JP2001352509A - Image reproducing device and its method, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image reproducing device that can stably reproduce an image signal recorded on a recording tape medium even at a variable speed reproduction. SOLUTION: A capstan servo-arithmetic section 71 obtains a speed error from time data C received from a time detection section 65 based on a capstan motor rotation detection pulse. Furthermore, the capstan servo arithmetic section 71 obtains an SB phase error based on an SB No. and Tr No. and an SB phase error detected by a SYNC/ID detection section 22. Furthermore, the capstan servo-arithmetic section 71 obtains a time phase error from time data B outputted from a time detection section 62 based on time data A received from the time detection section 62 depending on the RF position detection pulse outputted from an RF signal position detection section 30 and time data B outputted from the time detection section 62. The capstan servo-arithmetic section 71 outputs a signal to control the capstan motor to a PWM generating section 63 depending on the error above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reproducing apparatus and method, and a recording medium, and more particularly to an image reproducing apparatus which can stably reproduce an image signal recorded on a tape-shaped recording medium even during variable-speed reproduction. The present invention relates to a reproducing apparatus and a method, and a recording medium.

[0002]

2. Description of the Related Art In a digital video tape recorder, an image signal is, for example, MPEG (Moving Picture).
Experts Group) and recorded on magnetic tape. FIG. 1 shows an example in which 15 frames in a stream data of an image signal are set as a GOP (Group of Picture) and the image signal is compressed by the MPEG method. FIG.
A indicates the original image signal in which the image signals are arranged in chronological order, and Nos. 0 to 14 indicate the numbers of the respective frames of the image signal.

FIG. 1B shows that an image signal A of FIG. 1A is composed of an I picture (Intra Coded Picture) and a P picture (Predict Picture).
ive Coded Picture) and B picture (Bidirecti
Only Coded Picture) shows an image signal compressed by the MPEG method in three types of pictures. The number at the lower right of each of I, P, and B in the image signal B indicates the frame number of the original image signal A.

[0004] An I picture is an image signal compressed by only an image signal in a frame. That is, for example, the I picture I ₂ of the image signal B is the frame No. ₂ of the image signal A.
Is an image signal obtained by compressing only the image signal.

[0005] A P picture is an image signal compressed by using an image signal of a temporally past I picture or P picture in addition to an image signal in a frame. That is, for example, the P picture P ₅ of the image signal B is
and an image signal of O.5, a compressed image signal by using the previous image signal of the I-picture I _2.

[0006] A B picture is an image signal that is compressed using the image signals of a temporally preceding and succeeding I picture and a P picture in addition to the image signal in the frame. That is, for example, the B picture B ₀ of the image signal B is the frame N
0, an image signal of an I picture I ₂ that is earlier in time, and an image signal of a P picture P ₅ that is later in time.

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 decompression processing of the P picture and the B picture requires one or both of the preceding and succeeding I and P pictures, or both, and therefore cannot be performed independently. .

When an image signal compressed by the MPEG system is reproduced at a variable speed on a magnetic tape, the magnetic head reads the image signal alternately over a plurality of tracks having different azimuth angles. The signal is an intermittent signal. Therefore, if an image signal such as a P picture or a B picture that cannot be independently expanded is intermittently read from the magnetic head, the image cannot be reproduced because there is no image to be referenced.

Therefore, the image signal of an I picture is arranged at a predetermined position on a magnetic tape as an image signal for variable speed reproduction, and the magnetic head is controlled so as to continuously read out only the I picture, thereby changing the speed. Playback is being done. At this time, the video tape recorder detects the rotation cycle of the capstan motor for moving the magnetic tape, finds a difference (speed error) between the detected rotation cycle and a reference cycle stored in advance, and obtains the speed error. Controls the rotation speed of the capstan motor so that the magnetic head detects only the image signal of the I picture on the magnetic tape.

[0010]

However, in the above-described configuration, the speed of the capstan motor can be controlled during variable speed reproduction. If a slip occurs between the magnetic tapes or if the magnetic tape expands or contracts, it is not possible 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 is recorded on the magnetic tape cannot be accurately matched, and a part of the reproduced image is missing or the update rate of the image is deteriorated. There was a problem that

The present invention has been made in view of such a situation, and aims to stably reproduce an image signal recorded on a tape-shaped recording medium even during variable-speed reproduction.

[0012]

According to the present invention, there is provided an image reproducing apparatus, comprising: information recorded on a tape-shaped recording medium;
Target position storage means for storing the position of the information for variable speed reproduction on the tape-shaped recording medium as a target position; reading means for reading information recorded on the tape-shaped recording medium; and information read by the reading means. Reading position detecting means for detecting a position on the tape-shaped recording medium as a reading position, and difference detection for detecting a difference between the target position stored by the target position storing means and the reading position detected by the reading position detecting means. Means, and feed speed control means for controlling the feed speed of the tape-shaped recording medium based on the difference between the target position and the read position detected by the difference detection means.

The target position storage means stores a target position,
It is stored as a track number and a sync block number of the tape-shaped recording medium, and the reading position detecting means includes:
The reading position is detected as a track number and a sync block number of the tape-shaped recording medium, and the difference detecting means calculates a difference between the target position and the reading position from a difference between the track number and the sync block number of the target position and the reading position. It can be detected.

Target position detection means for detecting the target position stored by the target position storage means from the tape-shaped recording medium; and target position detection time detection for detecting the time at which the target position is detected by the target position detection means. Means, and a reading position detection time detecting means for detecting a time at which the reading position is detected by the reading position detecting means, wherein the difference detecting means is detected by the target position detecting time detecting means. The difference between the target position and the reading position is detected from the difference between the time and the time detected by the reading position detection time detecting means.

The reading position detecting time detecting means includes:
The reading position is detected by the reading position detecting means using one or both of the rising edge and the falling edge of the pulse signal obtained by binarizing the envelope signal of the reproduction RF signal using a predetermined threshold value. The detected time can be detected.

The feed speed control means includes: a difference between the target position and the read position detected from the difference between the track number and the sync block number of the target position and the read position detected by the difference detection means; Based on one or both of the difference between the target position and the reading position detected from the difference between the time detected by the target position detection time detecting means and the time detected by the reading position detection time detecting means, a tape-shaped The feeding speed of the recording medium can be controlled.

A head switching pulse reference target position detection time detecting means for detecting a time at which a target position is detected based on a rising edge or a falling edge of the head switching pulse signal, and an envelope signal of the reproduction RF signal is determined. And a reading position detection time detecting means for detecting a time at which the reading position is detected by the reading position detecting means based on the binarized pulse signal using the threshold value. The means is configured to detect a difference between the target position and the reading position from a difference between the time detected by the head switching pulse reference target position detection time detecting means and the time detected by the reading position detection time detecting means. be able to.

The reading position detection time detecting means includes:
The read position is detected by the read position detecting means using one or both of the rising edge and the falling edge of the pulse signal obtained by binarizing the envelope signal of the reproduction RF signal using a predetermined threshold. The detected time can be detected.

The feed speed control means includes a difference between the target position and the read position detected from the difference between the track number and the sync block number of the target position and the read position, which are detected by the difference detection means;
Based on one or both of the difference between the target position and the reading position detected from the difference between the time detected by the head switching pulse reference time detecting means and the time detected by the reading position detection time detecting means, the tape The feed speed of the shape recording medium can be controlled.

The image reproducing method according to the present invention includes a target position storing step of storing, as a target position, a position on the tape-shaped recording medium of information for variable-speed reproduction among information recorded on the tape-shaped recording medium. A reading step for reading information recorded on the tape-shaped recording medium, a reading position detecting step for detecting a position on the tape-shaped recording medium of the information read in the processing of the reading step as a reading position, and a target position storage. A difference detection step for detecting a difference between the target position stored in the processing of the step and the reading position detected in the processing of the reading position detection step, and a target position and a reading position detected in the processing of the difference detection step. And a feed speed control step of controlling the feed speed of the tape-shaped recording medium based on the difference between the two.

[0021] The program of the recording medium of the present invention is a program for controlling the storage of the position on the tape-shaped recording medium of the information for variable-speed reproduction among the information recorded on the tape-shaped recording medium. A position storage control step, a read control step for controlling reading of information recorded on the tape-shaped recording medium, and a read position of a position on the tape-shaped recording medium of the information read in the processing of the read control step. A reading position detection control step for controlling detection, and a difference detection control for controlling detection of a difference between the target position stored in the processing of the target position storage control step and the reading position detected in the processing of the reading position detection control step. Step and a tape-shaped record based on the difference between the target position and the read position detected in the process of the difference detection control step. Characterized in that it comprises a feed speed control step for controlling the feed rate of the medium.

In the image reproducing apparatus and method of the present invention, and the program of the recording medium, of the information recorded on the tape-shaped recording medium, the position of the information for variable-speed reproduction on the tape-shaped recording medium is the target. Information stored as a position and recorded on a tape-shaped recording medium is read,
The position of the read information on the tape-shaped recording medium is detected as the read position, and the difference between the stored target position and the detected read position is detected and detected.
The feed speed of the tape-shaped recording medium is controlled based on the difference between the target position and the reading position.

[0023]

2 and 3 are diagrams showing the configuration of an embodiment of a digital video tape recorder according to the present invention. FIG. 2 mainly shows a configuration of a recording system of an image signal, and FIG. 3 mainly shows a configuration of a reproduction system.

First, the configuration of the recording system shown in FIG. 2 will be described.

An A / D (Analog / Digital) converter 1 converts an input image signal from an analog signal to a digital signal and outputs it to a compression processing unit 2. The compression processing unit 2 performs DCT (Discrete Cosine Transformation) conversion on the image signal converted into a digital signal input from the A / D converter 1, and then compresses the image signal using the MPEG method as described above to generate data for variable speed reproduction. The data is output to the section 3 and the data multiplexing section 4.

The variable-speed reproduction data generator 3 converts the image signal for variable-speed reproduction using only I-pictures which can be independently decompressed from the compressed image signals input from the compression processor 2. It is generated and output to the data multiplexing unit 4.

The data multiplexing unit 4 multiplexes the image signal input from the compression processing unit 2 or the variable speed reproduction data generation unit 3 with audio, subcodes, other system data, and the like. It is output to the error correction code adding section 5 as a coded signal.

The error correction code adding section 5 adds an error correction code to the multiplexed signal input from the data multiplexing section 4 and
The signal is output to a SYNC / ID (Synchronized Signal / Identified Number) adding unit 6. The SYNC / ID adding unit 6 adds a synchronization signal (sync) and an ID to the input signal (sync block) and outputs the signal to the recording amplifier 7. The ID includes a Synchronized Block Number (hereinafter abbreviated as SB No.) composed of a number indicating the number of a sync block in the track, and a track number (Trac) in which the signal is recorded.
k Number: Tr No.). Generally, the recording of a digital signal is performed by a sync block (Synchr).
This is performed in units of onized Block (hereinafter abbreviated as SB). Therefore, the ID including the SB No. and the Tr No. is used as an address for writing to the buffer memory.

The recording amplifier 7 amplifies the signal input from the SYNC / ID adding section 6 and outputs the amplified signal to the rotary head 8. The rotary head 8 records the signal input from the recording amplifier 7 on the magnetic tape 35 (FIG. 3).

Next, with reference to FIG. 3, the configuration of a reproduction system for an image signal will be described.

The rotary head 8 reads a signal recorded on the magnetic tape 35 and outputs the signal to the reproducing amplifier 21. The reproduction amplifier 21 amplifies the signal input from the rotary head 8 and outputs the amplified signal to the SYNC / ID detection unit 22 and the RF (Radio Frequency) signal position detection unit 30.

The SYNC / ID detector 22 is a signal (sync block) that has just been read and is input from the reproduction amplifier 21.
The Tr No. and the SB No. included in the ID are detected and output to the microcomputer 31 and the image signal is output to the error correction unit 23. The SYNC / ID detection unit 22 stores the SB No. of the image signal for variable-speed reproduction in a built-in memory in advance, and converts the SB number of the image signal for variable-speed reproduction from the image signal input from the reproduction amplifier 21. When No. is detected, a data position detection pulse is generated and output to the microcomputer 31.

The error correction section 23 performs an error correction process on the signal input from the SYNC / ID detection section 22 and, at the time of normal reproduction, converts the error-corrected signal into a data separation processing section 24.
Output to At the time of variable-speed reproduction, the error correction unit 23 outputs the error-corrected signal to the variable-speed reproduction memory 25.

The data separation processing section 24 separates the voice, subcode, and other system data contained in the input signal, outputs the voice to a processing circuit (not shown), The data is output to the microcomputer 31. The image signal is output to the terminal 26a of the switch 27. During normal playback, switch 27
Is controlled to be connected to the terminal 26a. Therefore, at this time, the data separation processing unit 24 outputs the image signal to the decompression processing unit 28.

The variable speed reproduction memory 25 is a buffer memory used at the time of variable speed reproduction, and temporarily stores the variable speed reproduction image signal input from the error correction unit 23,
The data is read out and output to the terminal 26b of the switch 27. The variable speed reproduction memory 25 temporarily stores the input image signal and reads it out at a frame cycle.
There are two types, a type that reads out each time an image signal of a frame is stored, and either type.

At the time of variable speed reproduction, the switch 27
It is controlled to be connected to the terminal 26b. Therefore, at this time, the variable speed reproduction memory 25 reads out the variable speed reproduction image signal, and, through the switch 27,
Output to

The decompression processing unit 28 decompresses the image signal compressed by the MPEG system input through the switch 27, performs an inverse DCT transform, and performs a D / A (Digital / Analog) converter 29. Output to The D / A converter 29 converts the input image signal from a digital signal to an analog signal, and outputs it as an original image signal.

The RF signal position detecting section 30 includes a reproducing amplifier 21
An RF position detection pulse indicating the data position of the read image signal is generated based on the input RF signal, and is output to the microcomputer 31. The microcomputer 31 includes a SYNC / ID detector 22, an RF signal position detector 3,
0, based on various signals input from the capstan motor rotation detection unit 33 and the head switching pulse generation unit 38, a PWM for controlling the rotation speed of the capstan motor 34 that drives the capstan that transfers the magnetic tape 35 (FIG. Pul
se Width Modulation) signal is generated and output to the driver 32. The driver 32 is a microcomputer 31
The rotation of the capstan motor 34 is controlled based on the input PWM signal.

The head switching pulse generator 38 detects the rotation of the two rotary heads 8 provided on the drum 36 based on the rotation signal of the drum 36 detected by the drum rotation detector 37.
A pulse indicating which of the rotary heads 8 is currently reading an image signal among the azimuth angles (+ and-azimuth angles are attached) is generated and output to the microcomputer 31.

The RF signal detector 30, the microcomputer 31, the driver 32, the rotation detector 33, the capstan motor 34, and the head switching pulse generator 38
Will be described later with reference to FIG.

Next, the recording operation of the recording system shown in FIG. 2 will be described. The A / D converter 1 converts an input image signal from an analog signal to a digital signal, and
Output to The compression processing unit 2 performs DCT conversion on the image signal input from the A / D converter 1, performs compression processing in the MPEG format, and outputs the result to the variable speed reproduction data generation unit 3 and the data multiplexing unit 4. .

The variable speed reproduction data generation unit 3 generates variable speed reproduction data (I picture data) from the compressed image signal input from the compression processing unit 2 and outputs the data to the data multiplexing unit 4. . The data multiplexing unit 4 multiplexes audio, subcodes, other system data, and the like with the image signal input from the compression processing unit 2 and the variable speed reproduction data generation unit 3, and performs error correction as a multiplexed signal. Output to the sign adding unit 5. The error correction code adding unit 5 adds an error correction code to the multiplexed signal input from the data multiplexing unit 4 and outputs the multiplexed signal to the SYNC / ID adding unit 6.

The SYNC / ID addition unit 6 adds a synchronization signal and an ID to the signal input from the error correction code addition unit 5 in sync block units, and outputs the signal to the recording amplifier 7. The recording amplifier 7 amplifies the signal input from the SYNC / ID adding unit 6,
Output to the rotating head 8. The rotating head 8 records the image signal input from the recording amplifier 7 on the magnetic tape 35 (FIG. 3).

Next, the operation of the reproduction system shown in FIG. 3 during reproduction will be described. The rotating head 8 reads an image signal recorded on the magnetic tape 35 and outputs the image signal to the reproducing amplifier 21.
The reproduction amplifier 21 amplifies the signal input from the rotary head 8, and outputs the amplified signal to the SYNC / ID detector 22 and the RF signal position detector 3.
Output to 0. The SYNC / ID detection unit 22 includes a reproduction amplifier 21
From the input signal, the sync block is detected based on the synchronization signal, and the SB included in the ID of each sync block is detected.
The Tr No. and SB No. are detected and output to the microcomputer 31 and the image signal is output to the error correction unit 23.

The error correction unit 23 performs an error correction process based on the error correction code added to the image signal input from the SYNC / ID detection unit 22. In the case of normal reproduction, the data separation processing unit 24 In the case of variable-speed reproduction, the data is output to the variable-speed reproduction memory 25. In the case of normal reproduction, the data separation processing unit 2
4 separates audio from the input multiplexed signal, outputs it to a decoder (not shown), separates subcodes and other system data, outputs it to the microcomputer 31, and separates image signals. The signal is output to the terminal 26a of the switch 27. In the case of variable-speed playback, the variable-speed playback memory 25 temporarily stores the variable-speed playback image signal input from the error correction unit 23, reads out the image signals to be sequentially played back, and outputs the image signals to the terminal 26b of the switch 27. I do.

The switch 27 is connected to the terminal 2 for normal reproduction.
6a is connected to the terminal 26b in the case of variable speed reproduction. The decompression processing unit 28 is connected to the terminal 26
a, and expands the image signal input from the data separation processing unit 24 via the switch 27 by the MPEG method.
The data is subjected to DCT conversion and output to the D / A converter 29. In the case of variable-speed reproduction, the expansion processing unit 28 performs an inverse DCT transform after performing expansion processing on the variable-speed reproduction image signal input from the variable-speed reproduction memory 25 via the terminal 26b and the switch 27. Output to the D / A converter 29. 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 the converted signal to a television receiver (not shown) or the like to display an image.

On the other hand, the RF signal position detector 30 generates an RF signal position detection pulse from the signal input from the reproduction amplifier 21 and outputs the pulse to the microcomputer 31. The microcomputer 31 includes an RF signal position detection pulse input from the RF signal position detection unit 30, a Tr No., SB No., and data position detection pulse input from the SYNC / ID detection unit 22, and a capstan motor. A PWM signal for controlling the rotation of the capstan motor 34 is generated based on the capstan motor rotation detection pulse input from the rotation detector 33 and output to the driver 32. The driver 32
Based on the input PWM signal, the capstan motor 3
4 is controlled.

Next, referring to FIG.
0, the microcomputer 31, the driver 32, the capstan rotation detector 33, the capstan motor 34, and the head switching pulse generator 38 will be described in detail.

The RF signal envelope detector 51 of the RF signal detector 30 performs an envelope detection process on the RF signal input from the reproduction amplifier 21, and then outputs the processed signal to the comparator 52. The comparator 52 binarizes the input envelope detection signal based on a predetermined threshold and outputs the binarized signal to the time detection unit 62 of the microcomputer 31 as an RF position detection pulse.

That is, as shown in FIG. 5, the two rotary heads 8 are mounted on the side surface of the rotary drum 36 at target positions with respect to the center axis of the drum 36 with a predetermined azimuth angle. (In FIG. 5, the rotary head 8a has a positive azimuth angle, and the rotary head 8b has a negative azimuth angle.) As shown in FIG. 6, on the magnetic tape 35, each band-shaped track (the number assigned to each band-shaped portion indicates a track number, and + and-below each indicate a track number). In this case, a track recorded and reproduced by the rotary head 8a with an azimuth angle of + is shown.
In the case of-, the track recorded and reproduced by the rotary head 8b with an azimuth angle of-is shown). The rotary heads 8a and 8b sequentially reproduce tracks corresponding to the azimuth of each track during normal reproduction. For example, in the case of 9 × speed reproduction, the feed speed of the magnetic tape 35 is higher than that during normal reproduction. Therefore, in the case of the rotary head 8b in which the azimuth angle shown in FIG. 6 is negative, the rotary head 8b moves in the direction of the arrow shown in FIG.

At this time, the rotary head 8b detects a signal recorded on the magnetic tape 35 by alternately straddling a signal having an azimuth angle of + direction and a signal of-direction. Therefore, the RF signal detected by the rotating head 8b becomes a signal as shown in FIG.

In the RF signal as shown in FIG.
For example, assuming that up to a signal reduced by about 6 dB can be reproduced as data, the signal of the reproduced data is represented by FIG.
An intermittent signal as shown in FIG. Therefore, if the signal shown in FIG. 7B can be detected, the data position can be detected. Therefore, the RF signal envelope detector 51 processes the signal shown in FIG. 7A into a waveform signal composed of the envelope (envelope processing), and
A signal (RF envelope detection signal) as shown in (C) is formed and output to the comparator 52. The comparator 52 converts the RF envelope detection signal into, for example, the signal shown in FIG.
The binarization process is performed using the threshold value L1 in FIG.
The microcomputer 31 generates an RF position detection pulse and
Is output to the time detection unit 62. As a result, when the signal shown in FIG.
The waveform of FIG. 7D (= FIG. 7B) to be obtained can be generated.

The SYNC / ID detection section 22 detects the SB No. and Tr No. of the image signal input from the reproduction amplifier 21 and outputs the capstan servo operation section 71 of the microcomputer 31.
(Configured by a program executed by the CPU 61), and when the SB No. of data (sync block for variable-speed reproduction) required for reproduction is detected, a data position detection pulse Output to the detection unit 62.

The CPU (Central) of the microcomputer 31
Processing Unit) 61 is a microcomputer 31
Control the entire operation of
ROM (Read Only Memor) connected to the main bus 201
y) The contents (program) of the capstan servo operation unit 71 stored in 202 are read and executed. In addition, the CPU 61 may be provided with an HDD (Hard Disk Drive) as necessary.
e) Various programs stored in 204 are stored in RAM 2
03 and execute it. Further, the CPU 61 reads the 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 into the RAM 203 as necessary, and executes the programs.

The time detecting section 62 includes the RF signal position detecting section 30
The time data of the rising edge or the falling edge of the RF position detection pulse input from the input unit and the data position pulse input from the SYNC / ID detection unit 22 are generated, and the capstan servo operation unit 71 executed by the CPU 61 respectively. Output to The time detection unit 62 actually has a counter that circulates at a relatively long interval, and outputs a counter value at the time when a pulse edge is input to the CPU 61.
1 uses the input counter value as time information for calculation. In FIG. 4, the time data A is
Time data of the rising edge or the falling edge of the RF position detection pulse is shown, and time data B shows the time data of the rising edge of the data position detection pulse.

The PWM generation unit 63 subjects the output data (signal) for controlling the rotation of the capstan motor 34 input from the capstan servo operation unit 71 to pulse width modulation processing (PW).
M: Pulse Width Modulation) and outputs to the driver 32 as a PWM output. The frequency divider 64 generates a pulse waveform in which the capstan motor rotation detection pulse input from the capstan motor rotation detection unit 33 is divided by n, and outputs the pulse waveform to the time detection unit 65, for example, for n-times speed reproduction.

The drum rotation detector 37 detects the rotation of the drum 36 and outputs a detection signal to the head switching pulse generator 38. The head switching pulse generation unit 38
A head switching pulse is generated from the signal input from the drum rotation detection unit 37 and output to the time detection unit 65.

The time detector 65 detects time data of the rising edges of the frequency-divided pulse input from the frequency divider 64 and the head switching pulse input from the head switching pulse generator 38. Are output to the capstan servo operation unit 71. The time detection unit 65 is, like the time detection unit 62, actually composed of counter values that circulate at relatively long intervals. In the figure, the time data C is a capstan motor rotation detection pulse corresponding to the frequency divider 64.
Indicates the time data of the rising edge of the frequency-divided pulse, and the time data D indicates the time data of the rising edge of the head switching pulse.

The capstan servo operation section 71 is provided in the ROM 2
02 is a program pre-stored in SYNC / ID
A program for generating a signal for controlling the rotation of the capstan motor 34 from the SB No. and Tr No. input from the detection unit 22 and the time data of the edges of various pulses input from the time detection units 62 and 65. is there.

Next, referring to the control block diagram of FIG.
The capstan servo operation unit 71 will be described.

The capstan servo operation unit 71 includes a speed error operation unit 81, an SB phase error operation unit 82, and a time phase error operation unit 83.

The speed error calculating section 81 detects the actual rotation period (speed) of the capstan motor 34, finds the difference from the reference rotation period, and calculates this as a servo signal of the capstan motor 34.

The speed error calculating section 81 includes a time detecting section 65
The input time data C is input 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 processing to the current processing) and outputs the data to the subtracting unit 102.

The subtraction unit 102 calculates the difference between the time data input from the time detection unit 65 and the time data (the immediately preceding time data) input from the buffer 101 to obtain the current caption. The rotation cycle of the stun motor 34 is calculated and output to the subtraction unit 103.

The subtraction unit 103 calculates the current rotation cycle of the capstan motor 34 input from the subtraction unit 102 and
The difference from the reference rotation cycle of the capstan motor 34 stored in the ROM 202 is obtained, and this difference is output to the adding unit 85 as a speed error.

At the time of variable speed reproduction, the SB phase error calculation unit 82 determines the SB No. at the center of the target data area for variable speed reproduction (the data area in which the image signal of the I picture to be read is recorded) and a predetermined SB No. The difference from the SB No. at the center of the data area captured (detected) in the track is obtained, and the deviation in SB units (SB phase error) is calculated from the difference.

The subtraction unit 111 receives the SB No. at the center of the data area captured by a predetermined track, which is input from the SYNC / ID detection unit 22, and the center of the pre-stored target variable speed reproduction data area. The difference from the SB No. is obtained and output to the gain adjustment unit 112 and the addition unit 114. The details of the subtraction unit 111 will be described later.

The gain adjustment unit 112 adjusts the gain of the signal input from the subtraction unit 111 and outputs the signal to the integration calculation unit 113. The integration operation unit 113 performs an integration operation on the input signal and outputs the resultant signal to the addition unit 114. Adder 114
Represents the signal input from the subtraction unit 111 and the integration operation unit 11
3 are added together and output to the gain adjustment unit 115. Note that the gain adjustment unit 112 and the integration operation unit 11
3, and the adder 114 is an LPF (Low Pass Filter)
And smoothes the signal input from the subtraction unit 111. Gain adjusting section 115 adjusts the gain of the signal input from adding section 114 and outputs the signal to adding section 84.

The time phase error calculating section 83 uses the time data A and B input from the time detecting section 62 at the time of reproduction to detect the time at which the central portion of the captured data area is detected and the target data area. From the difference from the time when the central part of the is detected, a time unit deviation (time phase error) is calculated.

The capture area center position calculator 121 of the time phase error calculator 83 detects the center position of the capture area from the rising edge time of the RF position detection pulse, or the rising edge time and the falling edge time. The calculated time is calculated and output to the subtraction unit 122. The subtraction unit 122 obtains a difference between the time at the center position of the capture area input from the capture area center position calculation unit 121 and the time at the center position of the target variable-speed reproduction data area. Output to the unit 125. Gain adjuster 123, integral calculator 124, and adder 1
Reference numeral 25 denotes an LPF, which smoothes the signal input from the subtraction unit 122 and outputs the signal to the gain adjustment unit 126.
Gain adjusting section 126 adjusts the gain of the input signal and outputs the adjusted signal to switch 127.

When the SB phase error becomes sufficiently small, the switch 127 is turned on, and the gain adjustment unit 126 is turned on.
Is output to the adder 84. The switch 127
The details will be described later.

The adder 84 outputs the SB phase error input from the SB phase error calculator 82 and the time phase error calculator 8
3 is added to the time phase error input from
5 is output.

The adder 85 receives the input from the adder 84
The addition signal of the SB phase error and the time phase error is added to the speed error input from the speed error calculation unit 81 and output to the gain adjustment unit 86.

The gain adjuster 86 adjusts the gain of the added signal of the speed error, the SB phase error, and the time phase error input from the adder 85, and outputs the signal to the integral calculator 87 and the adder 89. The integration operation unit 87, the gain adjustment unit 88, and the addition unit 89 smooth the signal input from the gain adjustment unit 86 and output the smoothed signal to the PWM generation unit 63 as servo data.

Next, referring to the flowchart of FIG.
The processing at the time of variable speed reproduction by the capstan servo operation unit 71 will be described.

In step S1, the speed error calculator 81, the SB phase error calculator 82, and the time phase error calculator 83 calculate the speed error, the SB phase error, and the time phase error, respectively, and calculate the speed error. The calculating unit 81 outputs the speed error to the adding unit 85, and the SB phase error calculating unit 82 and the time phase error calculating unit 83 output the SB phase error and the time phase error to the adding unit 84, respectively, and add them.

Here, the processing of the speed error calculator 81, the SB phase error calculator 82, and the time phase error calculator 83 will be described.

First, the operation of the speed error calculator 81 will be described with reference to the flowchart of FIG. In step S21, the buffer 101 stores the time
The input time data C is stored, and the previously stored time data is output to the subtraction unit 102.
For example, the capstan motor rotation detection pulse input from the capstan motor rotation detection unit 33 is the pulse shown in FIG.
In the case of the pulse shown in FIG.
As shown in (B), a pulse divided by a factor of 10 is generated. The time of the rising edge detected by the time detection unit 65 is time data C. At time t ₂
, The time t ₂ is input to the buffer 101 and the subtraction unit 102, and the buffer 101
Outputs the time data of the time t ₁ stored before to the subtraction unit 102.

In step S22, the subtraction unit 102
Calculates the difference between the time data input from the buffer 101 and the time data input from the time detection unit 65, and sets the difference as the current rotation cycle of the capstan motor and the subtraction unit 103
Output to That is, in this case, the time t ₁ which is the time data input from the buffer 101 and the current time t ₂
The time (t ₂ −t ₁ ), which is the difference between the _two , is output to the subtraction unit 103 as the current rotation cycle of the capstan motor.

In step S23, the subtraction unit 103
Calculates the difference between the reference rotation cycle previously stored in the ROM 202 and the current rotation cycle of the capstan motor (in this case, (t ₂ −t ₁ )), and uses the difference as a speed error in the adding unit 85. Output.

The processing of the speed error calculating section 81 is as follows.
Since it is executed at the rising time of the capstan rotation detection pulse in FIG. 11B, the execution is performed at the rising edge timing of the frequency-divided pulse in FIG. 11B as shown in FIG. 11C. Will be done.

Next, a process in which the SB phase error calculating section 82 calculates the SB phase error will be described with reference to the flowchart of FIG.

In step S31, the subtraction unit 111
Is the center of the data area captured on a given track
SB No. and target SB N stored in ROM 202
o., the gain adjustment unit 112 and the addition unit 1
14 is output.

Here, the processing of the subtraction unit 111 will be described. For example, as shown in FIG. 13, data recorded on the magnetic tape 35 is an MPEG HD VTR (High Def.
It is assumed that the pattern is a pattern for 16 × speed of an inition Video Tape Recorder) format. In the actual pattern,
Although a plurality of identical data are recorded in one reproduction area, the central position of each area is
Only SB shall be shown.

As shown in the figure, a search area for forward / reverse direction in which data for variable speed reproduction is recorded, and a common search area thereof (areas g1 to g4 are a search area for 16 × speed (forward direction), f1 to f4 are -16 × speed search areas (reverse direction), and areas h1 and h2 are common areas.
1, f2, g1, g2, h1) are arranged on three pairs of tracks (Trp0 to Trp2) out of the eight pairs of tracks. This pattern is arranged every 16 tracks.

[0086] Trp is an abbreviation of Track Pair No., which indicates a number assigned to one of two tracks. The two tracks in each pair are distinguished by + and-azimuth angles. In this case, it is assumed that a rotary head 8a having an azimuth angle in the + direction is used. In the figure,
SB No. shall be numbered from the bottom up.

Now, a straight line L11 shown at the center of each track
Servo is performed so that the upper areas h1 and h2 are areas having the target SB No. to be read. That is, if only the SB on the straight line L11 of the track with the azimuth angle of Trp1 added to + can be accurately scanned, it is assumed that a 16 × speed video signal can be stably reproduced.

At this time, assuming that the rotary head 8a scans the line indicated by the scan phase A in FIG. 13, the area a1 is scanned on the track where the azimuth angle of Trp1 is added to +. Will be. Therefore, the difference from the target SB No., that is, the SB phase error is the difference between the SB No. of the area h1 and the SB No. of the area a1.
This difference E is represented by E0 (= h1-a1).

For example, if the rotary head 8a scans the line indicated by the scan phase C, the area c2 is scanned on the track where the azimuth angle of Trp1 is added to +. . Therefore,
The difference E between the target area h2 and the area c2 is -E3
(= H2-c2), which is the SB phase error.

The relationship between the SB phase error and the Trp number at which each line serving as the scan phase intersects the straight line L11 is shown in FIG.
4 (A).

As is clear from FIG. 14A, for example, when the rotary head 8a scans on the line indicated by the scan phase B in FIG. 13, on the track where the azimuth angle of Trp1 is +. Since no portion is scanned by the rotary head 8a, the SB phase error cannot be detected. That is, as shown by the dotted line at the position of Trp5 in FIG. 14A, there is a portion where the SB phase error cannot be detected.

Then, an area b0 for 16 × speed is written in the center of Trp5 located at the center between adjacent Trp1s,
An error is also detected from the difference between the SB No. of this area b0 and each scan phase.

That is, for example, Trp of scan phase A
5, the SB phase error E on scan area A
2 and the area b0, E = K1−E1 (K1
Is the maximum value of E1). Also, the scan phase C
, The areas c1 and b on the scan phase C
From the relationship with 0, E =-(K2-E2) (K2 is E2
Of the maximum). FIG. 14B shows the relationship between the SB phase error when this area b0 is used and the Trp number at which each line serving as the scan phase intersects the straight line L11. At this time, in Trp1 of FIG. 14B, there is no difference from the area b0, so that there is no SB phase error. For this reason, FIG.
Are not continuous for all scan phases.

Therefore, as shown in FIG.
The SB phase error is set by the sum of 4 (A) and FIG. 14 (B). According to the relationship shown in FIG. 14C, the SB phase error is continuously obtained at every scan phase. Therefore, the subtracting section 111 performs the processing shown in FIG.
Will be calculated.
Accordingly, in the subtraction unit 111, in actuality, taking the scan phase A in FIG. 13 as an example, the areas h1 and a1, and
The difference between the SBs of the areas b0 and a2 is calculated, and the sum of the calculation results is output as the SB phase error.

Next, the SB No. at the center of the data area captured on a predetermined track (as described above, a plurality of SBs recording the same data are arranged in the track direction).
The method for obtaining the phase error with the above will be described. For example, as shown in FIG. 15A, the target SB No. TN
(Target No.) is the captured area (SNa (Sta
rt No.a) and ENa (End No.a), the SB phase error Ea is Ea = TN−CNa (Center No.
a) (= TN− (ENa−SNa) / 2). Also,
As shown in FIG. 15B, the area where the TN is captured (SN
b (between Start No. b) and ENb (End No. b)), the SB phase error Eb is Eb = TN−CNb (Center No. b)
(= TN− (ENb−SNb) / 2). Further, as shown in FIG. 15C, the area (SNc
(Between Start No.c) and ENc (End No.c)), the SB phase error Ec is Ec = TN−CNc (Center No.
c) (= TN− (ENc−SNc) / 2). That is, the first SB No. and the last SB No. of the captured area
And the target SB No.
The number of SBs that are different from TN is the SB phase error.

Returning to the description of the flowchart of FIG. In step S32, the gain adjustment unit 112, the integration operation unit 113, and the addition unit 114 smooth the signal of the SB phase error input from the subtraction unit 111 and output the signal to the gain adjustment unit 115.

In step S33, the gain adjustment unit 1
15 adjusts the gain of the input SB phase error signal and outputs the signal to the adder 84.

FIG. 16 is a time chart for explaining the processing timing of the SB phase error calculating section 82. FIG.
(A) and (B) correspond to (B) and (C) in FIG. 11 and are shown for comparison. FIG. 16 (C)
Indicates a head switching pulse, and FIG.
Indicates an RF position detection pulse.

For example, when the rotating head 8a scans the track recorded on the magnetic tape along the scan phase A in FIG. 13, the scan is performed at the time t at the rising edge of the head switching pulse shown in FIG. It will start from ₁₁ . Then, as shown in FIG. 16 (D), at time t ₁₂ to t ₁₃ of the RF position detection pulse, so that the area a1 of FIG. 13 is detected. The SYNC / ID detection unit 22 immediately starts scanning the area h1 (at time t1).
At the timing of ₁₃ immediately after), the SB No. in the center position of the area a1, and sent to the SB phase-error calculating unit 82 of the capstan-servo operation unit 71, at time t _'13, S
The B phase error calculation unit 82 performs an SB phase error calculation process. Similarly, at time t ₁₄ to t _15, it means that the area a2 in FIG. 13 is detected, as in the case of scanning an area a1, SYNC / ID detection unit 22, immediately after the area a2 is scanned at a timing (immediately after time t _15), transmits the SB No. in the center position of the area a2, at time t _'15, SB phase-error calculating unit 8
2 executes an SB phase error calculation process.

The SB phase error calculating section 82 may perform the processing at the above timing. For example, as shown in FIG. 16F, the SB phase error calculating section 82 reads the positions of the areas a1 and a2. After that, each SB No. is stored in a buffer of the SYNC / ID
_16, and collectively transmitted, may be such that the process from the time t _'16.

In the former case, the SB phase error calculation unit 82
Each time the time data is input, the interrupt processing is forced, so the processing time may be longer,
The processing can be simple. On the contrary,
In the latter case, it is necessary for the SB phase error calculation unit 82 to provide a buffer in the hardware (in the SYNC / ID detection unit 22), but, for example, among the processing timings of the CPU 31, the timing with the lowest load is selected. Since processing can be performed, processing time can be efficiently improved.

Next, the processing of the time phase error calculation section 83 will be described with reference to the flowchart of FIG.

In step S41, the capture area center position calculation unit 121 determines, for example, the time t2 in FIG.
At timings such as 1, t23, t25, t27, t29, t31,... Based on the rising edge time data A (rising edge time data of the RF position detection pulse) input from the time detection unit 62, The time for detecting the center position of the capture area is calculated. Note that FIG.
18A shows an RF signal, FIG. 18B shows an RF envelope signal, and FIG. 18C shows an RF position detection pulse.

That is, for example, the RF shown in FIG.
Time t ₄₁ is assumed to have been entered as the time data A of the rising edge of the position detection pulses. Now, assuming that the track width and the width of the rotary head 8a are the same, the time Tc required for scanning one track (FIG. 19A)
In the time between times t ₄₁ to t ₄₃₎ is defined as follows.

Tc = (time of one scan) / (n ± 1) (n: double speed number (feed is-, return is +)) (1)

The rotating head 8a passes through the center of the scan area on the track at an intermediate time during the period spent scanning one track. Thus, half the time period required for scanning of one track, the summed time to time t _41, the rotary head 8a will pass through the center position of the captured area. The capture area center position calculation unit 121 calculates the time at the center position as described above, and outputs the time to the subtraction unit 122.

In step S42, the subtraction unit 122
Calculates the difference between the time of the capture area center position input from the capture area center position calculation unit 121 and the time at which the target variable speed reproduction data area center position is detected, and obtains a time phase error as the gain adjustment unit 123. And adder 1
25.

[0108] That is, as shown in FIG. 19 (B), at time t _44, when the data position detection pulse speed playback data to be a target is detected, a time phase error is calculated as follows .

E = Tc / 2−Td0 = Tc / 2− (t ₄₃ −t ₄₁ ) (2)

Note that Td0 represents the difference between the rising edge of the RF position detection pulse and the timing of the rising edge of the data position detection pulse.

However, this corresponds to FIG.
As shown in (B), when the time of the rising edge of the RF position detection pulse is between the rising edge and the falling edge of the data position detection pulse, that is, the rotating head 8a can read the image signal. This is the case where a data position detection pulse is generated during the period. For example, as shown in FIGS.
If a data position detection pulse is detected during a period during which the image signal cannot be read, the time phase error is calculated as follows.

E = Tc / 2 + Td2 = Tc / 2 + (t ₄₆ −t ₄₃ ) (3)

However, only 1 can be used for the actual calculation.
Since it becomes the time data of the immediately preceding rising edge, the actual calculation is as follows.

E = Tc / 2 + Td2 = Tc / 2 + (2 × Tc−Td1) = 5/2 × Tc + Td1 = 5/2 × Tc + (t ₄₃ −t ₄₄ ) (4)

As described above, the processing varies depending on the positional relationship between the rising edge time and the falling edge time of the RF position detection pulse and the rising edge time of the data position detection pulse.

The difference between the processes is that the RF position detection pulse (FIG. 19A) having an advanced phase as viewed from the rising edge time of the data position detection pulse (FIG. 19B).
It is necessary to divide the calculation depending on whether to take the difference from the time at the center of the RF signal or the difference from the time at the center of the RF position detection pulse (FIG. 19C) having a delayed phase.

Since the time phase error is the difference from the time at the center of the RF position detection pulse having a close phase as seen from the rising edge time of the data position detection pulse, 3 / 2Tc
In the case of ≧ Td (Td is the difference from the time at the center of the RF position detection pulse having a close phase when viewed from the rising edge time of the data position detection pulse) (in the case of FIG. 19A), use equation (1) And when 3 / 2Tc <Td (FIG. 19)
(C), equation (4) is used.

Here, the description returns to the flowchart of FIG. In step S43, the gain adjustment unit 123,
The integration operation unit 124 and the addition unit 125 include the subtraction unit 1
22 to smooth the time phase error signal input from
Output to gain adjustment section 126.

The gain adjuster 126 adjusts the gain of the input time phase error signal and outputs a signal to the adder 84 via the switch 127.

Here, the description returns to the flowchart of FIG. In step S2, the adding unit 84 adds the SB phase error and the time phase error, and outputs the result to the adding unit 85 as a phase error.

In step S3, the adding section 85 adds the speed error from the subtracting section 013 to the phase error from the adding section 84 and outputs the result to the gain adjusting section 86. The gain adjustment unit 86 adjusts the gain of the input signal and outputs the signal to the integration operation unit 87 and the addition unit 89. Integral operation unit 8
7. The gain adjustment unit 88 and the addition unit 89 constitute an LPF, smooth the signal input from the gain adjustment unit 86, output the signal to the PWM generation unit 63, and return to the process of step S1 again. The process is repeated.

Note that the SB phase error calculation section 82 controls the switch 127 as follows. That is, since the information of the Tr No. is not input to the time phase error calculation unit 83, the target SB No. can be specified by the time phase error, but the Tr No cannot be specified. As shown in FIG. 19, the time phase error is obtained using an RF position detection pulse having a phase close to the data position detection pulse, and is not necessarily a target Tr.
It is not obtained using the RF position detection pulse corresponding to No.

On the other hand, since Tr No is input from the SYNC / ID detector 22 to the SB phase error calculator 82, the SB phase error corresponding to the current track can be specified. Therefore, the SB phase error calculation unit 82 calculates the SB phase error as shown in Trp1 in FIG.
The switch 127 is turned off until the phase error becomes sufficiently small (for example, becomes 0).

Then, as shown by Trp1 in FIG. 14C, for example, when the SB phase error becomes 0, the SB phase error calculation section 82 turns on the switch 127 and sets the gain adjustment section. 115 to reduce the output of the SB phase error.

That is, since the SB phase error is controlled in SB units, when the SB phase error becomes 0, an error may occur at a level lower than the SB unit.
At the SB level, there will be no errors. Therefore, the accuracy can be further improved by compensating for errors within SB using the time phase error.

In place of the switch 127, for example,
Using the gain adjustment unit 126, the gain is set to 0 when the SB phase error is not 0, and the gain is set to 1 when the error of the SB unit is 0, and the output is made. You may make it control.

In the above example, the time phase error is calculated using only the rising edge of the RF position detection pulse. However, both the rising edge and the falling edge of the RF position detection pulse are used. May be used to calculate. In this case, FIG.
At time t _21, t _22, t ₂₃ time of the rising and falling edges of ... the (D), the time detecting unit 62 outputs the time data A to the time phase error calculating unit 83.

Using both edges of the RF position detection pulse,
When calculating the time phase error, as in the case of using the rising edge, the time at the center of both edges of the RF position detection pulse of the advanced phase is used, as seen from the rising time of the data position detection pulse, or It is necessary to divide the calculation depending on whether to use the time at the center of both edges of the RF position detection pulse having a delayed phase. Therefore, when both edges of the RF position detection pulse are used, a flag for dividing the calculation is provided.

The flag is set from the time of the rising edge of the data position detection pulse to the time of the subsequent falling edge of the first RF position detection pulse, and the calculation is divided by this flag.

For example, as shown in FIG. 20A, the time t within the period from the time t _{61 to} the time t ₆₂ of the RF position detection pulse.
_71, if the data position detection pulse is detected shown in FIG. 20 (B), as shown in FIG. 20 (C), the flag is generated over a period of time t ₇₁ to t _62.

An RF position detecting pallet as shown in FIG.
Time of the falling edge of the ₆₂), The flag is
You will be standing. At this time, the capture area center position
The calculation unit 121 calculates the time phase error as follows.
You.

E = (t ₆₁ + t ₆₂ ) / 2−t ₇₁ (5)

Further, the RF position detection as shown in FIG.
When an outgoing pulse is detected, as shown in FIG.
When the data position detection pulse is at time t₉₂And time t₉₃Time between
Time t ₇₁At time t₇₁In FIG.
The RF position detection pulse shown in FIG.
Image signal cannot be read
Therefore, the time t of the next RF position detection pulse₈₁(= T₉₃)
Or t₉₄The period flag up to this point will rise.

At this time, the center time (t _{101) of the} period during which the image signal cannot be read by the rotary head 8a.
_{= (T 92 + t 93)} / 2) is changed is calculated by determining whether a prior detection time t ₇₁ of the data position detection pulse.

[0135] When the time t ₇₁ is the detection time of the data position detection pulse is before time t _101, the time phase error is calculated as follows.

E = (t ₉₁ + t ₉₂ ) / 2−t ₇₁ (6)

[0137] Also, when the time t ₇₁ is the detection time of the data position detection pulse is after the time t _101, the time phase error is calculated as follows.

E = (t ₉₃ + t ₉₄ ) / 2−t ₇₁ (7)

[0139] In the case of calculating using equation (5), for example, when 20 of (A), the processing will be executed at time t _62. Also, when using equation (6),
The process is executed at a time t _93. Further, equation (7)
, For example, in the case of FIG.
The process is executed at a time t _94.

As a result, the time phase error can be calculated by calculating the time phase error using both edges of the RF position detection pulse, as in the case of calculating only the time of the rising edge. When viewed from the edge time, the difference is calculated as a difference from the center time of the RF position detection pulse at a close position.

In the calculation of the time phase error, RF
When only the rising edge of the position detection pulse is used, the interrupt processing in the processing is performed only at the time of the rising edge, so that there is an advantage that the load on the microcomputer 31 is light. However, since the time width for detecting the data area is fixed, there is a disadvantage that an error is likely to occur in the calculation.

On the other hand, in the calculation of the time phase error,
When both the rising edge and the falling edge of the position detection pulse are used, there is a merit that an error hardly occurs because the time width for detecting the data area is securely calculated, but the load on the microcomputer 31 becomes heavy. There is a disadvantage.

In the above description, the data position detection pulse is detected by the SYNC / ID detection unit 22. For example, as shown in FIG. 16E or FIG. timing (for example, time t _13, t
₁₅ , t ₁₆ ) has a fixed relation to the head switching pulse shown in FIG. Therefore, the data position detection pulse has a fixed time from the rising edge time of the head switching pulse, for example. Therefore, instead of the data position detection pulse, a predetermined time may be set with respect to the time of the rising edge of the head switching pulse.

The method of using both the errors of the SB phase error calculating section 82 and the time phase error calculating section 83 has been described above. However, for example, the target data is recorded a plurality of times, and the trace error is large. If this is also allowed, only the SB phase error calculated by the SB phase error calculator 82 may be used.

In the above description, the capstan servo operation section 71 has been described as a program shown in a control block diagram as shown in FIG. 8, but the hardware corresponding to the control block diagram in FIG. Then, it may be processed.

As described above, it is possible to stably reproduce the image signal recorded on the tape-shaped recording medium even at the time of variable-speed reproduction.

The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, a program constituting the software may be executed by a computer built into dedicated hardware or by installing various programs to execute various functions. It is installed from a recording medium to a possible general-purpose personal computer or the like.

As shown in FIG. 4, this recording medium is not limited to the HDD 204 in which the program is recorded, but is also provided separately from the computer in order to provide the user with the program. Disk 211 (including a floppy (registered trademark) disk),
Optical disk 212 (CD-ROM (Compact Disk-Read Only Me)
mory), a DVD (including a Digital Versatile Disk), a magneto-optical disk 213 (including an MD (Mini-Disk)), or a package medium including a semiconductor memory 214 (including a Memory Stick).

In this specification, the step of describing a program recorded on a recording medium is not limited to processing performed in chronological order according to the described order, but is not necessarily performed in chronological order. , And processing executed in parallel or individually.

[0150]

According to the image reproducing apparatus and method of the present invention and the program of the recording medium, of the information recorded on the tape recording medium, the position of the information for variable speed reproduction on the tape recording medium. Is stored as a target position, the information recorded on the tape-shaped recording medium is read, the position of the read information on the tape-shaped recording medium is detected as a read position, and the stored target position and the detected read position are detected. The difference between the target position and the read position is detected based on the difference between the target position and the read position, so that the feed speed of the tape-shaped recording medium is controlled, so that the image signal recorded on the tape-shaped recording medium is Reproduction can be performed stably even during variable-speed reproduction.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating compression in the MPEG system.

FIG. 2 is a diagram showing a configuration of an embodiment of a digital video tape recorder to which the present invention is applied.

FIG. 3 is a diagram showing a configuration of an embodiment of a digital video tape recorder to which the present invention is applied.

FIG. 4 is a configuration diagram around the microcomputer of FIG. 3;

FIG. 5 is a diagram illustrating the drum of FIG.

FIG. 6 is a diagram illustrating an operation in which a rotating head reads an image signal recorded on a magnetic tape.

FIG. 7 is a diagram illustrating signals generated by the RF signal position detection unit in FIG. 4;

FIG. 8 is a control block diagram of a capstan servo operation unit of FIG. 4;

FIG. 9 is a flowchart illustrating processing of a capstan servo operation unit.

FIG. 10 is a flowchart illustrating a process of a speed error calculation unit.

FIG. 11 is a timing chart illustrating a process of a speed error calculation unit.

FIG. 12 is a flowchart illustrating a process of an SB phase error calculation unit.

FIG. 13 is a diagram illustrating the processing of the SB phase error calculation unit.

FIG. 14 is a diagram illustrating a process of an SB phase error calculation unit.

FIG. 15 is a diagram illustrating a process of an SB phase error calculation unit.

FIG. 16 is a timing chart illustrating a process of an SB phase error calculation unit.

FIG. 17 is a flowchart illustrating processing of a time phase error calculation unit.

FIG. 18 is a diagram illustrating a process of a time phase error calculation unit.

FIG. 19 is a diagram illustrating processing of a time phase error calculation unit.

FIG. 20 is a diagram illustrating processing of a time phase error calculation unit.

[Explanation of symbols]

30 RF signal position detector, 31 microcomputer, 32 driver, 33 capstan motor rotation detector, 34 capstan motor, 35 magnetic tape,
36 drum, 37 drum rotation detector, 38 head switching pulse generator, 51 RF envelope detector, 5
2 Comparator, 61 CPU, 62 Time detector, 6
3 PWM generator, 64 divider, 65 time detector, 7
1 Capstan servo operation unit, 81 Speed error operation unit, 82 SB phase error operation unit, 83 Time phase error operation unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/92 H04N 5/92 H

Claims (10)

[Claims] 1. An image reproducing apparatus for performing variable-speed reproduction of information recorded on a tape-shaped recording medium, wherein, among the information recorded on the tape-shaped recording medium,
A target position storage unit that stores a position of the variable speed reproduction information on the tape-shaped recording medium as a target position; a reading unit that reads information recorded on the tape-shaped recording medium; and the reading unit. Reading position detecting means for detecting a position of the read information on the tape-shaped recording medium as a reading position; the target position stored by the target position storing means; and the reading detected by the reading position detecting means. Difference detection means for detecting a difference from a position, and feed speed control means for controlling a feed speed of the tape-shaped recording medium based on a difference between the target position and the reading position detected by the difference detection means. An image reproducing apparatus comprising: 2. The target position storage means stores the target position as a track number and a sync block number of the tape-shaped recording medium. The read position detection means stores the read position in the tape-shaped recording medium. The difference detecting means detects a difference between the target position and the read position from a difference between the track number and the sync block number of the target position and the read position. The image reproducing apparatus according to claim 1, wherein: 3. A target position detecting means for detecting the target position stored by the target position storing means from the tape-shaped recording medium, and detecting a time at which the target position is detected by the target position detecting means. Further comprising: a target position detection time detecting unit that detects the time when the reading position is detected by the reading position detecting unit; and the difference detecting unit includes the target position detection time detecting unit. 2. The image reproducing apparatus according to claim 1, wherein a difference between the target position and the reading position is detected from a difference between the time detected by the first detecting unit and the time detected by the reading position detecting time detecting unit. . 4. The reading position detection time detecting means,
The read position is detected by the read position detecting means by using one or both of a rising edge and a falling edge of a pulse signal obtained by binarizing the envelope signal of the reproduction RF signal using a predetermined threshold. The image reproducing apparatus according to claim 3, wherein a time at which is detected is detected. 5. The target position and the read position detected from the difference between the track number and the sync block number of the target position and the read position detected by the difference detection unit. And the difference between the target position and the reading position detected from the difference between the time detected by the target position detection time detecting means and the time detected by the reading position detection time detecting means. 4. The image reproducing apparatus according to claim 3, wherein a feed speed of the tape-shaped recording medium is controlled based on one or both of them. 6. A head switching pulse reference target position detection time detecting means for detecting a time at which the target position is detected based on a rising edge or a falling edge of the head switching pulse signal, and an envelope of the reproduction RF signal. Reading position detection time detecting means for detecting a time at which the reading position is detected by the reading position detecting means based on a pulse signal obtained by binarizing the signal using a predetermined threshold value; Means for detecting a difference between the target position and the reading position from a difference between a time detected by the head switching pulse reference target position detection time detecting means and a time detected by the reading position detection time detecting means. The image reproducing apparatus according to claim 1, wherein: 7. The reading position detection time detecting means,
The reading position is detected by the reading position detecting means by using one or both of the rising edge and the falling edge of the pulse signal obtained by binarizing the envelope signal of the reproduction RF signal using a predetermined threshold. The image reproducing apparatus according to claim 6, wherein the detected time is detected. 8. The target position and the reading position detected from the difference between the track number and the sync block number of the target position and the reading position, respectively, which are detected by the difference detecting unit. And the difference between the target position and the read position detected from the difference between the time detected by the head switching pulse reference time detection means and the time detected by the read position detection time detection means. The image reproducing apparatus according to claim 6, wherein a feed speed of the tape-shaped recording medium is controlled based on one or both of them. 9. An image reproducing method of an image reproducing apparatus for performing variable-speed reproduction of information recorded on a tape-shaped recording medium, wherein, among the information recorded on the tape-shaped recording medium,
A target position storing step of storing a position of the variable speed reproduction information on the tape-shaped recording medium as a target position; a reading step of reading information recorded on the tape-shaped recording medium; A reading position detecting step of detecting a position on the tape-shaped recording medium of the information read in the processing as a reading position; a target position stored in the processing of the target position storing step; and a processing of the reading position detecting step A difference detection step of detecting a difference between the read position and the read position, and feeding of the tape-shaped recording medium based on a difference between the target position and the read position detected in the processing of the difference detection step. A feed speed control step of controlling a speed. 10. A program for controlling an image reproducing apparatus that performs variable speed reproduction of information recorded on a tape-shaped recording medium, wherein the information is recorded on the tape-shaped recording medium.
A target position storage control step for controlling storage of the position for the variable speed reproduction information on the tape-shaped recording medium as a target position; and a reading control for controlling reading of information recorded on the tape-shaped recording medium. A control step; a read position detection control step of controlling detection of information read in the processing of the read control step as a read position of a position on the tape-shaped recording medium; and storage in the processing of the target position storage control step. A difference detection control step for controlling detection of a difference between the target position thus set and the read position detected in the processing of the read position detection control step; and the target detected in the processing of the difference detection control step. A feed speed control for controlling a feed speed of the tape-shaped recording medium based on a difference between a position and the reading position; And a computer-readable recording medium storing a computer-readable program.