JP3000964B2 - Digital signal recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital signal recording / reproducing apparatus, and more particularly, to a use of a digital signal recording / reproducing apparatus by greatly shortening a recording time.

[0002]

2. Description of the Related Art Conventionally, as a digital signal recording / reproducing apparatus (digital VTR), for example, a D2 format VTR has been known. However, with such a conventional VTR, the playback time can be reduced by variable speed playback,
No mention is made of high-speed recording that reduces the recording time to a fraction.

[0003]

The above-described conventional digital VTR is characterized by high image quality and no dubbing deterioration, but no consideration has been given to shortening the dubbing time. For this reason, it takes two hours to record software of, for example, two hours, and there is a disadvantage that inconvenience occurs in usability.

An object of the present invention is to enable high-speed recording to be performed on a tape in the same format as standard-speed recording.
An object of the present invention is to provide a digital signal recording / reproducing apparatus capable of high-speed reproduction and to shorten the recording time, thereby expanding the use range of the digital VTR. For example, it can be used such that two-hour software is recorded in about 10 minutes and reproduced at a standard speed.

[0005]

The above object is achieved as follows. Transfer rate extracting means for extracting a transfer rate from a digital input signal which has been data-compressed and has been time-axis-compressed to 1 / n and transferred, and recording means for recording at the rate extracted by the transfer rate extracting means Is achieved by controlling

In particular, when an input signal is transferred at a speed exceeding twice the normal speed, the input signal sequence is divided into one or more sequences and recorded on a medium at the same time, so that the Recording can be performed under the condition that the increase in the signal processing speed and the signal recording speed is kept small.

In order to read a signal from a medium at a high speed for dubbing, one or more series of signal trains are simultaneously reproduced from the medium by using one or more series of reproducing means, and after demodulation processing, one series of signal sequences are converted to one signal. By performing the restoration, it is possible to perform the reproduction under the condition that the increase in the reproduction speed per one line is suppressed to a small value.

[0008]

FIG. 1 is an example of a block diagram of a digital signal recording / reproducing apparatus according to a first embodiment of the present invention, wherein 201 is a synchronization detection circuit, 202 is a synchronization frequency dividing circuit,
203 is a memory for temporarily storing and dividing information and 2
04 is a recording modulation circuit, 205 is a cylinder servo control circuit, 206 is a capstan servo (tape speed) control circuit, 207 is a reproduction reference signal generation circuit, 208 is a reproduction reference signal frequency dividing circuit, and 209 is a reproduction signal of a plurality of streams. A memory for temporarily storing and connecting, 210 is a demodulation circuit, 211
Is a cylinder, 212 is an m pair of recording heads, 213 is an m pair of reproducing heads, 214 is a capstan for controlling the tape speed, 215 is a recording medium, 216 is a sending reel, 217
Is a take-up reel.

During the recording operation, the cylinder servo circuit 20
5. The capstan servo circuit 206 includes the synchronization detection circuit 2
It operates under the control of the output from 01.

For a compressed video signal which is an input signal at the time of the recording operation of the present circuit, for example, if the signal is defined by the MPEG standard, a synchronizing signal indicating a cycle of a picture is added like a picture header. ing. Alternatively, in the digital television signal compressed on the time axis, a signal indicating a picture delimiter such as a vertical synchronization signal is inserted. The synchronization detection circuit 201 extracts the transfer speed of the input signal from these synchronization signals, and divides the input signal into a number of streams corresponding to the extracted speed. For example, n * m
When a compressed moving image signal transferred at double speed is input, the input signal is divided into m streams. here,
n does not need to be an integer and can take any value. That is, (n * m) does not need to be a multiple of m. However,
By setting m so that (n * m) is a multiple of m, it is possible to set a cylinder rotation speed, which will be described later, to an integral multiple of the normal speed, so that the control circuit can be easily stabilized. There is. An input signal transmitted at an arbitrary (n * m) speed is divided by defining m so that the recording speed per series n is a value that does not impose a load on a recording processing circuit, a recording head, a cylinder rotation speed, and the like. I do. In order to realize such division, an input signal is temporarily stored in the memory 203 at (n * m) times speed, and m-sequence signals are simultaneously extracted from this memory at n times speed. In order to generate a synchronizing signal for reading at the n-times speed, the (n * m) -times synchronizing signal is frequency-divided by m in the frequency dividing circuit 202. The input signals divided into the m series are respectively n
Predetermined recording modulation, for example, digital compression, error correction code addition, and recording modulation are performed at double speed, and are simultaneously recorded on a medium from m pairs of recording heads.

Here, the recording head moving speed controlled by the cylinder servo circuit and the medium feed speed controlled by the capstan servo circuit 206 have values other than 1 in the number of sequences and the transfer speed per sequence. Also, the recording position on the medium is controlled so as to be equivalent to the case where the recording position on the medium is one line and at 1 × speed. In order to make such a record,
The medium feeding speed is multiplied by (n * m) and the cylinder rotation speed is multiplied by n. For example, when input data transferred at 10 × speed is divided into two streams and each is recorded at 5 × speed, the medium feed speed is set to 10 times and the recording head moving speed is set to 5 times, so that the medium It is possible to record at 10 times normal speed, and it is possible to record input data transferred at 10 times speed in the same format as normal speed. At this time, since the ratio between the medium feeding speed and the head moving speed is different from the normal speed operation, the inclination of the recording track may deviate from the case of the normal speed. It is necessary to employ a movable head capable of moving the recording head on a cylinder.

Further, when it is necessary to adjust the frequency or amplitude of the signal after recording modulation according to the recording speed, it is also performed. As a result, it is possible to record in a format equivalent to the recording format obtained when recording at 1 × speed (normal speed).

On the other hand, during a reproducing operation, a plurality of series signals reproduced from the reproducing head 213 are subjected to a predetermined demodulation process in a demodulation circuit 210 and temporarily stored in a linking memory 209 to become one-series signals. Is read out. At this time,
The transfer speed of the finally obtained reproduction signal is determined by the output of the reference signal generation circuit 207. The cylinder servo circuit 205 and the capstan servo circuit 206 are controlled by the signal series connection memory 209 by the reference signal generation circuit 207. For example, in the case of reproducing at 2 × speed, the reproducing sequence is 2 sequences, the recording head moving speed controlled by the cylinder servo circuit is 1 × speed, and the medium feed speed controlled by the capstan servo circuit 206 is 2 × speed. . Under this condition, the reproduction speed per series is equal to the normal speed. As described above, according to the present embodiment, even in the case of high-speed reproduction, it is possible to suppress an increase in the reproduction speed of the reproduction head of each series to a low level, so that high-speed reproduction can be easily realized. . Further, since the reference signal generating circuit is provided separately from the input signal, the reproduction signal can be output at a predetermined transfer speed even when the transfer speed of the input signal is different from that of the reproduction signal. The speed of the reference signal generation circuit 207 may be any speed.

FIG. 2 is a diagram showing the timing of the input / output signals of this embodiment. Reference numeral 251 denotes a compressed image signal which is an input signal; 252, a sync signal of 251;
Is a plurality of series of signals read from the memory 203, 25
Reference numeral 4 denotes a synchronization signal divided by m, reference numeral 255 denotes a standard speed reproduction signal as an output signal, and reference numeral 256 denotes an outline of a reproduction synchronization signal. As shown in this figure, even when the input signal is input at (n * m) times speed, according to the present embodiment, the input transfer speed is detected from the synchronization signal, and the sequence is divided according to the speed. Recording operation, it is possible to perform recording at the same speed, and it is possible to perform recording under the condition that the increase in the recording speed per line is kept small, and it is possible to perform recording at the same speed as 1 × speed recording. It can be recorded on a medium in a format. Also, even with the medium recorded in this way, the reproduction speed is controlled by the output of the reference signal generation circuit 207, so that the medium can be reproduced at an arbitrary speed and the number of simultaneous reproduction sequences. It is also possible to play back at a different speed.

FIG. 3 is a table showing examples of combinations of the medium speed (tape speed), the recording / reproducing head speed (cylinder rotation speed), and the number of simultaneous recording / reproducing sequences (head number) under various conditions. In each case, at 1 × speed (normal speed), 60 screens are transferred per second.

In the example shown in the first embodiment, the cylinder rotates at a speed of 900 rpm at a normal speed, that is, at a speed of 15 rotations per second, and the winding angle is 180 degrees, that is, two tracks per rotation. This is the condition for recording and playback. Under these conditions, 30 tracks are recorded / reproduced per second,
The number of tracks required for recording and reproducing the screen is 本. Under these conditions, in order to perform recording at a 10-times speed with one series of heads, it is necessary to increase the number of cylinder rotations by a factor of 10 to 9000. According to the present invention, it is possible to arbitrarily select the recording speed, the number of recording sequences, the reproduction speed, and the number of reproduction sequences. Therefore, as shown in FIG. Playback, 1x speed recording 1
Various combinations of recording / reproducing speeds such as 0-times speed reproduction are possible.

In the same figure, the example shown in the second embodiment is an example of one-time recording / reproduction at a cylinder rotation speed of 900 rpm in the normal speed recording / reproduction, and the example shown in the third embodiment is the normal speed recording / reproduction. This is an example of recording / reproducing the cylinder rotation at 1800 rpm in one series. As in the first embodiment, it is possible to realize various combinations of recording / reproduction speeds by controlling the cylinder rotation.

In the same figure, the example shown in the fourth embodiment is an example of a cylinder rotation speed of 900 rpm and two-sequence recording / reproduction in normal speed recording / reproduction, and the cylinder rotation speed is controlled similarly to the first embodiment. Thus, it is possible to realize various combinations of recording and reproducing speeds.

In the figure, the example shown in the fifth embodiment is an example of 1800 rpm cylinder rotation at normal speed recording / reproduction, and one-line recording / reproduction. By using a series, 10-times speed recording is realized under the condition that the cylinder rotation speed is suppressed to 5 times. Also, 1
Also in the 0 × speed reproduction, the 10 × speed reproduction is realized under the condition that the cylinder rotation speed is suppressed to 5 times by setting the number of reproduction sequences to two. As described above, according to the present invention, the medium speed (tape speed), the recording / reproducing head speed (cylinder rotation speed), and the number of simultaneous recording / reproducing sequences (head number) are arbitrarily set according to the recording speed or the reproducing speed. Since it can be determined, it is possible to realize 10-times recording / reproducing even under the condition that the cylinder rotation speed is suppressed to about 5 times.

[0020]

As described above, according to the present invention,
A digital digital recording / reproducing apparatus capable of high-speed recording and high-speed reproduction can be realized, and the recording time, the data transfer time, and the like can be reduced. Also, while keeping the increase in medium speed and recording / reproducing head speed small,
Higher speed recording and reproduction can be realized.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a digital recording / reproducing apparatus according to the present invention.
It is a block diagram showing an embodiment.

FIG. 2 is an example of input / output signal timing of the digital recording / reproducing apparatus of the first embodiment.

FIG. 3 is an example of recording / reproducing condition combinations of the digital recording / reproducing apparatus of the first embodiment.

[Explanation of symbols]

201: synchronous detection circuit 202: synchronous frequency dividing circuit 203: memory for temporarily storing and dividing information 204: recording modulation circuit 205: cylinder servo control circuit 206: capstan servo (tape speed) Control circuit 207: reproduction reference signal generation circuit 208: reproduction reference signal frequency dividing circuit 209: memory for temporarily storing and connecting a plurality of series of reproduction signals 210: demodulation circuit 211: cylinder 212: recording Head 213: Playback head 214: Capstan 215 for controlling the tape speed 215: Recording medium 216: Sending reel 217: Take-up reel

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Keizo Nishimura 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Home Appliances Research Laboratory, Hitachi, Ltd. (72) Inventor Yuzumi Watani 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Inside Hitachi, Ltd., Home Appliances Research Laboratories (72) Inventor Akira Shibata 292, Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside Hitachi, Ltd. Home Appliances Research Laboratories (56) References JP-A-2-176822 (JP, A) JP-A-3-165371 (JP, A) JP-A-64-55784 (JP, A) JP-A-1-128859 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5 / 91-5/956 H04N 5/782-5/783

Claims (3)

(57) [Claims] 1. A digital signal recording / reproducing apparatus for recording / reproducing a digital signal which is continuous in time, a transfer rate extracting means for extracting a transfer rate of an input digital signal, and an extraction result of the transfer rate extracting means being reflected. Signal sequence dividing means for dividing an input signal into one or more sequences, recording means for simultaneously recording one or more signal sequences on a medium, extraction results of the transfer rate extracting means, and signal sequence dividing means 1. A digital signal recording / reproducing apparatus comprising a recording speed control means for controlling a recording speed by reflecting the number of divisions. 2. The recording speed control means according to claim 1, wherein said recording speed control means operates to record the input digital signals having different transfer rates so that the recording format on the medium is the same. Digital signal recording / reproducing device. 3. A digital signal recording / reproducing apparatus for recording / reproducing a digital signal continuous in time, wherein one
A reproducing means for reproducing a signal sequence equal to or more than a series from a medium, a coupling means for coupling the output of the reproducing means, and a reproduction signal at a predetermined transfer speed regardless of the number of signal sequences to be reproduced simultaneously or the transfer speed of the input digital signal. A reproduction speed control means for controlling a reproduction speed so as to output a digital signal.