JPH06189250A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable high density recording by executing frame synchronization in multiple segment recording without requiring an exclusive control track at the time of reproducing. CONSTITUTION:Recording means 2-8 record segment information indicating the segment number of the recording track in the recording track together with an input signal. A system synchronizing circuit 18 generates a frame change-over pulse for synchronizing a servo circuit 19 at the time of recording. Reproducing means 10-16 generate the frame change-over pulse for synchronizing the servo circuit 19 at the time of reproducing by the system synchronizing circuit 18, reading the segment number by executing servo, reading the segment number which indicates the track of No.1 segment and starts the signal processing frame pulse by a frame pulse generating means 20a from the point of time. The signal processing frame pulse is adopted as a reference frame pulse so as to execute frame synchronization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a VTR (Video Tape Recorder) for performing multi-segment recording, and more specifically, it is effective in frame synchronization when external synchronization is not required during reproduction. The present invention relates to a magnetic recording / reproducing device capable of achieving

[0002]

2. Description of the Related Art In a multi-segment recording type VTR, 1
A video signal for a frame is divided into a plurality of tracks and recorded on a magnetic tape. In the case of a VTR of such a recording system, at the time of recording, if the segment written first after the frame is switched is the No. 1 segment,
Even during playback, after switching frames, No. 1
If the segment is not read first, the data of one frame before or one frame after is mixed into one frame of the reproduced image, and normal reproduction cannot be performed. Therefore, in the above multi-segment recording method, frame synchronization is always required to reproduce from the track of No. 1 segment with respect to frame switching.

Conventionally, as a general frame synchronization system,
There is a CTL signal system in the UNIHI-VTR. The CTL signal system is a system in which a control track is provided in a portion other than a portion where a video signal or the like on a tape pattern is recorded, and at the time of reproduction, a CTL signal written on the control track is detected to establish frame synchronization. Is.

FIG. 5 is a block diagram of a magnetic recording / reproducing apparatus for explaining another conventional frame synchronization method.
Is an input terminal, 32 is an A / D converter, 33 is a compression encoder, 34 is an ECC (Error Correcting Code) encoder, 35 is a modulation circuit, 36 is a recording equalizer, 37 is a recording amplifier, 38 is a magnetic head, 39
Is a magnetic tape, 40 is a reproducing head, 41 is a reproducing amplifier,
42 is a reproduction equalizer, 43 is a demodulation circuit, and 44 is an ECC.
Decoder, 45 is compression decoder, 46 is D / A converter, 47 is output terminal, 48 is system synchronizing circuit, 49 is servo circuit, 50 is frame synchronizing circuit, 50a is frame pulse generating circuit, 50b is segment information detecting circuit,
Reference numeral 50c is a frame pulse selection circuit.

FIGS. 6 (a) to 6 (h) are diagrams showing signals of respective portions in FIG. 5, FIG. 6 (a) being a temporary frame pulse, FIG. 6 (b) being a head switching pulse, and FIG. 6 (c) being reproduction. Phase signal, figure (d) is a reference frame pulse, figure (e) is a reproduction phase signal, figure (f) is a reference frame pulse, figure (g) is a reproduction phase signal, and figure (h) is a reference frame pulse. Each is shown. As shown in FIGS. 5 and 6, based on the segment information detected by the segment information detecting means, N
o. In order to reproduce from the track of 1 segment, in other words, prepare a plurality of reference frame pulses with different segment phases so that the frame pulse rises on the track of No. 1 segment, and select from among them N frames.
A method has been proposed in which one is selected such that the frame pulse rises in the track of one segment.

[0006]

As described above, in the conventional CTL signal system, a frame synchronization signal (CTL signal) is written by providing another track in addition to the track for recording a video signal and the like. , A dedicated fixed head is required, and there are multiple mechanisms. Further, since the recording tape is exclusively used for recording on the magnetic tape, it is disadvantageous when performing high density recording. Further, in the frame synchronization method proposed in addition to the conventional CTL signal system, since the track of No. 1 segment is reproduced based on the segment information detected by the segment information detecting means, in other words, No. Prepare a plurality of reference frame pulses with different segment phases so that the frame pulse rises on the track of the .1 segment, and select one such that the frame pulse rises on the track of the No. 1 segment. In the selection method, a means for generating a plurality of reference frame pulses having different phases and a means for selecting a plurality of reference frame pulses having different phases are required, and the circuit is complicated and large in scale.

The present invention has been made in view of the above circumstances, and when reproduction does not require external synchronization, frame synchronization in multi-segment recording is achieved without requiring a dedicated control track. Due to
It is an object of the present invention to enable high-density recording, reduce the load on the servo circuit, and provide a magnetic recording / reproducing apparatus that is capable of downsizing a complicated and large-scale circuit.

[0008]

In order to achieve the above object, the present invention provides (1) a system synchronizing circuit for generating a frame switching pulse synchronized with an input signal at the time of recording, and a plurality of system synchronizing circuits based on the frame switching pulse. In a magnetic recording / reproducing apparatus, the recording signal is divided into a plurality of tracks on the magnetic tape, and the reproducing means reproduces the signal recorded on the magnetic tape. The recording means records segment information indicating a segment number of a recording track on the recording track together with the input signal, and the system synchronizing circuit generates a frame switching pulse for synchronizing a servo circuit at the time of recording, and the reproducing means. Reproduces the signal recorded on the recording track, and the system synchronization circuit synchronizes the servo circuit during reproduction. It generates a frame switching pulse to,
A segment information detection circuit for reading a segment number indicating a track of the No. 1 segment by applying a servo, and a frame pulse generation circuit for starting a signal processing frame pulse from the time of the track of the No. 1 segment, Frame synchronization using the frame pulse for signal processing as a reference frame pulse, and further,
(2) If the signal becomes discontinuous, read the segment number again in order to synchronize with the reproduced signal and read N
o. The feature is that the frame pulse for signal processing is started from the time when the segment number indicating the track of 1 segment is read.

[0009]

The magnetic recording / reproducing apparatus is of a so-called multi-segment recording system in which an input signal for one frame consisting of a plurality of segments is divided and recorded on a plurality of tracks on a magnetic tape based on a frame switching pulse. At this time, the recording means records the segment information indicating the segment number of the recording track on the recording track together with the input signal. At the time of reproduction, the segment number is read and the frame pulse for signal processing is started from the time when the segment number indicating the track of the No. 1 segment is read. This signal processing frame pulse is used as a reference for signal processing by the reproducing means, and frame synchronization is established based on the signal processing frame switching pulse. Therefore, it is possible to achieve frame synchronization in multi-segment recording without requiring a dedicated control track. Further, in the above case, the signal processing frame switching pulse and the servo circuit frame switching pulse are separate, and the servo circuit only performs tracking control and does not need to perform frame synchronization, which reduces the load on the servo circuit. To be done. When the signal becomes discontinuous, the segment number is read again in order to synchronize with the reproduction signal, and the frame pulse for signal processing is started at the time when the segment number indicating the track of the No. 1 segment is read.

[0010]

Embodiments will be described below with reference to the drawings. FIG. 1 is a block diagram of a digital VTR for explaining an embodiment of a magnetic recording / reproducing apparatus according to the present invention. It should be noted that in the VTR, an audio signal and other additional information are recorded in addition to the video signal, but for the sake of convenience of description, the figure shows a configuration in which only the video signal is processed. Also,
In the embodiment of the present invention, two heads having different azimuth angles are arranged so as to face a rotary drum, rotated at 5400 rpm, and one frame of data is composed of 6 segments.
FIG. 3 shows an example of division recording on a book track.
An example of the track pattern written on the magnetic tape 9 is shown in FIG. Note that S1 to S6 recorded in FIG.
The segment number of the track is shown. 1 in the figure
Is an input terminal, 2 is an A / D converter, 3 is a compression encoder, 4 is an ECC encoder, 5 is a modulation circuit, 6 is a recording equalizer, 7 is a recording amplifier, 8 is a magnetic head, 9 is a magnetic tape, 10 is a reproducing head. , 11 is a reproduction amplifier, 12 is a reproduction equalizer, 13 is a demodulation circuit, 14 is an ECC decoder, 15 is a compression decoder, 16 is a D / A converter, 1
Reference numeral 7 is an output terminal, 18 is a system synchronization circuit, 19 is a servo circuit, 20 is a frame synchronization circuit, 20a is a frame pulse generation circuit, and 20b is a segment information detection circuit.

A system synchronizing circuit 18 for generating a frame switching pulse synchronized with an input signal at the time of recording and an input signal for one frame consisting of a plurality of segments based on the frame switching pulse are divided into a plurality of tracks on a magnetic tape 9. The magnetic recording / reproducing apparatus includes recording means 2 to 8 for recording and reproducing means 10 to 16 for reproducing the signal recorded on the magnetic tape 9.

That is, the recording means 2 to 8 store the segment information indicating the segment number of the recording track,
It is recorded on the recording track together with the input signal. Then, the system synchronization circuit 18 generates a frame switching pulse for synchronizing the servo circuit 19 during recording. Further, the reproduction means 10 to 16 generate a frame switching pulse for synchronizing the servo circuit 19 at the time of reproduction by the system synchronization circuit 18, read the segment number by applying servo, and read the track of No. 1 segment. The segment number shown is read, and the frame pulse generation means 20a starts a signal processing frame pulse from that point. Frame synchronization is achieved by using the signal processing frame pulse as a reference frame pulse.

As shown in FIG. 1, the VTR constitutes a reproducing system (reproducing means) for reproducing the recording signal recorded on the magnetic tape 9. Two reproducing heads A and B having different azimuths, reproducing amplifier 11, reproducing equalizer 1
2. Demodulation circuit 13, E as segment information detecting means
CC decoder 14, compression decoder 15, D / A converter 16, and frame synchronization circuit 20 as reference frame switching pulse generation means (segment detection circuit 20b as No. 1 segment detection means and reference frame switching pulse for signal processing) And a frame generation circuit 20a as a generation means).

The reproducing operation of the VTR will be described below. The output from the reproducing head 10 tracing the magnetic tape 9 is the reproducing amplifier 11 and the reproducing equalizer 12.
Is input to the demodulation circuit 13 via the, and the synchronization code (see FIG. 4) is detected by the demodulation circuit 13 and demodulated. The demodulated signal is error-corrected by the ECC decoder 14 based on the error-correction parity (see FIG. 4), and then compressed data is restored by the compression decoder 15.
After that, a reproduction video signal converted into an analog signal by the D / A converter 16 is formed, and the reproduction video signal is output from the output terminal 17 to a television monitor or the like.

FIGS. 2A to 2E are timing charts during reproduction in FIG. 1. FIG. 2A is a frame pulse of the servo circuit, FIG. 2B is a head switching pulse, and FIG. 2C is reproduction. Output, FIG. 7D is a segment discrimination signal, and FIG. 8E is a reference frame pulse for signal processing. At the time of reproduction, since there is no input signal serving as a frame pulse reference, a frame switching pulse is generated in the system synchronizing circuit 18 as a frame switching pulse generating means.
This frame switching pulse is output to the servo circuit 19. The servo circuit 19 which has received the frame switching pulse (Fig. (A)) causes the reproducing head switching pulse (Fig. (B) which rises to the same position as the rising of the frame switching pulse (Fig. (A)) as in recording. )) Is generated, and tracking is adjusted so that the reproducing head 10 surely traces the recording track on the magnetic tape 9.

However, the servo circuit 19 always performs S1 with respect to the rising edge of the frame switching pulse (FIG. 7A).
You don't need to control to play from the track. Which track is reproduced first with respect to the frame switching pulse is detected from the segment information in the ID code (see FIG. 4) supplied from the demodulation circuit 13. With the segment information, even if some errors occur in the video signal, the audio signal, and the additional information in one track, the segment number of the track can be accurately detected by the majority theory or the like. The detected segment number is input to the segment information detection circuit 20b that constitutes the frame synchronization circuit 20, and in the segment information detection circuit 20b, No. 1 is input.
By detecting the segment, the segment discrimination signal (Fig. 2
(D)) is input to the frame generation circuit 20a that constitutes the frame synchronization circuit 20, and the reference frame switching pulse for signal processing is generated from that point so that the frame switching pulse rises in the No. 1 segment track. . The frame switching pulse is supplied as a reference frame switching pulse for signal processing to the reproduction signal processing system after the demodulation circuit 13 such as the ECC decoder 14 and the compression decoder 15.

As described above, when external synchronization is not required during reproduction, the reference frame switching pulse for signal processing is set to rise on the No. 1 segment track so that a dedicated control track is set. Frame synchronization in multi-segment recording can be quickly achieved without the need. Also, the servo circuit 19
It suffices to rotate the rotary drum in synchronism with the frame switching pulse a supplied from the system synchronization circuit 18 and adjust the tracking of the rotary head (playback head 10). The burden is reduced. Further, the frame generation circuit 20a does not need to generate a plurality of different reference frame switching pulses, and the rising of the reference frame switching pulse for signal processing is generated in the track of the No. 1 segment among the plurality of different reference frame switching pulses. The frame pulse selection circuit 50c for selecting to be omitted becomes unnecessary.

Further, although the above description was for normal reproduction, because of the non-recorded portion in the middle of the magnetic tape,
The signal becomes discontinuous and a phase shift occurs between the signal processing frame switching pulse and the reproduction signal. Therefore, when the phase shift between the signal processing frame switching pulse and the reproduction signal is detected, and if it exceeds a certain range, the segment number is read again in order to synchronize with the reproduction signal and N
o. A frame pulse for signal processing is started at the time when the segment number indicating the track of one segment is read. In the embodiment of the present invention, one frame of data is composed of 6 segments and dividedly recorded on six tracks. However, the present invention is not limited to this. For example, one frame of data may be recorded. 8 segments
It may be recorded separately on a book track.

FIG. 4 is a diagram showing an example of a track format of a digital VTR. That is, in one track, first a preamble, then a video signal divided into blocks, a first postamble, a first guard that serves as a boundary between a video signal and an audio signal, and a second The preamble, the block-divided audio signal, the second postamble, the second guard that is the boundary between the audio signal and the additional information, the third preamble, the block-divided additional information, and the third postamble are sequentially recorded. It has become so. For example, one of the above video signals divided into blocks
In addition to video data, a sync code for block start determination, an ID (Identification) code having recording track information and segment information described later, and an error correction parity are added to the block. In addition, in the same way as described above, the sync code, the ID code, and the error correction parity are added to each block of the audio signal and the additional information, which are divided into blocks.

[0020]

As is apparent from the above description, the present invention has the following effects. That is, a system synchronization circuit for generating a frame switching pulse synchronized with an input signal at the time of recording, and an input signal for one frame consisting of a plurality of segments based on the frame switching pulse are recorded separately on a plurality of tracks on a magnetic tape. Means and
A magnetic recording / reproducing apparatus having reproducing means for reproducing a signal recorded on the magnetic tape, comprising the following means. That is, the recording means records the segment information indicating the segment number of the recording track on the recording track together with the input signal. Then, the system synchronization circuit generates a frame switching pulse for synchronizing the servo circuit during recording. In addition, the reproducing means,
The system synchronization circuit generates a frame switching pulse for synchronizing the servo circuit at the time of reproduction, reads the segment number by applying servo, reads the segment number indicating the track of the No. 1 segment, and generates the frame pulse from that point. The signal processing frame pulse is started by the means. This signal processing frame pulse is used as a reference frame pulse for frame synchronization. Therefore, if external synchronization is not required during playback, you do not need a dedicated control track,
Since it is possible to achieve frame synchronization in multi-segment recording, it is advantageous when performing high-density recording. Furthermore, the servo circuit does not need to establish frame synchronization by performing tracking control in synchronization with the frame switching pulse from the system synchronization circuit, and thus the load on the servo circuit can be reduced. Further, since it is unnecessary to generate and select many kinds of frame switching pulses having different phases, there is an effect that a complicated and large-scale circuit becomes small.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining an embodiment of a digital VTR which is a magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a diagram showing a timing chart of each signal during reproduction in the digital VTR of the present invention.

FIG. 3 is a diagram showing an example of a tape pattern of a digital VTR of the present invention.

FIG. 4 is a diagram showing an example of a track format of a digital VTR of the present invention.

FIG. 5 is a block diagram of a conventional digital VTR.

FIG. 6 is a diagram showing a timing chart of each signal during reproduction in a conventional digital VTR.

[Explanation of symbols]

1 ... Input terminal, 2 ... A / D converter, 3 ... Compression encoder, 4 ... ECC (Error Correcting Code) encoder, 5 ... Modulation circuit, 6 ... Recording equalizer, 7 ... Recording amplifier, 8 ... Magnetic Head, 9 ... Magnetic tape, 10 ... Reproducing head, 11 ... Reproducing amplifier, 12 ... Reproducing equalizer, 13 ... Demodulation circuit, 14 ... ECC decoder,
15 ... compression decoder, 16 ... D / A converter, 17 ...
Output terminal, 18 ... System synchronization circuit, 19 ... Servo circuit, 20 ... Frame synchronization circuit, 20a ... Frame pulse generation circuit, 20b ... Segment information detection circuit.

Claims (2)

[Claims] 1. A system synchronizing circuit for generating a frame switching pulse synchronized with an input signal at the time of recording, and an input signal for one frame consisting of a plurality of segments based on the frame switching pulse, to a plurality of tracks on a magnetic tape. In a magnetic recording / reproducing apparatus provided with recording means for division recording and reproducing means for reproducing a signal recorded on the magnetic tape, the recording means stores segment information indicating a segment number of a recording track in the input signal. Along with recording on the recording track, the system synchronizing circuit generates a frame switching pulse for synchronizing the servo circuit at the time of recording, and the reproducing means reproduces the signal recorded on the recording track and reproduces by the system synchronizing circuit. Occasionally, the frame switching pulse that synchronizes the servo circuit is generated and the servo is turned on. A segment information detection circuit for reading the segment number indicating the track of the .1 segment and a frame pulse generation circuit for starting the frame pulse for the signal processing from the time of the track of the No. 1 segment are provided. A magnetic recording / reproducing apparatus characterized by taking frame synchronization as a reference frame pulse. 2. When the signal becomes discontinuous, the segment number is read again in order to synchronize with the reproduced signal, and the frame for signal processing is started from the point when the segment number indicating the track of No. 1 segment is read. The magnetic recording / reproducing apparatus according to claim 1, wherein a pulse is started.