JPH1031804A - Rotating head recording / reproducing device - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a rotary head recording / reproducing apparatus which can easily synchronize a rotary head even when recording / reproducing by switching between an analog video signal and a digital video signal. It is in. A recording / reproducing circuit for recording or reproducing a signal, a rotary head for recording or reproducing a recording signal generated by the recording / reproducing circuit on a magnetic recording medium, and a rotation of the rotary head In a rotary head recording / reproducing apparatus including a rotary head control circuit for controlling the rotation, a synchronization means for synchronizing the recording / reproducing processing timing of the recording / reproducing circuit with the rotation phase of the rotary head is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head recording / reproducing apparatus for recording / reproducing signals on a magnetic tape using a rotary head, and more particularly to a recording / reproducing apparatus for recording / reproducing both analog video signals and digital video signals. It is.

[0002]

2. Description of the Related Art A digital signal recording apparatus for recording a digital video signal on a magnetic tape by using a rotary head has been developed.
It is described in JP-A-5-174496.

[0003]

However, no consideration has been given to the dual use of recording and reproduction of analog video signals. When recording and reproducing an analog video signal by the rotary head, the rotation of the rotary head is synchronized with a vertical synchronization signal in the recorded video signal at the time of recording and with a reference signal obtained by dividing the reference clock of the analog recording and reproducing circuit at the time of reproduction. On the other hand, when recording and reproducing digital video signals, the rotation of the rotary head is synchronized with a reference signal obtained by dividing the reference clock of the digital recording and reproducing circuit for both recording and reproduction. Therefore, when switching between analog and digital,
Since the reference signal of the rotary head is also switched, there is a problem that it takes time to resynchronize. Also,
In the case of analog recording and reproduction, the relationship between the azimuth of the even track and the odd field and the azimuth of the recording track does not need to be the same. Has been stipulated. Therefore, when a control circuit for recording / reproducing an analog signal which does not particularly control the relationship between the signal and the azimuth of the track is used, the relationship between the signal and the azimuth of the track may not match during digital recording / reproduction. As a result, there is a problem that recording and reproduction cannot be performed normally.

It is an object of the present invention to provide a rotary head recording / reproducing apparatus which can easily synchronize a rotary head even when recording / reproducing by switching between an analog video signal and a digital video signal.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a recording / reproducing circuit for recording or reproducing a signal, and a rotary head for recording or reproducing a recording signal generated by the recording / reproducing circuit on a magnetic recording medium. In a rotary head recording / reproducing apparatus comprising a rotary head control circuit for controlling the rotation of the rotary head, this can be achieved by providing a synchronization means for synchronizing the recording / reproducing processing timing of the recording / reproducing circuit with the rotational phase of the rotary head.

[0006]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a rotary head recording / reproducing apparatus according to the present invention. FIG. 1 shows an apparatus that is used for both recording and reproduction. Of course, the same applies when recording and reproduction are independent. 10
0 is a rotating head, 101 is a capstan, 102 is a switching circuit for switching between the two heads A and B on the rotating head 100, 103 is a switching circuit for switching recording / reproducing signals, and 104 is recording / reproducing of digital signals. A digital signal recording / reproducing circuit for performing processing; 105, a timing generating circuit for generating timing for recording / reproducing digital signals; 106, an oscillation circuit for generating a reference clock for recording / reproducing digital signals; 107, recording / reproducing of analog signals An analog signal recording / reproducing circuit for performing processing; 116, an oscillation circuit for generating a reference clock for recording / reproducing an analog signal; 108, a rotary head control circuit for controlling the rotation of the rotary head; 109, a reference signal for the rotary head control circuit; A switching circuit 110 for switching controls a recording / reproducing mode or the like. The control circuit such as a black processor,
Reference numeral 111 denotes a key input circuit for switching between analog and digital, and setting for recording or reproduction, and 112 denotes a magnetic tape,
Reference numeral 17 denotes a detector for detecting the rotational position of the rotary head.

First, recording and reproduction of an analog video signal will be described. At the time of recording / reproducing an analog signal, the switching circuits 103 and 109 are switched to the analog signal recording / reproducing circuit 107 side.

At the time of recording, an analog video signal is input from an input terminal 114 to an analog signal recording / reproducing circuit 107. Then, the data is recorded by the rotary head 100 via the switching circuit 103 and the switching circuit 102. Also, at this time,
The analog signal recording / reproducing circuit 107 extracts a vertical synchronizing signal from the input analog video signal and outputs it to the rotary head control circuit 108 as a reference signal for rotary head control. FIG. 7 shows a rotary head control circuit 1 for analog recording.
It is an operation timing chart of 08. Rotating head control circuit 1
In step 08, control is performed such that the reference signal and the head position signal detected by the detector 117 have a predetermined phase α.
At the same time, a head switching signal is generated. The head switching signal selects, for example, the head A at the L level and selects the head B at the H level. The switching circuit 102 is switched by the head switching signal, and recording is sequentially performed by the heads A and B as shown in FIG.

The control by the rotary head control circuit 108 at the time of reproduction is the same as that at the time of recording, except that the reference signal is changed to a signal generated by the oscillation circuit 116.
That is, the signals sequentially reproduced by the heads A and B are output to the output terminal 11 via the analog recording / reproduction circuit 107.
5 is output.

The number of rotations of the rotary head 100 during analog recording and reproduction is synchronized with the frame period of the analog video signal. For example, 30 / 1.001 Hz.

Next, recording and reproduction of a digital video signal will be described. When recording and reproducing digital video signals,
The switching circuits 103 and 109 are switched to the digital signal recording / reproducing circuit 104 side.

FIG. 3 shows a recording pattern of one track. 3 is a subcode recording area for recording subcodes such as time information and program information, 7 is a data recording area for recording a digital compressed video signal, 2 and 6 are preambles of the respective recording areas, and 4 and 8 are respective recording areas. The postamble of the area, 5 is the gap between the recording areas, and 1 and 9 are the margins at the track ends. Of course, digital signals other than digital compressed video signals and audio signals may be recorded in the recording areas 3 and 7. Further, a digital compressed audio signal may be recorded in the area 7 together with the digital compressed video signal.

FIG. 4 shows a block configuration of each area. FIG.
(A) is a block configuration of the data recording area 7. 2
0 is a synchronization signal, 21 is ID information, 22 is data, and 23 is a parity (C1 parity) for the first error detection and correction.
It is. For example, the synchronization signal 20 has 2 bytes and ID information 2
1 is 3 bytes, data 22 is 99 bytes, parity 23
Is composed of 8 bytes, and one block is composed of 112 bytes. FIG. 4B shows a block configuration of the subcode recording area 12. In the block of the subcode recording area, the synchronization signal 20 and the ID information 21 are shown in FIG.
2A, the data 22 is composed of 19 bytes, and the parity 23 is composed of 4 bytes.
It is composed of 28 bytes, which is 1/4 of the block of (a).

FIG. 5 shows the structure of the ID information 21. 31
Is a sequence number, 32 is a track address, 33 is 1
A block address 35 in the track is a sequence number 31, a track address 32 and a block address 33.
This is a parity for detecting an error of. The block address 33 is an address for identifying a block in each recording area. For example, in the data recording area 7,
In the 335 subcode recording area 3, it is 0 to 15. The track address 32 is an address for identifying a track. For example, by changing the address in units of one track or two tracks and setting it to 0 to 5 or 0 to 2, 6 tracks can be identified. . The sequence number 31 is changed, for example, in units of six tracks identified by the track address 32, and is set to 0 to 11, so that 72 tracks can be identified. By synchronizing the track address with a cycle of a second error correction code described later, processing at the time of recording and identification at the time of reproduction can be facilitated.

FIG. 6 shows the structure of data of one track in the data recording area 7. Note that the synchronization signal 20 and the ID information 21 are omitted. The data recording area 7 is composed of, for example, 336 blocks.
Data 41 is recorded in the block, and a second error correction code (C2 parity) 43 is recorded in the next 30 blocks. For example, the C2 parity 43 divides the data of 306 blocks × 6 tracks into 18 pieces in units of 6 tracks,
10 blocks of C2 parity are added to 2 blocks.
For example, a Reed-Solomon code may be used as the error correction code. Each block of 99-byte data is composed of a 3-byte header 44 and 96-byte data 41.

At the time of recording, a digital video signal is input from the input / output terminal 113 to the digital signal recording / reproducing circuit 104. Then, the switching circuit 103 and the switching circuit 102
Is recorded by the rotating head 100 via the. At the time of reproduction, signals sequentially reproduced by the heads A and B are supplied to the input / output terminal 11 via the digital signal recording / reproduction circuit 104.
3 is output.

At the time of digital video signal recording and reproduction, the timing generation circuit 106 generates a reference signal of the rotary head control circuit 108 in synchronization with the processing timing of the digital signal processing circuit 104 with reference to the reference clock generated by the oscillation circuit 106. . Rotating head control circuit 1
In step 08, similarly to the recording and reproduction of the analog video signal, control is performed such that the reference signal and the head position signal detected by the detector 117 have a predetermined phase α. At the same time, a head switching signal is generated to switch the switching circuit 102.

FIG. 8 shows the configuration of the timing generation circuit 105. 401 is a decode circuit, and 402 is an edge detection circuit. The decoding circuit 401 generates a timing signal serving as a reference for the operation of the digital signal recording / reproducing circuit 104 and a reference signal for controlling the rotary head based on the reference clock generated by the oscillation circuit 106 input from the input terminal 405. A timing signal serving as a reference for the operation of the digital signal recording / reproducing circuit 104 is output from the output terminal 406 to the digital signal recording / reproducing circuit 104. Further, a reference signal for controlling the rotary head is output from the output terminal 407 to the switching circuit 109. The edge detection circuit 404 detects a falling edge or a rising edge of the head switching signal input from the input terminal 403. And
The decoding circuit 401 is reset by a synchronization control signal input from the control circuit 110 via the input terminal 404.

FIG. 9 shows the operation timing of the timing generation circuit 105. FIG. 9 shows the timing when the reset is performed at the falling edge of the head switching signal. The reference signal 1 is a reference signal for rotating head control generated by the analog signal recording / reproducing circuit 107, and the reference signal 2 is a reference signal for rotating head control generated by the timing generation circuit 105.

The reset is performed in the recording / reproducing mode of the analog signal, that is, when the rotary head is controlled by the reference signal 1 output from the analog signal recording / reproducing circuit. At this time, the head switching signal is synchronized with the reference signal 1. By resetting the decode circuit 401 so that the fall of the first head switching signal after the input of the synchronization control signal, that is, the fall of the head switch signal and the reference signal 2 at time A, the reference signal 2
And the recording / reproducing processing timing of the digital signal recording / reproducing circuit 104 can be synchronized with the rotational phase of the rotary head. Then, by switching from recording or reproduction of an analog signal to recording or reproduction of a digital signal at time point B, it is not necessary to resynchronize the rotary head at the time of the switching, and the recording or reproduction operation can be started immediately.

FIG. 10 shows the operation timing of the timing generation circuit 105 when the cycle of the reference signal is once per frame. Also in this case, synchronization can be performed in the same manner as in FIG.

Further, by keeping the number of rotations of the rotary head during analog recording and reproduction and the number of rotations of the rotary head during digital recording and reproduction the same, it is possible to further reduce the phase shift of the reference signal during switching. . When recording an analog video signal, it is necessary to make the rotation speed of the rotary head coincide with the frame period of the video signal. As described above, the same 30 / 1.001 Hz as the frame period is used. On the other hand, in the case of a digitally compressed video signal compressed by, for example, the MPEG method, there is no correlation between the compressed signal and the frame period, so that it is not necessary to synchronize the rotation speed of the rotary head with the frame period. So, for example,
It is conceivable to use 30 Hz, which is easier to generate than the reference clock. However, in this case, even if the synchronization is performed at the time point A in FIG. 9, the phases of the reference signal 1 and the reference signal 2 are shifted due to the difference in the number of rotations until the time point B at which the reference signal is switched. Would. The number of rotations of the rotary head during digital recording / reproducing is also 30 / 1.0 which is the same as that during analog recording / reproducing.
By using 01 Hz, the phase of the reference signal does not shift due to the difference in the number of rotations, and the phase relationship can be maintained even if the interval from the time point A for performing the synchronization to the time point B for performing the switching becomes long.

The synchronization may be performed a predetermined time before the switching is performed. For example, the digital signal recording / reproducing circuit 1
If it takes six tracks before the normal processing can be started after the synchronization, the synchronization may be performed six or more tracks before the point of switching. Also,
Synchronization may be performed at all times during recording and reproduction of analog signals, and the synchronization may be stopped before switching.

Although the reference signal 2 is synchronized based on the head switching signal in the embodiment of FIG. 8, the reference signal 1 may be used as the reference. In this case, the input terminal 40
3, the reference signal 1 generated by the analog signal recording / reproducing circuit 107 is input. Also, when switching from recording and reproduction of a digital signal to recording and reproduction of an analog signal, the same synchronization can be performed because the reference signal is generated by the oscillation circuit 116 during reproduction of the analog signal.
Further, the same synchronization can be performed when switching between recording and reproduction of a plurality of types of digital signals.

FIG. 11 shows the operation timing of the timing generation circuit 105 when the recording / reproduction processing timing of the digital signal recording / reproduction circuit 104 is shifted in the digital recording / reproduction mode. When the period of the reference signal is の of one rotation of the rotary head, tracks A and B
Can not be identified. Therefore, for example, when the rotary head rises from the stop state, for example, at the start of recording and reproduction, the rotation phase of the rotary head, that is, the phase of the head switching signal and the recording and reproduction processing timing of the digital signal recording and reproduction circuit 104 are reversed. There are cases. At this time,
Before starting the processing, the decoding circuit 401 is reset so that the fall of the head switching signal coincides with the processing timing of the track A at the time point A, so that the recording / reproducing processing timing is changed to the phase of the head switching signal. Can be synchronized.

The reset may be always performed at the start of recording or reproduction, or may be performed only when the relationship between the phase of the head switching signal and the recording and reproduction processing timing is confirmed and the timings are reversed.

[0028]

According to the present invention, when recording / reproducing by switching from recording / reproducing of an analog video signal to recording / reproducing of a digital compressed video signal, the phase of the reference signal of the rotary head control at the time of recording / reproducing the digital compressed video signal. By performing synchronization so that the recording / reproducing processing timing of the digital signal recording / reproducing circuit coincides with the rotating phase of the rotating head at the time of recording / reproducing an analog video signal, it is not necessary to resynchronize the rotating head at the time of switching, The recording or reproducing operation can be started instantly. Further, even when the rotational phase of the rotary head does not coincide with the recording / reproducing processing timing of the digital signal recording / reproducing circuit when the rotary head rises from the stop state, the recording / reproducing processing timing coincides with the rotational phase of the rotary head. In this way, there is no need to resynchronize the rotating head,
The recording or reproducing operation can be started instantly.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a rotary head recording / reproducing apparatus.

FIG. 2 is a diagram of a recording pattern on a tape.

FIG. 3 is a recording pattern diagram of one track.

FIG. 4 is a block diagram of each area.

FIG. 5 is a configuration diagram of ID information.

FIG. 6 is a configuration diagram of data of one track in a data recording area.

FIG. 7 is an operation timing chart of the rotary head control circuit.

FIG. 8 is a configuration diagram of a timing generation circuit.

FIG. 9 is an operation timing chart of the timing generation circuit.

FIG. 10 is another operation timing chart of the timing generation circuit.

FIG. 11 is another operation timing chart of the timing generation circuit.

[Explanation of symbols]

100: rotating head, 101: capstan, 102:
Switching circuit, 103: Switching circuit, 104: Digital signal recording / reproducing circuit, 105: Timing generation circuit, 106:
Oscillation circuit, 107 ... Analog signal recording / reproduction circuit, 108
... Rotary head control circuit, 109 ... Switching circuit, 110 ... Control circuit, 112 ... Magnetic tape, 116 ... Oscillation circuit, 40
1. Decode circuit, 402: Edge detection circuit.

Claims (9)

[Claims] A recording / reproducing circuit for recording / reproducing a signal; a rotary head for recording / reproducing a recording signal generated by the recording / reproducing circuit on a magnetic recording medium; A rotary head recording / reproducing apparatus comprising a rotary head control circuit for controlling, wherein a synchronizing means for synchronizing a timing of a recording / reproducing process of the recording / reproducing circuit with a rotation phase of the rotary head is provided. . 2. A rotary head recording / reproducing apparatus for switching between at least two different signals for recording / reproducing, wherein said recording / reproducing circuit comprises a first recording / reproducing circuit for recording or reproducing at least a first signal. And a second recording / reproducing circuit for performing recording / reproducing processing of a second signal, wherein the synchronizing means records / reproduces the first signal in synchronism with the rotating head in synchronization with the first recording / reproducing circuit. 2. The rotary head recording / reproducing apparatus according to claim 1, wherein the timing of the recording / reproducing process of the second recording / reproducing circuit is synchronized with the rotation phase of the rotary head when performing. 3. The rotary head control circuit, when recording or reproducing the first signal, controls the rotation of the rotary head with reference to a first reference signal generated by the first recording and reproducing circuit. And controlling the rotation of the rotary head with reference to a second reference signal generated by the second recording / reproducing circuit when recording or reproducing the second signal. 3. The rotary head recording / reproducing apparatus according to 2. 4. A rotary head recording / reproducing apparatus according to claim 2, wherein said first signal is an analog video signal, and said second signal is a digital compressed video signal. 5. The rotary head recording / reproducing apparatus according to claim 1, wherein said rotary head control circuit controls the rotation of said rotary head based on a reference signal generated by said recording / reproducing circuit. 6. The apparatus according to claim 5, wherein said synchronizing means synchronizes the timing of the recording / reproducing process of said recording / reproducing circuit with a signal generated by said rotary head control circuit and synchronized with a rotation phase of a rotary head. The recording / reproducing apparatus according to claim 1. 7. A rotary head recording / reproducing apparatus for switching between at least two different signals for recording / reproducing, a first recording / reproducing circuit for recording / reproducing a first signal, and a recording / reproducing circuit for a second signal. A second recording / reproducing circuit for performing a reproducing process; a rotary head for recording or reproducing a recording signal generated by the first or second recording / reproducing circuit on a magnetic recording medium; When performing the recording or reproduction of the above, the rotation of the rotary head is controlled based on the first reference signal generated by the first recording / reproduction circuit, and when performing the recording or reproduction of the second signal, In a rotary head recording / reproducing apparatus comprising a rotary head control circuit for controlling rotation of the rotary head based on a second reference signal generated by a second recording / reproducing circuit, the recording / reproducing of the first recording / reproducing circuit A rotating head recording / reproducing apparatus, wherein the period of the processing and the period of the first reference signal is the same as the period of the recording / reproducing process of the second recording / reproducing circuit and the period of the second reference signal. 8. The timing of the recording / reproducing process of the second recording / reproducing circuit and the timing of the second reference signal before switching from the recording / reproducing of the first signal to the recording / reproducing of the second signal. The rotating head recording / reproducing apparatus according to claim 7, wherein a phase is synchronized with a rotating phase of the rotating head. 9. The rotary head recording / reproducing apparatus according to claim 7, wherein said first signal is an analog video signal, and said second signal is a digital compressed video signal.