shaped recording medium on which the image information for variable speed reproduction exists among the image information as the target positionThe target position storage control step and the information on the track in the vicinity where the image information for variable speed playback recorded on the tape-shaped recording medium existsAs data block unit information consisting of a plurality of sync blocks that are continuous for a predetermined number or moreControls the reading control step that controls reading and the detection of the track position of the information read in the processing of the reading control stepAt the same time, it further controls the detection of the sync block position of the information read by the processing of the read control step.Storage is controlled by the processing of the position detection control step and the target position storage control step.TruckDetection was controlled by target position and position detection control step processingTruckControls comparison with positionAt the same time, it controls the comparison between the sync block target position stored by the target position storage control step processing and the sync block position detected by the position detection control step processing.In the comparison control step and the comparison control step processingOf track unitsBased on the comparison result, the feeding speed of the tape-shaped recording medium is controlled in units of tracks.At the same time, with the control in units of tracks completed, the feeding speed of the tape-shaped recording medium is controlled in units of sync blocks based on the sync block comparison results.A feed rate control step;A sync block interpolation control step for controlling interpolation of non-continuous sync blocks when the number of non-continuous sync blocks is less than or equal to a predetermined number of sync blocks constituting a data block;It is characterized by including.
In the process of the reading control step, information on a track in the vicinity where one piece of image information for variable speed reproduction out of a plurality of pieces of image information for variable speed reproduction recorded on the tape-shaped recording medium exists is read. Can be controlled.
In the process of the reading control step, when control is performed in units of sync blocks, the image information for one variable speed reproduction that is different from one image information for variable speed reproduction recorded on the tape-like recording medium is used. It is possible to control reading of information on a track in the vicinity where the image information exists.
[0023]
  The program of the present invention controls the storage of the position of the track on the tape-shaped recording medium in which information for variable speed reproduction exists among the image information as the target position.At the same time, it further controls the storage of the position of the sync block on the tape-shaped recording medium on which the image information for variable speed reproduction exists among the image information as the target positionThe target position storage control step and the information on the track in the vicinity where the image information for variable speed playback recorded on the tape-shaped recording medium existsAs data block unit information consisting of a plurality of sync blocks that are continuous for a predetermined number or moreControls the reading control step that controls reading and the detection of the track position of the information read in the processing of the reading control stepAt the same time, it further controls the detection of the sync block position of the information read by the processing of the read control step.Storage is controlled by the processing of the position detection control step and the target position storage control step.TruckDetection was controlled by target position and position detection control step processingTruckControls comparison with positionAt the same time, it controls the comparison between the sync block target position stored by the target position storage control step processing and the sync block position detected by the position detection control step processing.In the comparison control step and the comparison control step processingOf track unitsBased on the comparison result, the feeding speed of the tape-shaped recording medium is controlled in units of tracks.At the same time, with the control in units of tracks completed, the feeding speed of the tape-shaped recording medium is controlled in units of sync blocks based on the sync block comparison results.A feed rate control step;A sync block interpolation control step for controlling interpolation of non-continuous sync blocks when the number of non-continuous sync blocks is less than or equal to a predetermined number of sync blocks constituting a data block;Is executed by a computer.
In the process of the reading control step, information on a track in the vicinity where one piece of image information for variable speed reproduction out of a plurality of pieces of image information for variable speed reproduction recorded on the tape-shaped recording medium exists is read. Can be controlled.
In the process of the reading control step, when control is performed in units of sync blocks, the image information for one variable speed reproduction that is different from one image information for variable speed reproduction recorded on the tape-like recording medium is used. It is possible to control reading of information on a track in the vicinity where the image information exists.
[0024]
  In the image reproducing apparatus and method and the program of the present invention, the position of the track on the tape-shaped recording medium in which the information for variable speed reproduction exists is stored as the target position among the image information.In addition, among the image information, the position of the sync block on the tape-shaped recording medium where the image information for variable speed reproduction exists is further stored as the target position.The information on the track in the vicinity where the image information for variable speed reproduction recorded on the tape-shaped recording medium exists is read, and the position of the track of the read information isAs data block unit information consisting of a plurality of sync blocks continuous for a predetermined number or moreDetectedThe sync block position of the read information is further detected.,TruckTarget position and detectedTruckCompared to the positionAt the same time, the stored sync block target position is compared with the detected sync block position.,Per trackBased on the comparison result, the feeding speed of the tape-shaped recording medium is controlled in track units.At the same time, with the control in units of tracks completed, the feeding speed of the tape-shaped recording medium is further controlled in units of sync blocks based on the sync block comparison results.,Of the sync blocks constituting the data block, when the number of non-continuous sync blocks is less than or equal to the predetermined number, the non-continuous sync blocks are interpolated.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
5 and 6 are diagrams showing the configuration of an embodiment of a digital video tape recorder according to the present invention. FIG. 5 mainly shows the configuration of the image signal recording system, and FIG. 6 mainly shows the configuration of the reproduction system.
[0026]
First, the configuration of the recording system in FIG. 5 will be described.
[0027]
The A / D (Analog / Digital) converter 11 converts the input image signal from an analog signal to a digital signal, and outputs it to the compression processing unit 12. The compression processing unit 12 performs DCT (Discrete Cosine Transformation) conversion on the image signal converted into the digital signal input from the A / D converter 11, and then compresses the image signal using the MPEG method as described above, thereby performing variable speed reproduction data. The data is output to the generation unit 13 and the data multiplexing unit 14.
[0028]
The variable speed reproduction data generation unit 13 generates an image signal for variable speed reproduction using only an I picture that can be decompressed independently from the compressed image signal input from the compression processing unit 12, The data is output to the data multiplexing unit 14.
[0029]
The data multiplexing unit 14 multiplexes the image signal input from the compression processing unit 12 or the variable speed reproduction data generation unit 13 with audio, subcode, other system data, and the like as a multiplexed signal. The data is output to the error correction code adding unit 15.
[0030]
The error correction code adding unit 15 adds an error correction code to the multiplexed signal input from the data multiplexing unit 14 and outputs the multiplexed signal to a SYNC / ID (Synchronized Signal / Identified Number) adding unit 16. The SYNC / ID adding unit 16 adds a synchronization signal (sync) and ID to the input signal (sync block) and outputs the signal to the recording amplifier 17. The ID includes a Synchronized Block Number (hereinafter abbreviated as SB No.) composed of a number indicating the number of sync blocks in the track, and the track number (Track Number) on which the signal is recorded. : Hereinafter abbreviated as Tr No.). In general, digital signals are recorded in units of sync blocks (hereinafter referred to as SB). For this reason, the ID including this SB No. and Tr No. is used as an address for writing to the buffer memory.
[0031]
The recording amplifier 17 amplifies the signal input from the SYNC / ID adding unit 16 and outputs the amplified signal to the rotary head 18. The rotary head 18 records the signal input from the recording amplifier 17 on the magnetic tape 35 (FIG. 6).
[0032]
Next, the configuration of the image signal reproduction system will be described with reference to FIG.
[0033]
The rotary head 18 reads a signal recorded on the magnetic tape 35 and outputs it to the reproduction amplifier 21. The reproduction amplifier 21 amplifies the signal input from the rotary head 18 and outputs the amplified signal to the SYNC / ID detection unit 22.
[0034]
The SYNC / ID detection unit 22 receives the SYNC / ID detection request data supplied from the latch data generation unit 62 (FIG. 7) of the microcomputer 31, and among the signals (sync blocks) input from the reproduction amplifier 21, SB corresponding to SYNC / ID detection request data is detected, Tr No. and SB No. are read from the ID, stored in the register for each block, and then output to microcomputer 31 as SYNC / ID detection data At the same time, the image signal is output to the error correction unit 23. SYNC / ID detection request data and SYNC / ID detection data will be described later with reference to FIGS. For example, the Tr No. may be recorded in units of two track pairs corresponding to + and − azimuth angles. In this case, Trp (Track Pair) is used instead of the Tr No. No. may be used, and the two tracks may be identified by + and − of the azimuth angle. In the following description, an example in which Trp No. is used instead of Tr No. will be described.
[0035]
The error correction unit 23 performs error correction processing on the signal input from the SYNC / ID detection unit 22 and outputs the signal subjected to error correction processing to the data separation processing unit 24 during normal reproduction. At the time of variable speed reproduction, the error correction unit 23 outputs the error corrected signal to the variable speed reproduction memory 25.
[0036]
The data separation processing unit 24 separates the voice, subcode, and other system data included in the input signal, outputs the voice to a processing circuit (not shown), and subcodes the system data. Output to computer 31 (no connection). The image signal is output to the terminal 26 a of the switch 27. During normal reproduction, the switch 27 is controlled to be connected to the terminal 26a. Accordingly, at this time, the data separation processing unit 24 outputs the image signal to the decompression processing unit 28.
[0037]
The variable speed reproduction memory 25 is a buffer memory used at the time of variable speed reproduction, temporarily stores the image signal for variable speed reproduction input from the error correction unit 23, and then reads out and outputs it to the terminal 26b of the switch 27. To do. The variable speed reproduction memory 25 temporarily stores an input image signal and reads it out in a frame cycle, and reads out every time an image signal of one frame is stored. Although there is a thing, any type may be sufficient.
[0038]
Further, during variable speed reproduction, the switch 27 is controlled so as to be connected to the terminal 26b. Accordingly, at this time, the variable speed reproduction memory 25 reads out the image signal for variable speed reproduction and outputs it to the expansion processing unit 28 via the switch 27.
[0039]
The decompression processing unit 28 decompresses the image signal compressed by the MPEG method, which is input via the switch 27, performs inverse DCT conversion, and outputs it to a D / A (Digital / Analog) converter 29. . The D / A converter 29 converts the input image signal from a digital signal to an analog signal and outputs the original image signal.
[0040]
The microcomputer 31 is a capstan that drives a capstan that transports the magnetic tape 35 based on various signals input from the SYNC / ID detector 22, the capstan motor rotation detector 33, and the head switching pulse generator 38. A PWM (Pulse Width Modulation) signal for controlling the rotation speed of the motor 34 is generated and output to the driver 32. The driver 32 controls the rotation of the capstan motor 34 based on the PWM signal input from the microcomputer 31.
[0041]
The head switching pulse generation unit 38 is based on the rotation signal of the drum 36 detected by the drum rotation detection unit 37, and the two rotation heads 18 provided in the drum 36 (with azimuth angles of + and −). Among them, a pulse indicating which rotary head 18 is currently reading the image signal is generated and output to the microcomputer 31.
[0042]
Details of the configuration and operation of the microcomputer 31, the driver 32, the rotation detection unit 33, the capstan motor 34, and the head switching pulse generation unit 38 will be described later.
[0043]
Next, the recording operation of the recording system of FIG. 5 will be described. The A / D converter 11 converts the input image signal from an analog signal to a digital signal and outputs the converted signal to the compression processing unit 12. The compression processing unit 12 performs DCT conversion on the image signal input from the A / D converter 11, performs compression processing by the MPEG method, and outputs the result to the variable speed reproduction data generation unit 13 and the data multiplexing unit 14. .
[0044]
The variable speed reproduction data generation unit 13 generates variable speed reproduction data (I picture data) from the compressed image signal input from the compression processing unit 12 and outputs the data to the data multiplexing unit 14. The data multiplexing unit 14 multiplexes audio, subcode, and other system data on the image signal input from the compression processing unit 12 and the variable speed reproduction data generation unit 13 to correct errors as a multiplexed signal. The data is output to the code adding unit 15. The error correction code addition unit 15 adds an error correction code to the multiplexed signal input from the data multiplexing unit 14 and outputs the multiplexed signal to the SYNC / ID addition unit 16.
[0045]
The SYNC / ID addition unit 16 adds a synchronization signal and ID to the signal input from the error correction code addition unit 15 in units of sync blocks, and outputs the result to the recording amplifier 17. The recording amplifier 17 amplifies the signal input from the SYNC / ID adding unit 16 and outputs the amplified signal to the rotary head 18. The rotary head 18 records the image signal input from the recording amplifier 17 on the magnetic tape 35 (FIG. 6).
[0046]
Next, an operation during reproduction of the reproduction system of FIG. 6 will be described. The rotary head 18 reads an image signal recorded on the magnetic tape 35 and outputs it to the reproduction amplifier 21. The reproduction amplifier 21 amplifies the signal input from the rotary head 18 and outputs the amplified signal to the SYNC / ID detection unit 22. The SYNC / ID detection unit 22 receives the SYNC / ID detection request data supplied from the latch data generation unit 62 (FIG. 7) of the microcomputer 31, and receives the read signal (sync block) input from the reproduction amplifier 21. Among these, the Trp No. and SB No. corresponding to the SYNC / ID detection request data are detected and output to the microcomputer 31 and the image signal is output to the error correction unit 23.
[0047]
The error correction unit 23 performs error correction processing based on the error correction code added to the image signal input from the SYNC / ID detection unit 22, and in normal reproduction, the data separation processing unit 24 performs variable speed reproduction. In this case, the data is output to the variable speed reproduction memory 25. In the case of normal reproduction, the data separation processing unit 24 separates the sound from the input multiplexed signal, outputs it to a decoder (not shown), separates the subcode and other system data, and sends it to the microcomputer 31. Then, the image signal is separated and output to the terminal 26a of the switch 27. In the case of the variable speed reproduction, the variable speed reproduction memory 25 temporarily stores the image signal for variable speed reproduction input from the error correction unit 23, and then reads out the image signal to be reproduced sequentially and outputs it to the terminal 26b of the switch 27. To do.
[0048]
The switch 27 is connected to the terminal 26a for normal reproduction and to the terminal 26b for variable speed reproduction. In normal reproduction, the decompression processing unit 28 decompresses the image signal input from the data separation processing unit 24 via the terminal 26a and the switch 27 in the MPEG format, and then performs inverse DCT conversion to perform D / A conversion. Output to the unit 29. In the case of variable speed reproduction, the expansion processing unit 28 extends the image signal for variable speed reproduction input from the variable speed reproduction memory 25 via the terminal 26b and the switch 27, and then performs inverse DCT conversion. Output to the D / A converter 29. The D / A converter 29 converts the image signal input from the decompression processing unit 28 from a digital signal to an analog signal, and outputs it to a television receiver (not shown) to display an image.
[0049]
The microcomputer 31 includes the Trp No. and SB No. included in the SYNC / ID detection data input from the SYNC / ID detection unit 22, and the capstan motor rotation input from the capstan motor rotation detection unit 33. Based on the detection pulse, a PWM signal for controlling the rotation of the capstan motor 34 is generated and output to the driver 32. The driver 32 controls the rotation of the capstan motor 34 based on the input PWM signal.
[0050]
Next, the details of the microcomputer 31, the driver 32, the capstan rotation detection unit 33, the capstan motor 34, and the head switching pulse generation unit 38 will be described with reference to FIG.
[0051]
The SYNC / ID detection unit 22 detects the SB No. and Trp No. of the image signal input from the reproduction amplifier 21 corresponding to the SYNC / ID detection request data supplied from the latch data generation unit 62 of the microcomputer 31. And output to the latch data generation unit 62 as SYNC / ID detection data.
[0052]
A CPU (Central Processing Unit) 61 of the microcomputer 31 controls the overall operation of the microcomputer 31, and in the arithmetic processing, a cap stored in a ROM (Read Only Memory) 202 connected to the bus 201. The contents (program) of the stun servo calculation unit 71 are read and executed. Further, the CPU 61 reads various programs stored in an HDD (Hard Disk Drive) 204 into the RAM 203 or directly executes them as necessary. Further, the CPU 61 reads and executes programs stored in the magnetic disk 211, the optical disk 212, the magneto-optical disk 213, and the semiconductor memory 214 mounted on the drive 205 as necessary.
[0053]
The latch data generation unit 62 detects the SYNC / ID as the SYNC / ID detection request data (FIG. 8) using the data required for controlling the rotation of the capstan motor 32 during the variable speed reproduction by the driver 32. The SYNC / ID detection data (FIG. 9) corresponding to the SYNC / ID detection request data is received from the SYNC / ID detection unit 22, and latch data is generated based on the SYNC / ID detection data (FIG. 9). To the unit 71. Further, the latch data generation unit 62 obtains an average value of the latch data (stores it by itself), and the SYNC / ID detection data corresponding to the SYNC / ID detection request data is not complete (data is insufficient). If there is, the average value is used to generate latch data. The average value may be a predetermined fixed value.
[0054]
As shown in FIG. 8, the SYNC / ID detection request data is composed of a total of 16 bits of data. In the upper 8 bits of the figure, SB No. A indicating the data acquisition start position is displayed as the data acquisition range. In the lower 5 bits (0 to 4 bits) in the lower part of the figure, continuous data N (continuous SB number −1) that specifies the number of consecutive SBs of the data block to be detected is the upper 2 bits (6, 6 in the lower part of the figure). 7bit) records interpolation data M (interpolation SB number −1) indicating the number of SBs that can be interpolated when a loss occurs among consecutive SBs as a data block. Here, the data block indicates a block of SBs composed of continuous SBs, for example, a part from the rising edge to the falling edge shown in FIG. 4B.
[0055]
The data acquisition range (SB No. A) is information indicating the data acquisition start position by the SYNC / ID detector 22, and the A-th time after the head switching pulse rises, that is, the rotary head 18 starts reading data. This is information requesting to start detection from the SB. Specifically, SB No. A designates a position before the SB (SB in which I picture data necessary for variable speed reproduction is recorded) to be detected by the SYNC / ID detector 22; The designation of this position indicates that the SBs prior to SB No. A need not be substantially read out. The latch data generation unit 62 also supplies the head switching pulse supplied from the head switching pulse generation unit 38 to the SYNC / ID detection unit 22. The value of SB No. A varies depending on how many times the speed reproduction processing is performed.
[0056]
The continuous data N is information for designating the number of continuous SBs as a constituent requirement of the data block to be read by the rotary head (magnetic head) 18 on one track, and N is a value obtained by subtracting 1 from the number of continuous SBs. It is the data shown. Since the latch data generation unit 62 generates latch data from three data blocks composed of SBs that are continuously detected after the above SB No. A, the SYNC / ID detection unit 22 is continuously detected. It is determined whether or not a data block is formed by comparing the number of SBs and the value of the continuous data N.
[0057]
Interpolation data M is data indicating the number of SBs that can be interpolated when SB loss (SB that could not be detected) occurs in the above-described data block. It is the added value. The fifth bit in the lower part of the figure (the sixth bit when the right side in the figure is the head) is a reserved area.
[0058]
Next, SYNC / ID detection data will be described with reference to FIG. The SYNC / ID detection data is output from the SYNC / ID detection unit 22 to the microcomputer 31 corresponding to the SYNC / ID detection request data shown in FIG. SYNC / ID detection data is the first data block (in this case, indicated as Block 0: SB No.A starts detection of SB after starting 16 bits from the top row in the figure). Information on the first position of the block, information on the last position, and the second data block (in this case, indicated as Block1: SB No.A starts detection of SB and is the second data block detected ) Start position information, end position information, and third data block (in this case, indicated as Block 2: SB No.A starts detection of SB, and data is detected third. Block)) and the final position information. The data indicating the information on the head position of each data block (the data in the first, third and fifth stages from the top) is the SB No. from the top bit to the 8th bit (from the right in the figure), and the following 5 bits are Trp. No. and a 2-bit reserved area are provided. Furthermore, the last bit (the leftmost column in the figure) is an error flag, and 1 is recorded when the data is detected, and 0 is recorded otherwise. Further, the data indicating the information on the final position of the data block (the data in the first, third, and fifth stages from the top in the figure) has the last 1 bit as a reserved area.
[0059]
Based on such SYNC / ID detection request data, the SYNC / ID detection unit 22 starts reading from the position where the SB of SB No. A is detected, and reads data blocks composed of SBs that are continuous in track pair units. Detects three data blocks, and the Trp No. and SB No at the beginning and end of each data block are counted from the SB of SB No. A, for example, the Xth data block (the initial value of X is 0). In this case, the data is stored in the register FX at the head position and the register LX at the last position, and finally the SYNC / ID detection data is generated based on the registers FX and LX of the three data blocks to the latch data generation unit 62. Output.
[0060]
The PWM generator 63 performs pulse width modulation (PWM) on the output data (signal) for controlling the rotation of the capstan motor 34 input from the capstan servo calculator 71, and outputs it to the driver 32 as a PWM output. Output. For example, when reproducing at n-times speed, the frequency divider 64 generates a pulse waveform obtained by dividing the capstan motor rotation detection pulse input from the capstan motor rotation detection unit 33 by n, and outputs the pulse waveform to the time detection unit 65.
[0061]
The drum rotation detection unit 37 detects the rotation of the drum 36 and outputs a detection signal to the head switching pulse generation unit 38. The head switching pulse generator 38 generates a head switching pulse indicating the timing at which the rotating head is switched from the signal input from the drum rotation detector 37 and outputs the head switching pulse to the time detector 65.
[0062]
The time detection unit 65 detects the time data of the rising edges of the divided pulse input from the frequency divider 64 and the head switching pulse input from the head switching pulse generation unit 38, and the capstan Output to the servo calculation unit 71. The time detector 65 is actually composed of counter values that circulate at relatively long intervals. In the drawing, time data A indicates time data of the rising edge of the pulse obtained by dividing the capstan motor rotation detection pulse by the frequency divider 64, and time data B indicates time data of the rising edge of the head switching pulse. Is shown.
[0063]
The capstan servo calculation unit 71 is a program stored in advance in the ROM 202 and is supplied from the latch data generation unit 22 with the SB information for the above three blocks (the SB No. at the start position and the final position). A signal for controlling the rotation of the capstan motor 34 is generated from the latch data generated based on the SB No.) and the time data of the edges of various pulses input from the time detector 65.
[0064]
Next, with reference to FIG. 10 to FIG. 12, the principle of servo processing when the microcomputer 31 performs variable speed reproduction of the capstan motor 34 will be described. For example, when executing a 24 × speed reproduction process, as shown in FIG. 10, ideally, the rotary head 18 having a negative azimuth angle moves on the scan phase T in the upper right direction in the figure. Then, only the data recorded on the magnetic tape 35, that is, the SB on the track having the azimuth angle of-in each track pair is read.
[0065]
The SB No. is attached from the bottom in the figure, and the target SB to be read out is the SB of the Jth SB No. J from the bottom on the Trp No. 6 (center in the vertical direction in the figure). Position SB). In addition, the head switching pulse, the RF signal, and the reproduction data signal at this time are shown in FIGS. 11A, 11B, and 11C, respectively. The squares on the track shown in FIGS. 10 and 12 indicate data blocks. That is, the SB of J-th SB No. J from the bottom on Trp No. 6 is located at the center of the central cell of Trp No. 6 in FIG.
[0066]
Thus, in the case as shown in FIG. 10, as shown in FIG. 11B, the SB of the target SB No. Will be read out. However, actually, the scan phase T may be shifted in the left-right direction in the figure, which results in an error.
[0067]
Therefore, the microcomputer 31 reads based on the Trp No. of the three data blocks including the preceding and following data blocks including the SB of the target SB No. J and the SB No. located at the center thereof. The Trp No. unit deviation width and the SB No. unit deviation width of the output data are obtained, and the capstan motor 34 is controlled in accordance with either deviation width to thereby obtain the Trp No. unit (ie, data block unit). ) Or the position of the scan phase T is controlled in SB units.
[0068]
As shown in FIG. 10, the above-mentioned SB No. A is set as the SB of the head position read first on the data block corresponding to Trp No. 5. Accordingly, for example, as shown in FIG. 12, when the rotary head 18 scans along the scan phase T ′ shifted to the right in the drawing from the scan phase T shown in FIG. In this state, when data reading is delayed in time), the reading position is delayed as shown in FIGS. 11D and 11E. Therefore, the Ath (SB No. A) SB counted from the head switching pulse is Trp. Similarly, the target J-th SB No. J is the peak position of the data block of Trp No. 6 (the data block of the data block). This is read as the SB at a position later than the center position. As a result, the position of the read data block slides downward (in the direction in which the SB No. decreases) as shown by the arrow in FIG.
[0069]
Therefore, the microcomputer 31 controls the capstan motor 34 so as to decelerate the traveling speed of the magnetic tape 35 from the deviation width of the data block. More specifically, in the case of the microcomputer 31 shown in FIG. 12, although the SB of the target SB No. J is deviated from the center position of the target data block as shown in FIGS. 11D and 11E. When in the data block, the rotation of the capstan motor 34 is controlled in accordance with the deviation width in SB units. Further, for example, when the SB of the target SB No. J is detected outside the range of the target data block (data block on Trp No. 6), the microcomputer 31 is in units of data blocks. That is, control is performed in units of Trp Nos.
[0070]
FIG. 13 shows an example of a pattern of reading timing of RF signal and reproduction signal and control of SB No. unit or Trp No. unit according to the running speed of the magnetic tape 35. It is. FIG. 13A shows a head switching pulse, and shows that SB read out at timings t0 to t1 is reproduction data. 13B to 13N show timing charts showing respective timings from the left. The control method (Trp for Trp No. units, SB for SB No. units) is shown on the right side, and the right side thereof. Shows the Trp No. in which the SB currently being read exists. In the figure, the number given to the RF signal or the reproduction signal (SB detection signal) is the corresponding Trp No.
[0071]
For example, in FIG. 13B, since the traveling speed of the magnetic tape 35 is delayed, reading is fast, and the SB in the data block corresponding to Trp No. 4 is read as the SB of the target position. At this time, since the deviation of the reading position is equal to or larger than the Trp width (data block width), the control is in units of Trp No ..
[0072]
13C to 13F, the traveling speed of the magnetic tape 35 is delayed, but compared with FIG. 13B, the reading is delayed, and the SB in the block corresponding to Trp No. 5 is the SB of the target position. It has been read. Also at this time, since the deviation of the reading position is equal to or larger than the Trp width, the control is in units of Trp No ..
[0073]
In FIG. 13G, although the running speed of the magnetic tape 35 is delayed, the read delay is small compared to FIGS. 13B to 13F, and the SB in the block corresponding to the target Trp No. 6 is read. Yes. Accordingly, since the deviation of the reading position is within the Trp width, the control is in SB No. units.
[0074]
In FIG. 13H, the target position SB is read at the target timing.
[0075]
13I and 13J show a state in which the reading timing is delayed because the traveling speed of the magnetic tape 35 is too fast. However, since the SB in the block corresponding to the target Trp No. 6 has been read and the deviation of the read position is within the Trp width, the control is in SB No. units.
[0076]
13K to 13N show a state in which the traveling speed of the magnetic tape 35 is further increased, and its reading is delayed as compared with FIGS. 13I and J, and the SB in the block corresponding to Trp No. 7 is the target. Read as position SB. At this time, since the deviation of the reading position is equal to or larger than the Trp width, the control is in units of Trp No ..
[0077]
Next, the control configuration of the capstan servo calculation unit 71 will be described with reference to the control block diagram of FIG. In this specification, an example in which the capstan servo calculation unit 71 is configured by a program will be described. However, the configuration is not limited to this, and hardware having a similar function is used. It can also be configured.
[0078]
The capstan servo calculation unit 71 includes a speed error calculation unit 81, a phase error calculation unit 82, and a normal reproduction phase error calculation unit 84.
[0079]
The speed error calculation unit 81 detects the actual rotation cycle (speed) of the capstan motor 34, calculates a difference from the reference rotation cycle, and calculates this as a servo signal for the capstan motor 34. The speed error calculation unit 81 inputs the time data A input from the time detection unit 65 to the buffer 101 and the subtraction unit 102. The buffer 101 delays the input time data by a predetermined time (the time from the previous process to the current process) and outputs the delayed time data to the subtracting unit 102.
[0080]
The subtraction unit 102 calculates the difference between the time data A input from the time detection unit 65 and the time data A (the previous time data A) input from the buffer 101, thereby obtaining a current cap. The rotation period of the stun motor 34 is calculated and output to the subtraction unit 103.
[0081]
The subtracting unit 103 inputs the current rotation cycle of the capstan motor 34 inputted from the subtracting unit 102 and the rotation cycle of the reference capstan motor 34 stored in advance in the ROM 202 (a reference cycle (reference cycle in the figure)). A difference from a constant)) is obtained, and this is output as a speed error to the adder 85.
[0082]
Based on the latch data supplied from the latch data generating unit 62, the phase error calculation unit 82 is a data area for target variable speed reproduction (data area in which an image signal of an I picture to be read is recorded) during variable speed reproduction. : The above-mentioned block) and a phase error composed of a positional deviation between the actually detected data are calculated in Trp units or SB units. That is, as shown in FIG. 13, when the difference in position between the target SB and the detected SB is equal to or larger than the Trp width, the phase error calculation unit 82 detects a phase error in Trp units. That is, the switch 113 is connected to the terminal 113a, and the subtraction unit 111 obtains a difference between the Trp No. serving as the target position read from the ROM 202 and the Trp No. of the track including the SB detected based on the latch data. The phase error in Trp units is output to the gain adjustment unit 114 and the addition unit 116 via the switch 113. In FIG. 13, the target Trp No. is Trp No. 6, for example, in the case of FIG. 13B, the phase error in Trp units is 2 (= 6-4), and FIGS. In this case, 1 (= 6-5), 0 (= 6-6) in FIGS. 13G to J, and -1 (= 6-7) in FIGS. 13K to N.
[0083]
In addition, when the Trp to which the detected SB belongs and the target Trp are aligned by the above processing, that is, in the above example, in FIGS. 13G to J, the switch 113 is switched from the terminal 113a to the terminal 113b. The phase error in SB units is calculated. At this time, the subtraction unit 112 obtains a difference between the SB number of the target SB and the center SB number of the detected data block based on the latch data, and a phase that is a deviation in SB units from the difference. The error is calculated and output to the gain adjustment unit 114 and the addition unit 116 via the switch 113.
[0084]
The gain adjusting unit 114 adjusts the gain of the phase error signal input from the subtracting unit 111 or the subtracting unit 112 and outputs the adjusted signal to the integration calculating unit 115. The integral calculation unit 115 performs an integral calculation process on the input signal and outputs it to the addition unit 116. The addition unit 116 adds the signal input from the subtraction unit 111 or the subtraction unit 112 and the signal input from the integration calculation unit 115 and outputs the result to the gain adjustment unit 117. The gain adjustment unit 114, the integration calculation unit 115, and the addition unit 116 function as an LPF (Low Pass Filter), and smooth the phase error signal input from the subtraction unit 111 or the subtraction unit 112. . The gain adjusting unit 117 adjusts the gain of the signal input from the adding unit 116 and outputs the adjusted signal to the adding unit 85 via the switch 83.
[0085]
The normal reproduction phase error calculation unit 84 generates an error signal required during normal reproduction and outputs the error signal to the addition unit 85 via the switch 83. The switch 83 is connected to the terminal 83a at the time of variable speed reproduction, and outputs the phase error at the time of variable speed reproduction supplied from the phase error calculation unit 82 to the adder 85, and is connected to the terminal 83b at the time of normal reproduction, and is connected to the terminal 83b. The error signal for normal reproduction from the calculation unit 84 is output to the addition unit 85.
[0086]
The addition unit 85 is supplied from the phase error for variable speed reproduction input from the phase error calculation unit 82 or from the phase error and speed error calculation unit 81 for normal reproduction input from the phase error calculation unit 84 for normal reproduction. The speed error to be added is added and output to the gain adjustment unit 86.
[0087]
The gain adjustment unit 86 adjusts the gain of the speed error and phase error addition signals input from the addition unit 85, and outputs them to the integration calculation unit 87 and the addition unit 89. The integration calculation unit 87, the gain adjustment unit 88, and the addition unit 89 smooth the signal input from the gain adjustment unit 86 and output it to the PWM generation unit 63 as servo data.
[0088]
Next, servo processing during variable speed reproduction by the microcomputer 31 and the SYNC / ID detector 22 will be described with reference to the flowchart of FIG.
[0089]
In step S1, it is determined whether or not variable speed regeneration is commanded, and the process is repeated until variable speed regeneration is commanded. For example, when an operation button (not shown) is operated by the user to instruct variable speed reproduction, the process proceeds to step S2.
[0090]
In step S <b> 2, the latch data generation unit 62 transmits SYNC / ID detection request data to the SYNC / ID detection unit 22. In step S <b> 3, the SYNC / ID detection unit 22 executes SYNC / ID detection processing based on the SYNC / ID detection request data from the latch data generation unit 62.
[0091]
Here, the SYNC / ID detection processing by the SYNC / ID detection unit 22 will be described with reference to the flowchart of FIG.
[0092]
In step S21, the SYNC / ID detection unit 22 determines whether or not SYNC / ID detection request data has been transmitted, and repeats the processing until it is transmitted. For example, if it is determined that the SYNC / ID detection request data has been transmitted from the latch data generation unit 62 by the process in step S2 of FIG. 15, the process proceeds to step S22.
[0093]
In step S22, the SYNC / ID detection unit 22 receives the transmitted SYNC / ID detection request data, and initializes a counter j of the detected data block. That is, the counter j is initialized to j = 0, for example.
[0094]
In step S23, the SYNC / ID detector 22 determines whether the head switching pulse supplied from the latch data generator 62 is Hi, and repeats the processing until it is determined that it is Hi. For example, when the head switching pulse is switched to Hi as at the timing of time t11 shown in FIG. 17A, it is determined that it has become Hi, and the processing proceeds to step S24. Here, FIG. 17A shows the head switching pulse, FIG. 17B shows the RF signal, and FIG. 17C shows the SB detection signal.
[0095]
In step S24, the SYNC / ID detection unit 22 determines whether or not the SB is detected. For example, when SB11 is detected as illustrated in FIG. 17C, the SYNC / ID detection unit 22 determines that the SB has been detected. Proceed to step S25. In this case, as shown in FIG. 17A, the head switching pulse rises at time t11, and thereafter, SB11 is detected first after SB No. A as shown in FIG. 17C.
[0096]
In step S25, the SYNC / ID detection unit 22 determines whether data is recorded in the register Fj that stores the information of Block0FirstSB in FIG. In this case, since j = 0, it is determined whether or not data is recorded in the register F0. At this time, since there is no SB detected before SB11, no data is recorded in the register F0, so the processing proceeds to step S26.
[0097]
In step S26, the SYNC / ID detector 22 stores the SB No. and Trp No. data of the SB 11 in the register F0 based on the ID of the SB 11. In step S27, the SYNC / ID detector 22 determines whether or not the head switching pulse is in a Hi state. For example, in FIG. 17A, since the head switching pulse is Hi at the timing when SB11 is detected, the processing proceeds to step S24.
[0098]
In step S24, it is determined whether or not SB is detected. If SB is detected after SB11 as shown in FIG. 17B, the process proceeds to step S25. In step S25, it is determined whether or not data is recorded in the register Fj. In this case, since data of SB11 is recorded in F0, it is determined that there is data, and the process proceeds to step S28.
[0099]
In step S28, the SYNC / ID detection unit 22 obtains a difference between the SB number of the SB detected this time and the SB number of the SB detected last time, and determines whether or not the value is larger than the interpolation data M. When the number of interpolation SBs is 1, the interpolation data M is 2 (= number of interpolation SBs + 1), so it is determined whether or not the difference is greater than 2. For example, when SB is continuously detected as shown in FIG. 17C, the difference is 1, so it is determined that the difference is not greater than 2, and the process proceeds to step S29.
[0100]
In step S29, the SYNC / ID detector 22 records the SB No. and Trp No. data of the SB detected subsequent to the SB 11 based on the detected ID in the register Lj (register L0 in this case). The process proceeds to step S27. In step S27, it is determined whether or not the head switching pulse is in a Hi state. In this case, as shown in FIG. 17A, since the head switching pulse is in the Hi state, the process proceeds to Step S24.
[0101]
In step S24, it is determined whether or not SB is detected again. If SB is subsequently detected as shown in FIG. 17C, the process proceeds to step S25. In step S25, it is determined whether or not data is recorded in the register F0. At this time, since data is recorded in the register F0, it is determined that the data is recorded. Proceed to step S28.
[0102]
In step S28, the SYNC / ID detection unit 22 obtains a difference between the SB number of the SB detected this time and the SB number of the SB detected last time, and determines whether or not the value is larger than the interpolation data M. In this case, since SB is continuously detected, the difference is 1 and is smaller than the interpolation data M = 2. Therefore, the process proceeds to step S29. That is, when the head switching pulse is in the Hi state, unless the SB cannot be continuously detected beyond the number of interpolated SBs, in step S26, after the first SB data is stored in F0, step S24 is performed. Through the processing from S29 to S29, the data in the register L0 is sequentially overwritten on the data in the subsequent SB.
[0103]
In step S24, for example, as shown in FIG. 17C, when it is determined that the SB is not detected at the timing after SB12, the process proceeds to step S30. In step S30, the SYNC / ID detection unit 22 determines whether SB has not been detected continuously for M-1 times or more. That is, for example, as shown in FIG. 17C, since SB is not continuously detected at the timing after SB12, from M-1 (1 (= M-1 = 2-1) in this example) times. It is determined that the SB is not detected continuously. For example, since SB12 to SB13 in FIG. 17C are not continuously detected more than once, the process proceeds to step S31.
[0104]
In step S31, the SYNC / ID detection unit 22 determines that the difference between the SB No. recorded in the register Lj and the SB No. recorded in the register Fj is equal to or greater than the continuous data N (= the number of consecutive SBs−1), and It is determined whether or not the SB No. of the register L0 is equal to or greater than SB No. A serving as a boundary value. For example, in the example of FIG. 17C, it is determined that SB11 to SB12 are equal to or greater than a predetermined number of consecutive SBs. In addition, when it is determined that the SB No. of the register L0 is not less than the boundary value SB No. A, that is, when it is determined that a data block including a predetermined number or more of consecutive SBs is configured. The process proceeds to step S32.
[0105]
In step S32, the SYNC / ID detector 22 determines whether or not the counter j is equal to or greater than the initial value +2. In this case, since the counter j is an initial value, the process proceeds to step S33. In step S33, the SYNC / ID detection unit 22 increments the counter j by 1, and the process returns to step S27.
[0106]
That is, the data of the first block is acquired by the processing of step S33, the acquisition processing of the data stored in the registers F0 and L0 ends, and the value is determined (increment) As a result, data is stored in the registers F1 and L1 corresponding to the next block). In addition, the values of the registers F0 to F2 and L0 to L2 are obtained by repeating the processes of steps S24 to S34 described above.
[0107]
If it is determined in step S32 that the value of the counter j is equal to or greater than the initial value +2, in step S34, the SYNC / ID detection unit 22 in this case is the registers F0 to F2 and the registers L0 to L2, respectively. Is sent to the latch data generation unit 62 as SYNC / ID detection data, and the process ends. That is, in the example of FIG. 17C, the Trp No. belonging to the data blocks from SB11 to SB12 and the SB No. of SB11 are the Block0FirstSB data (data stored in the register F0) of the SYNC / ID detection data of FIG. The Trp No. belonging to the data blocks from SB11 to SB12 and the SB No. of SB12 are the Trp No. and SB13 belonging to the data blocks from SB13 to SB14 as the data of Block0LastSB (data stored in the register L0). SB No. is the Block1FirstSB data (data stored in the register F1). The Trp No. belonging to the data blocks from SB13 to SB14 and the SB No. of SB14 are the Block1LastSB data (stored in the register L1). As the data, the Trp No. belonging to the data blocks from SB15 to SB16 and the SB No. of SB15 are the Block2FirstSB data (the data stored in the register F2). Trp No. belonging to the data blocks from SB15 to SB16 and SB No. of SB16 are recorded as Block0LastSB data (data stored in the register F2), respectively.
[0108]
If it is determined in step S30 that the SB is not detected continuously for M-1 times or more, that is, if it is determined that the number of times that the SB cannot be detected is within the range of the interpolation data M, the processing is as follows. Returning to step S27, the subsequent processing is repeated. That is, as shown in FIGS. 18A to 18C, for example, when the number of SBs that could not be detected is one, such as the SBs 34 to S35 belonging to the central data block, the number of SBs that can be interpolated is obtained. Thru | or the process of S34 will be repeated. That is, in FIG. 18C, three data blocks SB31 to SB32, SB33 to SB36, and SB37 to SB38 are detected. Here, FIG. 18A shows a head switching pulse, FIG. 18B shows an RF signal, and FIG. 18C shows an SB detection signal.
[0109]
If it is determined in step S31 that the number is not equal to or greater than the predetermined number of consecutive SBs, or the SB No. in the register Lj is not greater than or equal to SB No. A serving as a boundary value, the process proceeds to step S35.
[0110]
In step S35, the SYNC / ID detector 22 resets the registers Fj and Lj, and the process returns to step S27. That is, for example, as shown in FIGS. 18D and 18E, when the SB cannot be detected more than the number of interpolated SBs (in this case, SB number 1 or more) as between the SBs 54 and SB55 belonging to the central block, or In step S28, when it is determined that the difference between the SB number of the SB detected this time and the SB number of the SB detected last time is larger than the interpolation value M, a data block is configured based on the continuous data N. In the state that cannot be regarded as the current state, the values of the registers Fj and Lj stored so far are reset. 18D and 18E, when SB55 is detected, the interval between SB54 and SB55 is equal to or greater than the number of interpolated SBs, and the number of consecutive SBs between SB53 to SB54 is not equal to or greater than N. Data is considered not to constitute a data block and is discarded.
[0111]
SB55 to SB56 are also reset in the same manner because the number of consecutive SBs is equal to or less than the prescribed number N of consecutive SBs. As a result, in the case of the SB detection signal as shown in FIGS. 18D and 18E, only two blocks SB51 to SB52 and SB57 to SB58 are detected. Also, the number of data blocks detected in this way may not necessarily be three. In this case, the SYNC / ID detection data of FIG. 9 is stored in a row. Here, FIG. 18D shows the RF signal, and FIG. 18E shows the SB detection signal.
[0112]
In the case of FIGS. 18F and 18G, in the central block, since there is one SB between SB73 and SB74, the interpolation is performed. However, between SB75 and SB76, the number of SBs is equal to the interval of two. Therefore, interpolation cannot be performed. As a result, in FIGS. 18F and 18G, SB73 to SB75 are regarded as central blocks. The SB 76 is discarded by the process of step S35. Here, FIG. 18F shows the RF signal, and FIG. 18G shows the SB detection signal.
[0113]
Further, if it is determined in step S31 that the SB No. of L0 is not greater than or equal to the boundary value SB No. A, the process proceeds to step S35 and the data in the registers Fj and Lj as described above. Is destroyed. That is, as shown in FIG. 19A, a data block composed of SBs near the boundary of SB No. A (SB at the beginning position of the data block in the figure is SB-F and SB at the final position is SB-L) is detected. In this case, this SB-L is not detected.
[0114]
Further, as shown in FIG. 19B, under the condition that the data block straddles the SB of SB No. A, the number of consecutive SBs of the SB-F that is the SB-F at the start position and the SB-L that is the final position is satisfied. If it is, it will be treated as a data block.
[0115]
Furthermore, as shown in FIG. 20, when the data block is configured to straddle both the SB of SB No. A and the head switching pulse, the detection of the SB starts from the state where the head switching pulse becomes Hi. Therefore, the SB-X existing at the head position of the data block in FIG. 20 is not detected, the first SB after the time t11 when the head switching pulse rises is detected as the SB-F of the head position, and the final position. Thus, the range from SB-F to SB-L is read as a data block.
[0116]
Furthermore, when the block is configured to straddle the time t12 when the head switching pulse falls as shown in FIG. 21, the detection of SB is only when the head switching pulse is in the Hi state, so The SB-F and the SB-L immediately before the time t12 are detected, and the SB-Y that is the SB at the actual final position of the data block is not detected.
[0117]
FIG. 22 schematically shows the processing of the flowchart described in FIG. 22A is the head switching pulse, FIG. 22B is the SB detection signal, FIG. 22C is the state of the register Lj, FIG. 22D is the state of the register Fj, FIG. 22E is the state of the registers F0 and L0, and FIG. FIG. 22G shows the states of the registers F1 and L1, and FIG. 22G shows the states of the registers F2 and L2, respectively. The numbers in FIGS. 22B to 22C are numbers for identifying SB.
[0118]
As shown in FIG. 22A, when the head switching pulse rises at time t11, the process starts (the process of step S23), the data of the first detected SB 201 is stored in the register F0, and the next detected SB 202 is stored in the register. The SB data stored in L0 (step S29) and then sequentially read is overwritten in the register L0 (steps S24 to S29).
[0119]
After the time t21 when the SB 250 is detected, since the SB is not continuously detected, when the condition for the continuous data N and that the SB No. of the register L0 is SB No. A or more are satisfied (step S31). As a result of the counter j being incremented (step S33), the registers F0 and L0 are determined as shown in FIG. 22E.
[0120]
Subsequently, when the SB 301 is detected at time t22, the data is stored in the register F1, and the next detected SB 302 is stored in the register L1 (step S29). The register L1 is overwritten (steps S24 to S29).
[0121]
After the time t23 when the SB 350 is detected, the SB is not continuously detected. Therefore, when it is satisfied that the number of consecutive SBs and the register L1 are equal to or greater than SB No. A (processing in step S31), the counter j Is incremented (step S33), the registers F1 and L1 are fixed as shown in FIG. 22F.
[0122]
Further, when the SB 401 is detected at time t24, the data is stored in the register F2, the next detected SB 402 is stored in the register L2 (the process of step S29), and then the SB data read sequentially is stored. The register L2 is overwritten (the processing in steps S24 to S29).
[0123]
Since the SB is not continuously detected after the time t25 when the SB 450 is detected, when the number of consecutive SBs and the register L2 are equal to or greater than SB No. A (processing in step S31), the counter j Is incremented (step S33), registers F2 and L2 are determined as shown in FIG. 22G. In the example of FIG. 22, a case where the number of consecutive SBs in one data block is 50 is described, but the number of SBs in one data block is not limited to this number.
[0124]
Now, the description returns to the flowchart of FIG.
[0125]
In step S4, the latch data generation unit 62 receives the SYNC / ID detection data transmitted from the SYNC / ID detection unit 22 by the process of step S3. In step S5, the latch data generation unit 62 executes a latch data generation process based on the SYNC / ID detection data.
[0126]
Here, the latch data generation processing of the latch data generation unit 62 will be described with reference to the flowchart of FIG. In the following description, Block0FirstSB data included in the SYNC / ID detection data is detected data F0, Block0LastSB data is detected data L0, Block1FirstSB data is detected data F1, Block1LastSB data is detected data L1, Block2FirstSB. This data is referred to as detection data F2, and the data of Block2 LastSB is referred to as detection data L2.
[0127]
In step S51, the latch data generation unit 62 determines whether or not the detection data F0 to F2 and the data of L0 to L2 are included based on the SYNC / ID detection data. That is, as described with reference to the flowchart of FIG. 15, the SYNC / ID detection data may not necessarily detect data corresponding to the three data blocks, so there is an undetected data block. It is determined whether or not to do so. More specifically, by confirming the error flag of the SYNC / ID detection data, when all the error flags are 1, it is confirmed that all of the SYNC / ID detection data is possible. If data exists for all blocks, that is, if it is determined that the detected data F0 to F2 and the data of L0 to L2 are included, the processing proceeds to step S52.
[0128]
In step S52, the latch data generation unit 62 treats the detection data F0 to F2 and L0 to L2 as they are as the processing data F0 to F2 and L0 to L2, and the processing data F0 to F2 and L0. Through L2 are cumulatively added and an average value is obtained and stored.
[0129]
In step S53, the latch data generation unit 62 refers to the processing data F0 to F2 and L0 to L2, and the SB numbers of the SBs of the SB numbers of the data block including the detected SB No. The average SB No. and the Trp No. to which the data block belongs are output to the capstan servo calculation unit 71 as latch data.
[0130]
If it is determined in step S51 that all the detection data F0 to F2 and L0 to L2 are not included, the processing proceeds to step S54.
[0131]
In step S54, the latch data generation unit 62 determines whether or not the SYNC / ID detection data includes the detection data F0, L0, F1, and L1. For example, when it is determined that the detection data F0, L0, F1, and L1 are included, the process proceeds to step S55.
[0132]
In step S55, the latch data generation unit 62 determines whether or not the detection data F0 and L0 of the SYNC / ID detection data is a value close to the average value of the processing data F0 and L0 stored therein. For example, if it is determined that the detection data F0 and L0 are not close to the average value of the processing data F0 and L0 stored in the self, the latch data generation unit 62 determines that the SYNC / ID detection data in step S56. Among these, the detection data F0, L0, F1, and L1 are used as the processing data F1, L1, F2, and L2, and the processing data F0 and F0 use the average value, and the processing proceeds to step S53.
[0133]
That is, when only two data blocks are included in the SYNC / ID detection data, the detection data F0 and L0 and the detection data F1 and L1 are not interchanged in time series. , L0 does not take a value close to the average value of the processing data F0, L0, as shown in FIGS. 24A to 24C, when the first data block is a block corresponding to Trp No. 5, 6, 7, It is considered that the data of the block corresponding to Trp No. 5) has not been detected. Therefore, in the case of FIGS. 24A to 24C, the processing data corresponding to SB 91 and 92 is the processing data F0 and L0, so these are generated using the average values stored by themselves, and thereafter The processing data F1, L1, F2, and L2 of the SBs 93, 94, 95, and 96 use the detection data F0, L0, F1, and L1 based on the SYNC / ID detection data. For comparison with the average value, for example, the absolute value of the difference between the average value of the detection data and the processing data is obtained. If the absolute value is equal to or less than the threshold value, the absolute value is close. It may be determined that it is not.
[0134]
24A is a head switching pulse, FIG. 24B is an RF signal, FIG. 24C is an SB detection signal, FIG. 24D is an RF signal, FIG. 24E is an SB detection signal, FIG. 24F is an RF signal, and FIG. Respectively indicate SB detection signals.
[0135]
If it is determined in step S55 that the detection data F0 and L0 of the SYNC / ID detection data are close to the average value of the processing data F0 and L0 stored in the SYNC / ID detection data, the latch data generation unit 62 is determined in step S57. Determines whether or not the detection data F1 and L1 of the SYNC / ID detection data are close to the average value of the processing data F1 and L1 stored therein. For example, when it is determined in step S57 that the detection data F1 and L1 of the SYNC / ID detection data are not close to the average value stored in the SYNC / ID detection data, the detection data F1 and L1 of the SYNC / ID detection data are 24D and E, it is assumed that the block corresponding to Trp No. 6 cannot be detected, and the block corresponding to Trp No. 7 is detected. In step S58, the latch data generation unit 62 The detection data F0, L0, F1, and L1 of the SYNC / ID detection data are used as the processing data F0, L0, F2, and L2, and the average value is used for the processing data F1 and L1, and the processing is performed in step S53. move on. That is, in the examples of FIGS. 24D and 24E, detection data F0 and L0 of SYNC / ID detection data corresponding to SB111 and SB112 are used as processing data F0 and L0, and processing data F1 and L1 are stored in SB113 and SB114. The average value of the corresponding processing data F1 and L1 is used, and the detection data F1 and L1 of the SYNC / ID detection data corresponding to SB115 and SB116 are used as the processing data F2 and L2.
[0136]
If it is determined in step S57 that the data F1 and L1 of the SYNC / ID detection data are close to the average value stored in the SYNC / ID detection data, the data corresponds to Trp No. 7 as shown in FIGS. In step S59, the latch data generation unit 62 regards the detection data F0, L0, F1, and L1 of the SYNC / ID detection data as processing data F0, L0, and F1. , L1, and the average value is used for the processing data F2, L2, and the process proceeds to step S53. That is, in the examples of FIGS. 24F and 24G, detection data F0 and L0 of SYNC / ID detection data corresponding to SB121 and SB122 are used as processing data F0 and L0, and processing data F1 and L1 are stored in SB123 and SB124. The detection data F1 and L1 of the corresponding SYNC / ID detection data are used, and the processing data F2 and L2 use the average value of the processing data F2 and L2 corresponding to the SB125 and SB126.
[0137]
If it is determined in step S54 that the SYNC / ID detection data does not include the processing data F0, L0, F1, and L1, the processing proceeds to step S60. In step S60, the latch data generation unit 62 determines whether or not the detection data F0 and L0 are included. For example, if it is determined that they are included, the process proceeds to step S61.
[0138]
In step S61, the latch data generation unit 62 determines whether or not the detection data F0 and L0 of the SYNC / ID detection data is close to the average value of the processing data F0 and L0. The process proceeds to step S62.
[0139]
In step S62, the latch data generation unit 62 regards the detection data F0 and L0 of the SYNC / ID detection data as data of the head data block, and uses the detection data F0 and L0 of the SYNC / ID detection data as the processing data. The average values are used as the processing data F1, L1, F2, and L2, and the processing proceeds to step S53.
[0140]
If it is determined in step S61 that the detection data F0 and L0 of the SYNC / ID detection data are not close to the average value of the processing data F0 and L0, the processing proceeds to step S63. In step S63, the latch data generation unit 62 determines whether or not the detection data F0 and L0 of the SYNC / ID detection data are close to the average value of the processing data F1 and L1, and are close to each other, for example. If it is determined, the process proceeds to step S64.
[0141]
In step S64, the latch data generation unit 62 regards the detection data F0 and L0 of the SYNC / ID detection data as data of the second data block, and processes the detection data F0 and L0 of the SYNC / ID detection data. The average value is used for the processing data F0, L0, F2, and L2, and the processing proceeds to step S53.
[0142]
If it is determined in step S63 that the detection data F0 and L0 of the SYNC / ID detection data are not close to the average value of the processing data F1 and L1, the latch data generation unit 62 detects the SYNC / ID in step S65. The data detection data F0, L0 are regarded as data of the third data block, and the detection data F0, L0 of the SYNC / ID detection data are used as the processing data F2, L2, and the processing data F0, L0, F1 are used. , L1 is used as the average value, and the process proceeds to step S53.
[0143]
If it is determined in step S60 that the data F0 and L0 are not included, in step S66, it is assumed that the SYNC / ID detection data does not include any data block data, and the processing data F0. Through F2 and L0 through L2 are all used from the average value, and the process proceeds to step S53.
[0144]
As described above, since the detection data F0 to F2 and L0 to L2 (SYNC / ID detection data) may not be detected as described above, the latch data generation unit 62 may detect the detection data F0 to F2. , And L0 to L2, processing data F0 to F2 and L0 to L2 corresponding to detection data of three data blocks are generated to generate latch data.
[0145]
Now, the description returns to the flowchart of FIG.
[0146]
In step S <b> 6, the capstan servo calculation unit 71 determines whether or not the detected SB is within the target Trp (in the data block) based on the latch data supplied from the latch data generation unit 62. . That is, for example, as described with reference to FIG. 13, in the case of 24 × speed reproduction processing, the detected SB (SB detected Jth from the leading edge of the head switching pulse) is the target Trp No. 6 It is determined whether it is within. Therefore, in step S6, it is determined whether or not the latch data is in the state of FIGS. 13G to 13J (whether it is FIGS. 13B to F and FIGS. 13K to N).
[0147]
If it is determined in step S6 that the detected SB is within the target Trp, that is, for example, in the case of a 24 × speed playback process, when it is determined that the state of FIGS. Proceed to step S7.
[0148]
In step S7, the capstan servo calculation unit 71 determines whether or not the switch 113 is connected to the terminal 113b. If it is determined that the switch 113 is connected, the process returns to step S1 and is connected to the terminal 113b. If it is determined that the switch 113 is not connected, the switch 113 is connected to the terminal 113a. Therefore, in step S8, the terminal 113a is switched to the terminal 113b.
[0149]
If it is determined in step S6 that the detected SB is not within the target Trp, that is, for example, in the case of a 24 × speed reproduction process, it is determined that the state is the state of FIGS. 13B to 13F and FIGS. If so, the process proceeds to step S9.
[0150]
In step S9, it is determined whether or not the switch 113 is connected to the terminal 113a. If it is determined that the switch 113 is connected, the process returns to step S1 and it is determined that the switch 113 is not connected to the terminal 113a. In this case, since the switch 113 is connected to the terminal 113b, in step S8, the terminal 113b is switched to the terminal 113a.
[0151]
With the above processing, the capstan servo calculation unit 71 determines at which timing the detected SB (the currently read SB) is read based on the latch data, and is within the Trp. In this case, the switch 113 is connected to the terminal 113b so that the phase error can be calculated in units of SB, and if not within the Trp, the switch 113 is connected to the terminal 113a so that the phase error can be calculated in units of Trp. .
[0152]
Next, with reference to the flowchart of FIG. 25, the error calculation process at the time of variable speed reproduction of the capstan servo calculation unit 71 will be described.
[0153]
In step S91, the capstan servo calculation unit 71 connects the switch 83 to the terminal 83a.
[0154]
In step S92, the speed error calculation unit 81 and the phase error calculation unit 82 calculate the speed error and the phase error, respectively, and the speed error calculation unit 81 sends the speed error to the addition unit 85 and the phase error calculation. The unit 82 outputs the phase error to the adding unit 85 via the switch 83 and adds them.
[0155]
Here, processing of the speed error calculation unit 81 and the phase error calculation unit 82 will be described.
[0156]
First, the speed error calculation process by the speed error calculation unit 81 will be described with reference to the flowchart of FIG. In step S <b> 111, the buffer 101 stores the time data A input from the time detection unit 65 and outputs the previously stored time data to the subtraction unit 102. For example, when the capstan motor rotation detection pulse input from the capstan motor rotation detector 33 is the pulse shown in FIG. 27A, the frequency divider 64 divides the frequency by, for example, 10 times as shown in FIG. 27B. Pulses are generated. The time of the rising edge detected by the time detector 65 is time data B. If it is now time t102, the time data of time t102 is input to the buffer 101 and the subtraction unit 102, and the buffer 101 subtracts the time data of time t101 stored before that time. 102 to be output.
[0157]
In step S112, the subtraction unit 102 takes the difference between the time data input from the buffer 101 and the time data input from the time detection unit 65, and outputs the difference to the subtraction unit 103 as the current rotation period of the capstan motor. That is, in this case, the time (t102−t101), which is the difference between the time t101 that is the time data input from the buffer 101 and the current time t102, is sent to the subtraction unit 103 as the current rotation period of the capstan motor. Is output.
[0158]
In step S113, the subtraction unit 103 takes the difference between the reference rotation cycle stored in advance in the ROM 202 and the current rotation cycle of the capstan motor (in this case (t102-t101)), and obtains this as a speed error. To the adder 85.
[0159]
The processing of the speed error calculation unit 81 is executed at the rising time of the capstan rotation detection pulse in FIG. 27B. Therefore, as shown in FIG. 27C, the processing of the rising edge of the divided pulse in FIG. It will be executed at the timing.
[0160]
Next, phase error calculation processing by the phase error calculation unit 82 will be described with reference to the flowchart of FIG.
[0161]
In step S131, it is determined whether or not the switch 113 is connected to the terminal 113a. If it is determined that the switch 113 is connected to the terminal 113a, that is, a phase error is calculated in Trp units. If so, the process proceeds to step S132.
[0162]
In step S132, the subtraction unit 111 of the capstan servo calculation unit 71 stores the Trp No. including the detected SB (for example, the SB No. J in FIG. 13) based on the latch data and the ROM 202. The difference from the target Trp No. is calculated and output to the gain adjustment unit 114 and the addition unit 116 via the switch 113 as a phase error signal.
[0163]
Here, the phase error in Trp units will be described with reference to FIG. FIG. 29 shows the structure of data for variable speed reproduction of 8 × speed reproduction. The data block A1 is a data block in which SB data for 8 × speed reproduction is recorded. When the rotary head 18 having an azimuth angle of − along the scan phase A scans in the direction of the arrow, − It passes through the target data block A1 on the track recorded with the azimuth angle. The data for 8 × speed reproduction is arranged at the same position in units of 8 Trp (block A2 in the figure is also arranged in the same manner), and variable speed reproduction is realized by reading these continuously. Yes.
[0164]
However, if the scan phase shifts depending on the running state of the magnetic tape 35, and the rotary head 18 scans along the scan phase B, for example, the data block A of Trp No. 5 on the data acquisition range that passes at the same timing. It will pass on '1. Accordingly, the phase error between the scan phase A and the scan phase B is represented by E1 in the figure, and E1 = Trp No. 6 (target Trp No.) − Trp No. 5 = 1 Trp. For example, when the magnetic head scans along the scan phase C, it passes over the data block A ″ 1 of Trp No. 7 in the data acquisition range that passes at the same timing. Accordingly, the phase error between the scan phase A and the scan phase C is represented by E0 in the figure, and E0 = Trp No. 6 (target Trp No.) − Trp No. 7 = −1 Trp. That is, the phase error in Trp units is output.
[0165]
In step S <b> 133, the gain adjustment unit 114, the integration calculation unit 115, and the addition unit 116 smooth the phase error signal input from the subtraction unit 111 and output the signal to the gain adjustment unit 117.
[0166]
In step S <b> 134, the gain adjusting unit 117 adjusts the gain of the input phase error signal and outputs the adjusted signal to the adding unit 85 via the switch 83.
[0167]
If it is determined in step S131 that the switch 113 is not connected to the terminal 113a, that is, if the switch 113 is connected to the terminal 113b and is in a state of calculating a phase error in SB units, the processing is as follows. The process proceeds to step S135.
[0168]
In step S135, the subtraction unit 112 of the capstan servo calculation unit 71 stores the SB No. of the detected SB (for example, SB No. J in FIG. 13) and the ROM 202 based on the latch data. The difference in SB units from the target SB No. is calculated and output to the gain adjustment unit 114 and the addition unit 116 via the switch 113 as a phase error signal.
[0169]
That is, as described in the flowchart of FIG. 15, the detection of the phase error in units of SB No. is when the data block including the detected SB is detected in the target Trp. This represents the phase error in SB units within the target Trp.
[0170]
FIG. 30 shows the relationship between the phase error in Trp units and the phase error in SB units for each scan phase. FIG. 30A shows blocks A1 to A3 (tracks scanned by a magnetic head having an azimuth angle) including a scan phase and an SB for 8 × speed variable speed reproduction, and a thick line is scanned by a rotating head 18 having an azimuth angle. Shows the scan phase. Further, the thin line indicates the scan phase when the rotary head 18 having a + azimuth angle scans. FIG. 30B shows the transition of the phase error in Trp units for each scan phase when the horizontal axis is the Trp No. intersecting with the center line of the scan phase of the rotary head 18 having the azimuth angle indicated by the bold line. Here, the vertical axis indicates the number of Trp indicating a phase error. As shown in FIG. 30B, the scan phase changes periodically. In the range of Trp No. 6 to 2, the traveling speed of the magnetic tape 35 is high, and in the range of Trp No. 2 to 6, the magnetic phase is magnetic. The case where the running speed of the tape 35 is slow is shown.
[0171]
FIG. 30C shows a phase error in SB units. In this example, the track is shifted by 1 Trp centering on the track having the target azimuth angle of Trp No. 6, and the upper limit value (Max) and lower limit value (Min) are fixed values. In other words, it is only necessary to be able to show the transition within the target Trp, so it is sufficient that the upper limit value and the lower limit value are set to be equal to each other in absolute value. The capstan servo process is executed so that the phase error becomes zero.
[0172]
FIG. 31 shows the timing of the above processing. FIG. 31A shows a head switching pulse, TD1 to TD3 indicate detected blocks, and SD1 to SD3 indicate target data blocks. FIG. 31B shows the processing timing. FIG. 31C shows the timing of the rising pulse of time data A (frequency-divided pulse).
[0173]
That is, as shown in FIG. 31A, when the head switching pulse rises at the timings t11, t13, and t15, the SYNC / ID detection unit 22 performs the block TD1, at the timings t121, t123, and t125 that are the centers of the pulses. The data of TD2 and TD3 are read out and transferred to the latch data generation unit 62 as SYNC / ID detection data at times t12, t14, and 16.
[0174]
Based on the SYNC / ID detection data, the latch data generation unit 62 performs the timing at times t131, 133, and 135 as shown in FIG. 31B, that is, the time when the pulse of the time data A rises as shown in FIG. 31C. Latch data is generated at timings t155, t162, and t169, and transferred to the capstan servo calculation unit 71. Based on the latch data, the capstan servo calculation unit 71 sets the target SB No. (corresponding times t122, t124, 126) stored in advance and the detected SB No. (corresponding times t121, From the comparison with t123, 125), the phase error is calculated at timings t132, t134, t136, and the rotation of the capstan motor 34 is controlled. By this process, the result of the capstan servo calculation process based on the latch data is reflected at the timings t156, t163, and t170, which is the timing immediately after the rotation of the capstan motor 34 is controlled.
[0175]
Now, the description returns to the flowchart of FIG.
[0176]
In step S <b> 93, the addition unit 85 adds the speed error from the speed error calculation unit 81 to the phase error from the phase error calculation unit 82 and outputs the result to the gain adjustment unit 86. In step S <b> 94, the gain adjustment unit 86 adjusts the gain of the input signal and outputs the signal to the integration calculation unit 87 and the addition unit 89. In step S95, the integral calculation unit 87, the gain adjustment unit 88, and the addition unit 89 constitute an LPF, smooth the signal input from the gain adjustment unit 86, and output the smoothed signal to the PWM generation unit 63, and again in step S92. Returning to the process, the subsequent processes are repeated.
[0177]
With the above processing, simply detecting data of three data blocks near the target SB, a phase error in Trp units is obtained, and capstan servo processing in Trp units is executed by that processing, When a block on the target Trp can be read, a phase error in SB units is continuously obtained, and target data can be acquired in SB units by corresponding capstan servo processing.
[0178]
In the above example, the case where the detection position of the target data block is the central portion of the magnetic tape has been described. However, as shown in FIG. 32, the data blocks B1 to B3 are separated from the data blocks A1 to A3. As described above, target data blocks may be set at different positions even on the same scan phase. By setting in this way, even when a linear shift that may occur due to a mechanical problem occurs on the data blocks A1 to A3, for example, the target position is switched to the data blocks B1 to B3. Can be suppressed. Also, data blocks C1 to C3 for reverse speed shift reproduction may be recorded.
[0179]
As shown in FIG. 33, target data blocks A1 to A3 are data blocks A1-1 to A1-3, data blocks A2-1 to A2-3, and data blocks A3-1 to A3-3. As shown, by recording the same data block a plurality of times (for example, three times) on one track, the range that can be read by the rotary head 18 can be set wide, resulting in the occurrence of errors. Can be suppressed. Also at this time, the target position may be set on another track that can be detected on the same scan phase as shown in FIG. 32. In this case, the number of data block recordings is changed as shown in FIG. (Blocks B1 to B3 in FIG. 33 are twice). Further, the data for reverse speed shift reproduction may be recorded a plurality of times as in data blocks C1-1 and C1-2. As a matter of course, the number of times the same block is recorded on the same track is not limited to the above-described one to three times, and may be any other number.
[0180]
Furthermore, although an example in which data of three data blocks is read as SYNC / ID detection data for detecting a phase error has been described, other numbers of data blocks may be used.
[0181]
Further, in the above description, the case where the capstan servo calculation process is executed by Trp No. has been described. However, as a matter of course, the capstan servo calculation process may be executed by Tr No.
[0182]
According to the above, since the servo processing by the phase error in the Trp unit is executed and then the servo processing in the SB unit is executed, the image signal recorded on the tape-like recording medium can be reproduced even during the variable speed reproduction. It is possible to reproduce stably and further reduce the processing time until the reproduction state is stabilized. Also, in the SB read processing, it is not necessary to read all SBs by reading only the SBs on the Trp near the Trp including the SB to be read, so the configuration necessary for the SB read processing is simplified. In addition, the cost can be reduced and the processing speed can be improved.
[0183]
The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processes is executed by software, a program constituting the software may execute various functions by installing a computer incorporated in dedicated hardware or various programs. For example, it is installed from a recording medium in a general-purpose personal computer or the like.
[0184]
As shown in FIG. 7, this recording medium is not limited to the HDD 204 in which the program is recorded, but is distributed to provide the program to the user separately from the computer. Including a flexible disk), optical disk 212 (including compact disk-read only memory (CD-ROM), DVD (digital versatile disk)), magneto-optical disk 213 (including MD (mini-disk)), or semiconductor memory 214 Consists of package media (including Memory Stick).
[0185]
In this specification, the step of describing the program recorded on the recording medium is not limited to the processing performed in time series in the order described, but of course, it is not necessarily performed in time series. Or the process performed separately is included.
[0186]
【The invention's effect】
  According to the image reproducing apparatus and method and the program of the present invention, the position of the track on the tape-shaped recording medium in which the information for variable speed reproduction exists among the image information is stored as the target position.In addition, among the image information, the position of the sync block on the tape-shaped recording medium where the image information for variable speed reproduction exists is further stored as the target position.The information on the track in the vicinity where the image information for variable speed playback recorded on the tape-like recording medium existsAs data block unit information consisting of a plurality of sync blocks continuous for a predetermined number or moreRead and detect the track position of the read informationIn addition, the sync block position of the read information is further detected.AndTruckTarget position and detectedTruckCompare with positionAnd compare the stored sync block target position with the detected sync block position.AndPer trackBased on the comparison result, the feeding speed of the tape-shaped recording medium is controlled in units of tracks.At the same time, with the control in units of tracks completed, based on the comparison results of the sync blocks, further control the feed speed of the tape-shaped recording medium in units of sync blocks,,Interpolate non-consecutive sync blocks when the number of non-continuous sync blocks is less than or equal to the predetermined number of sync blocks constituting the data blockAs a result, stable reproduction can be performed during variable speed reproduction, and further, the processing time until the reproduction state is stabilized can be shortened.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating MPEG compression.
FIG. 2 is a diagram illustrating a drum.
FIG. 3 is a diagram illustrating an operation in which a rotary head reads an image signal recorded on a magnetic tape.
4 is a diagram for explaining an RF signal detected by the rotary head of FIG. 3; FIG.
FIG. 5 is a diagram showing a configuration of an embodiment of a recording system of a digital video tape recorder to which the present invention is applied.
FIG. 6 is a diagram showing a configuration of a playback system of a digital video tape recorder to which the present invention is applied.
7 is a block diagram of the vicinity of the microcomputer in FIG. 3;
FIG. 8 is a diagram showing a configuration of SYNC / ID detection request data.
FIG. 9 is a diagram showing a configuration of SYNC / ID detection data.
FIG. 10 is a diagram for explaining scanning of data on a magnetic tape by a rotary head.
FIG. 11 is a diagram showing a detection signal when data on a magnetic tape is scanned by a rotary head as shown in FIG.
FIG. 12 is a diagram for explaining scanning of data on a magnetic tape by a rotary head.
FIG. 13 is a diagram for explaining a phase error pattern when data on a magnetic tape is scanned by a rotary head.
14 is a control block diagram of a capstan servo calculation unit in FIG. 4; FIG.
FIG. 15 is a flowchart illustrating servo processing during variable speed reproduction.
FIG. 16 is a flowchart illustrating SYNC / ID detection processing.
FIG. 17 is a diagram for explaining SYNC / ID detection processing;
FIG. 18 is a diagram for explaining SYNC / ID detection processing;
FIG. 19 is a diagram for explaining SYNC / ID detection processing;
FIG. 20 is a diagram for explaining SYNC / ID detection processing;
FIG. 21 is a diagram for explaining SYNC / ID detection processing;
FIG. 22 is a diagram schematically illustrating SYNC / ID detection processing.
FIG. 23 is a flowchart illustrating latch data generation processing.
FIG. 24 is a diagram for explaining latch data generation processing;
FIG. 25 is a flowchart for explaining error calculation processing during variable speed reproduction;
FIG. 26 is a flowchart illustrating a speed error calculation process.
FIG. 27 is a timing chart illustrating speed error calculation processing.
FIG. 28 is a flowchart illustrating phase error calculation processing.
FIG. 29 is a diagram illustrating a phase error calculation process.
FIG. 30 is a diagram illustrating a phase error calculation process.
FIG. 31 is a timing chart illustrating phase error calculation processing.
FIG. 32 is a diagram for describing phase error calculation processing;
FIG. 33 is a diagram for explaining phase error calculation processing;
[Explanation of symbols]
31 microcomputer, 32 driver, 33 capstan motor rotation detector, 34 capstan motor, 35 magnetic tape, 36 drums, 37 drum rotation detector, 38 head switching pulse generator, 51 RF envelope detector, 52 comparator, 61 CPU, 62 Latch data generator, 63 PWM generator, 64 divider, 65 Time detector, 71 Capstan servo calculator, 81 Speed error calculator, 82 Phase error calculator

Claims (12)

In an image reproducing apparatus that reproduces image information recorded on a tape-shaped recording medium at a variable speed,
Among the image information, the position of the track on the tape-shaped recording medium where the image information for variable speed reproduction exists is stored as a target position, and the image information for variable speed reproduction exists among the image information. Target position storage means for further storing the position of the sync block on the tape-shaped recording medium as the target position;
Reading means for reading information on a track in the vicinity where the image information for variable speed reproduction recorded on the tape-shaped recording medium exists as information in units of data blocks including a plurality of sync blocks that are continuous by a predetermined number or more ;
Position detecting means for detecting the position of the track of the information read by the reading means, and further detecting the position of the sync block of the information read by the reading means ;
And the target position of the tracks stored by said target position storage means, together with comparing the position of the track detected by said position detecting means, the sync block stored by said target position storage means Comparing means for comparing the target position of the position and the position of the sync block detected by the position detecting means ;
Based on the comparison result of each track unit by the comparison unit, the feeding speed of the tape-shaped recording medium is controlled by the track unit, and the control of the track unit is completed, based on the comparison result of the sync block. A feed speed control means for further controlling the feed speed of the tape-shaped recording medium in units of sync blocks ;
An image reproducing device comprising: sync block interpolation means for interpolating the non-continuous sync blocks when the number of non-continuous sync blocks is less than or equal to a predetermined number of sync blocks constituting the data block . The reading means reads information on a track in the vicinity where one piece of image information for variable speed reproduction exists among a plurality of pieces of image information for variable speed reproduction recorded on the tape-shaped recording medium. The image reproducing apparatus according to claim 1. When the control is performed in sync block units, the reading means is different from the one piece of the image information for variable reproduction recorded on the tape-shaped recording medium, and is one other variable reproduction. The image reproducing apparatus according to claim 2 , wherein the information on a track in the vicinity where image information for use exists is read. In an image reproducing method of an image reproducing apparatus for performing variable speed reproduction of image information recorded on a tape-shaped recording medium,
Wherein among the image information, the position of the track on said tape-shaped recording medium in which information for variable speed reproduction is present stores as a target position, of the image information, the tape image information for the variable speed reproduction is present A target position storing step of further storing the position of the sync block on the recording medium as the target position;
A reading step of reading information on a track in the vicinity where the image information for variable speed reproduction recorded on the tape-shaped recording medium exists as information in units of data blocks including a plurality of sync blocks that are continuous a predetermined number or more ;
A position detecting step of detecting a position of the track of the information read in the process of the reading step, and further detecting a position of the sync block of the information read by the process of the reading step ;
The target position of the track stored in the process of the target position storing step is compared with the position of the track detected in the process of the position detecting step, and stored by the process of the target position storing step. A comparison step of comparing the target position of the sync block being performed and the position of the sync block detected by the processing of the position detection step ;
Based on the comparison result in units of tracks in the processing of the comparison step, the feed speed of the tape-shaped recording medium is controlled in units of tracks, and in the state where the control in units of tracks has been completed, A feed speed control step for further controlling the feed speed of the tape-shaped recording medium in units of sync blocks ;
And a sync block interpolation step for interpolating the non-continuous sync blocks when the number of non-continuous sync blocks is less than or equal to a predetermined number of sync blocks constituting the data block. . In the reading step, information on a track in the vicinity where one piece of the image information for variable speed reproduction of the plurality of pieces of image information for variable speed reproduction recorded on the tape-shaped recording medium exists is obtained. Read
  The image reproduction method according to claim 4, wherein: The process of the reading step is different from the one piece of image information for variable speed reproduction recorded on the tape-shaped recording medium when the control in units of the sync block is performed, Read the information on a nearby track where image information for variable speed playback exists
  The image reproducing method according to claim 5, wherein: A program for controlling an image reproducing device that performs variable speed reproduction of image information recorded on a tape-shaped recording medium,
Controls storage as a target position of a track position on the tape-shaped recording medium in which information for variable speed reproduction exists among the image information, and includes image information for variable speed reproduction in the image information. A target position storage control step of further controlling storage of the position of the sync block on the tape-shaped recording medium as the target position;
Controls reading of information as a unit of a data block composed of a plurality of sync blocks continuous over a predetermined number of pieces of information on a track in the vicinity where the image information for variable speed reproduction recorded on the tape-shaped recording medium exists A read control step;
Position detection control for controlling the detection of the position of the track of the information read in the process of the read control step and further controlling the detection of the position of the sync block of the information read by the process of the read control step Steps,
Wherein said target position of the track stored in the process of the target position memory control step is controlled, to control the comparison of the position of the track which is detected is controlled by the processing of the position detection control step, the A comparison control step for controlling a comparison between the target position of the sync block stored by the process of the target position storage control step and the position of the sync block detected by the process of the position detection control step ;
Based on the comparison result of the track unit in the process of the comparison control step, the feed speed of the tape-shaped recording medium is controlled by the track unit, and the comparison result of the sync block in the state where the control by the track unit is completed A feed speed control step for controlling the feed speed of the tape-shaped recording medium in sync block units ,
A sync block interpolation control step for controlling interpolation of the discontinuous sync blocks when the number of discontinuous sync blocks is less than or equal to a predetermined number among the sync blocks constituting the data block. A recording medium on which a computer-readable program is recorded. The processing of the reading control step is information on a track in the vicinity of one of the plurality of image information for variable reproduction recorded on the tape-shaped recording medium. Control loading of files
  The recording medium according to claim 7. The processing of the reading control step is the one for the variable speed reproduction recorded on the tape-shaped recording medium when the control is performed in units of the sync block. Control reading of the information on a track in the vicinity where there is another one of the image information for variable speed reproduction different from the image information of
  The recording medium according to claim 8. To a computer that controls an image reproducing device that performs variable speed reproduction of image information recorded on a tape-like recording medium,
Controls storage as a target position of a track position on the tape-shaped recording medium in which information for variable speed reproduction exists among the image information, and includes image information for variable speed reproduction in the image information. A target position storage control step of further controlling storage of the position of the sync block on the tape-shaped recording medium as the target position;
Controls reading of information as a unit of a data block composed of a plurality of sync blocks continuous over a predetermined number of pieces of information on a track in the vicinity where the image information for variable speed reproduction recorded on the tape-shaped recording medium exists A read control step;
Position detection control for controlling the detection of the position of the track of the information read in the process of the read control step and further controlling the detection of the position of the sync block of the information read by the process of the read control step Steps,
Wherein said target position of the track stored in the process of the target position memory control step is controlled, to control the comparison of the position of the track which is detected is controlled by the processing of the position detection control step, the A comparison control step for controlling a comparison between the target position of the sync block stored by the process of the target position storage control step and the position of the sync block detected by the process of the position detection control step ;
Based on the comparison result of the track unit in the process of the comparison control step, the feed speed of the tape-shaped recording medium is controlled by the track unit, and the comparison result of the sync block in the state where the control by the track unit is completed A feed speed control step for controlling the feed speed of the tape-shaped recording medium in sync block units ,
A program for executing a sync block interpolation control step for controlling the interpolation of the non-continuous sync blocks when the number of non-continuous sync blocks is less than or equal to a predetermined number among the sync blocks constituting the data block . The processing of the reading control step is information on a track in the vicinity of one of the plurality of image information for variable reproduction recorded on the tape-shaped recording medium. Control loading of files
  The program according to claim 10. The process of the reading control step is different from the one piece of image information for variable speed reproduction recorded on the tape-shaped recording medium when the control in units of the sync block is performed. Control reading of the information on a track in the vicinity where the image information for variable speed reproduction exists
  The program according to claim 11.

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