JPH08227546A - Recording and reproducing device for encoded data sequence - Google Patents

Abstract

PURPOSE: To realize efficient recording and reproducing by changing a tape feed speed according to the bit rate of input encoded data sequence and changing the number of channels used for recording and reproducing. CONSTITUTION: The prescribed processing necessary for recording on a magnetic tape is executed in recording processing circuits 3, 4 and a magnetic tape 8 is subjected to recording via heads 6 and 7 for recording. A tape feed control circuit 5 feeds the tape in such a manner that the tape feed speed is made two-fold the tape feed speed at the time when the bit rate is N (Mbps). Four pieces of tracks of the same width as the width at the time when recording is executed in one channel are formed by the heads 6a, 6b, 7a and 7b by one turn of a cylinder 15. The data are outputted by integrating the dat to one channel of the encoded data sequence with an output I/F circuit 13 at the time of reproducing. As a result, the recording and reproducing of the encoded data sequence of the bit rate twice higher than in the case the first channel is used are made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recording / reproducing an encoded data string whose bit rate changes.

[0002]

2. Description of the Related Art Currently, multi-channel satellite broadcasting services are provided in the United States. By using digital compression technology, video signals and audio signals are significantly compressed to realize multi-channels. The bit rate is changed according to the content of the program to be broadcast, and a low bit rate (for example, 3 Mbps.) Is allocated to movies and the like, and a high bit rate (for example, 6 Mbps) is allocated to live broadcasting and the like. Also in Japan and Europe, similar services are scheduled to start using satellites, terrestrial waves, and cables.

In other words, the latest digital compression technology is used to reduce the communication cost per channel to realize multi-channel.

[0004]

When the service as described above is started, the current consumer VTR (for example, VH) is used.
S, S-VHS, 8 mm, etc. ), The received signal is decoded and the analog video signal is analog-recorded. Therefore, the case where the broadcast of 3 Mbps is received and the case of 6 Mbps are received.
It is not possible to change the recording time depending on the bit rate of the input coded data string when the s broadcast is being received. Also, even though a large number of programs are being broadcast at the same time, two types of programs can be recorded on one VTR.
Can't record at the same time.

This is because even though a video signal or an audio signal is compressed and transmitted at a reduced data rate, the transmitted information is decoded into an analog video signal or an audio signal and then input to a VTR. This is because

The present invention solves the above problems and realizes a VTR which enables a long recording time when a program having a low bit rate is input and which can simultaneously record a plurality of programs. become able to.

[0007]

In order to solve the above problems, a recording / reproducing apparatus for encoded data strings according to the present invention comprises a plurality of recording processing circuits and reproduction processing circuits, and has a bit rate of an input encoded data string. The tape feed speed is changed according to the number of channels and the number of channels used for recording and reproduction is changed.

[0008]

According to the present invention, by adopting the above configuration, when the bit rate of the input encoded data string is low, 1
When the bit rate of the input encoded data string is high by using the channel recording / reproducing processing circuit, the tape feed is changed and the recording / reproducing processing circuit of a plurality of channels is used for recording / reproducing.

That is, efficient recording and reproduction is realized by changing the tape consumption amount according to the bit rate of the input code data.

It is also possible to record / reproduce a plurality of types of encoded data having a low bit rate by using a recording / reproducing processing circuit of a plurality of channels.

Further, since recording / reproducing is performed in the state of digital signals, it is possible to record / reproduce after decoding into analog signals.
It also has an advantage that image quality is hardly deteriorated as compared with the current VTR to be reproduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a coded data string recording / reproducing apparatus according to the present invention will be described below with reference to FIGS. 1, 2 and 3.

FIG. 1 is a block diagram showing a structure of a recording / reproducing apparatus for an encoded data string of the present invention, FIG. 2 is a view showing a structure of a cylinder, and FIG. 3 is a view showing a pattern of recording tracks.

In FIG. 1, 1 is an input terminal for inputting an encoded data string, 2 is an input for detecting a bit rate from the input encoded data, and dividing the input signal into two channels according to the bit rate of the input signal. I / F circuits, 3 and 4
Are recording processing circuits 1 and 2 and 5 for converting the encoded data string into signals suitable for recording on a magnetic tape, and a tape feed control circuit 6 for changing the magnetic tape feeding speed according to the bit rate of the input encoded data string. And 7 are recording heads, 8
Is a magnetic tape, 9 and 10 are reproducing heads, 11 and 12 are reproduction processing circuits for performing predetermined signal processing on the reproduced signals, and 13 is a circuit for returning the reproduced signals to the same encoded data sequence as at the time of recording. The output I / F circuit, 14 is an output terminal.

The operation of the recording / reproducing apparatus configured as described above will be described with reference to the drawings. In FIG.
The bit rate of an input signal that can be recorded / reproduced using the first channel, that is, the recording processing circuit 1 of 3, the recording head of 6 and the reproducing head of 9 and the reproducing processing circuit of 11, is N (Mbps). In addition, the bit rate of the input signal recordable and reproducible using the second channel, that is, the recording processing circuit 2 of 4, the recording head of 7 and the reproducing head of 10 and the reproducing processing circuit of 12, is the same as that of the first channel. The same N1 (Mbps) is set. Furthermore, the bit rate of the encoded data string input to the recording / reproducing apparatus is N (M
Bps) or 2 * N (Mbps). The structure of the head used for actual recording and reproduction is shown in FIG. In FIG. 2, 15 is a cylinder in which the head is mounted, 6a and 6b correspond to the head 6 for the first recording channel in FIG. 1, and 7a and 7b are heads 7 for the second recording channel in FIG. Equivalent to.

When an encoded data string having a bit rate of N (Mbps) is input, the input I / F circuit 2 detects that the bit rate is N, and the recording processing circuit 1 of 3 is used.
The encoded data string is output only to (the recording processing circuit 2 of 4
It is the same even if it outputs only to. ) 3 recording processing circuit 1
Then, after the predetermined processing necessary for recording on the magnetic tape such as ECC encoding, addition of sync data / ID data, modulation, recording equalization and recording amplification is performed on the input encoded data string, the recording is performed. Data is recorded on the magnetic tape 8 via the recording head 6. At this time, the recording processing circuit 2 of 4 does not operate, and the recording head 7 does not perform recording. The recording track pattern on the magnetic tape at this time is shown in FIG. FIG. 3B shows the pattern when the cylinder 15 makes one rotation, and the recording head 6
Two recording tracks are formed by a and 6b. During reproduction, a signal reproduced by the reproducing head 9 is subjected to predetermined processing such as detection and protection of sync and ID data and ECC decoding by the reproduction processing circuit 11. The output I / F circuit 13 returns the reproduced data to a coded data string conforming to the standard and outputs it.

Next, the bit rate is 2 * N (Mbps)
Consider the case where the encoded data string of is input. Input I /
The F circuit 2 detects that the bit rate is 2 * N (Mbps), divides the input encoded data string into 2 channels, and outputs the data string to the recording processing circuit 1 of 3 and the recording processing circuit 2 of 4. To do. The recording processing circuits 3 and 4 perform the predetermined processing required for recording on the magnetic tape described above,
Recording is performed on the magnetic tape 8 via the recording heads 6 and 7. Further, since the bit rate is 2 * N (Mbps), the tape feeding control circuit 5 feeds the tape so that the tape feeding speed is twice as high as that when the bit rate is N (Mbps). The recording track pattern on the magnetic tape at this time is the heads 6a, 6b, 7a when the cylinder 15 makes one rotation as shown in FIG.
And 7b, four tracks having the same width as when recording on one channel are formed. At the time of reproduction, the same processing as the reproduction processing of only the first channel described above is performed for each channel, and the output I / F circuit 13 integrates the encoded data string of one channel and outputs it. By adopting such a configuration, it is possible to record / reproduce an encoded data string having a bit rate twice as high as that in the case of using the above-mentioned first channel.

In the above description, when recording and reproducing using only the first channel, the bit rate of the input encoded data string is N (Mbps), which is the same as the recordable bit rate. It is obvious that the same thing can be said even if an encoded data string of (Mbps) or less is input.

In the above description, the bit rate of the input encoded data string is doubled.
Obviously, the same thing can be said by increasing the number of recording / reproducing channels even in the case of more than double and from 1 to 2 times.

Although the recording head and the reproducing head are described separately, it is obvious that the same thing can be said for both recording and reproducing.

Further, in the above description, the magnetic tape is used as the recording medium, but it is obvious that the same applies to a medium such as a disk or a semiconductor memory.

The second embodiment of the present invention will be described with reference to FIG. In FIG. 4, 16 is an input terminal to which an analog video signal is input, 17 is an analog recording processing circuit for performing the processing necessary for analog recording of the analog video signal on a magnetic tape, and 18 is a recording for analog video signal recording. A head 19 is a reproducing head for reproducing an analog video signal, a reference numeral 20 is an analog reproduction processing circuit for reproducing an analog video signal from a reproduced signal, and a reference numeral 21 is an output terminal for the analog video signal. Further, 23 is a first switch for prohibiting recording of an analog video signal, 24 is a second switch for prohibiting recording of an encoded data string, and 22 is a control of the first and second switches according to an input signal. It is an input switching circuit.

The block in the dotted line in the lower half of FIG. 4 is the recording / reproducing processing unit for the encoded data string, and since it overlaps with the description in FIG. 1 described above, the description thereof is omitted here.

The operation of the recording / reproducing apparatus configured as described above will be described with reference to the drawings. When the analog video signal is input, the output from the input switching circuit 22 puts the first switch 23 in the connected state, and the analog video signal can be recorded. The analog recording processing circuit 17 performs processing necessary for analog recording on the magnetic tape, such as emphasis, clipping, equalizing, FM modulation and recording amplification, and supplies a recording signal to the recording head 18. When analog recording is performed, the cylinder is driven at a predetermined rotation speed. For example, in the case of a VHS type VTR (when the cylinder diameter is 62 mm), the cylinder rotation speed is 1800 rpm. When the encoded data string is input, the second switch circuit 24 is connected by the output from the input switching circuit 22, and the encoded data string is digitally recorded. When digital recording is performed, the cylinder rotation speed is the same as when analog recording is performed (for example, VH).
1800 rpm for S type VTR. ). When the recording / reproducing function of the encoded data string is added to the current VTR that records / reproduces analog video signals, the I / F condition of the tape and head changes when the cylinder rotation speed changes, and It is difficult to keep the head area constant.

That is, by making the cylinder rotation speed the same as the current analog recording VTR, it is possible to construct a VTR capable of digital recording and analog recording without changing the specifications.

Further, when both the analog video signal and the encoded data sequence are input, the input switching circuit gives priority to the recording of the analog video signal to insert a magnetic tape incapable of digital recording in the VTR. Since it is always recorded in analog, it is possible to prevent mistakes such as unrecorded data.

Further, in the above description, the head for recording the analog video signal and the head for recording the encoded data string are separate, but the analog signal and the encoded data string are switched immediately before the recording head or the recording amplifier circuit. With such a configuration, there is an advantage that the head or the recording / amplifying circuit can be shared.

In the above description, the recording / reproducing of the encoded data string is one channel, but it is obvious that the same thing can be said when there are a plurality of channels.

A third embodiment of the present invention will be described with reference to FIGS. In FIG. 5, what is different from the encoded data string recording / reproducing apparatus according to claim 1 is that
That is, only one channel is used for recording and reproduction, and 27 cylinder drive circuits are provided. In this embodiment, the recording channel is always one channel in response to the change in the bit rate of the input encoded data string, and the cylinder drive circuit 27 changes the rotation speed of the cylinder according to the bit rate. That is, as shown in FIG. 6, only the recording / reproducing heads 6a and 6b are provided, and the bit rate of the input encoded data string is N (Mb
When the bit rate is 2 × N (Mbps), the cylinder rotates at the first rotation speed M (rpm), and when the bit rate is 2 × N (Mbps), the cylinder rotates at the second rotation speed 2 × M (rpm). Further, when the bit rate is doubled, the tape feeding speed is doubled. As shown in FIG. 3, the recording track pattern in the recording / reproducing apparatus configured as described above has a bit rate of 2 in FIG. 3B when the bit rate of the input encoded data string is N (Mbps). When xN (Mbps), it becomes as shown in FIG. 3A (FIGS. 3A and 3B are recording track patterns when the cylinder makes one rotation). From FIGS. 5 and 6, the recording / reproducing apparatus of the present embodiment has an advantage that even if the bit rate of the input encoded data string increases, it can be dealt with by a simple method of increasing the rotation speed of the cylinder. .

In the above description, the cylinder speed is doubled, but when a coded data string having a second bit rate N2 (N2> N1) higher than the first bit rate N1 is input. , The cylinder speed is approximately N2 / N1
Obviously the same thing can be said if you double.

A fourth embodiment of the present invention will be described with reference to FIGS. 7 and 8. In FIG. 7, what is different from the encoded data string recording / reproducing apparatus according to claim 1 is that
That is, only one channel is used for recording / reproducing, and the tape feed control circuit 5 is configured to change the recording track pitch according to the bit rate of the input encoded data. When the bit rate of the input encoded data string is N (Mbps), the tape pattern recorded by the recording head 6 has a recording track pitch of Tw ₂ (μm) as shown in FIG. 8B. When the bit rate is 2 × N (Mbps), the recording track pitch becomes wide and becomes Tw ₁ (μm) as shown in FIG. 8A.
As shown in FIG. 8, by increasing the recording track pitch, the CNR of the reproduced signal is improved, and the deterioration of the reproduced signal due to the bending of the recording track is reduced, so that the recordable and reproducible bit rate is increased. That is, by increasing the recording track pitch as described above, there is an advantage that it is possible to cope with a high bit rate of the input encoded data sequence without increasing the number of recording / reproducing channels.

[0032]

As described above, according to the recording / reproducing apparatus for the encoded data string of the present invention, the recording / reproducing channels are changed by changing the number of recording / reproducing channels against the change of the bit rate of the input data. It is possible to respond without changing the operating frequency of (1) and without changing the rotation speed of the cylinder (in a constant state).

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a coded data string recording apparatus according to an embodiment of the present invention.

FIG. 2 is a cylinder configuration diagram of a recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 3 is a recording track pattern diagram of a recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 4 is a block diagram showing an outline of a recording / reproducing apparatus for encoded data strings according to another embodiment of the present invention.

FIG. 5 is a block diagram showing the outline of a recording / reproducing apparatus for encoded data strings according to another embodiment of the present invention.

FIG. 6 is a cylinder configuration diagram of a recording / reproducing apparatus according to another embodiment of the present invention.

FIG. 7 is a block diagram showing an outline of a recording / reproducing apparatus for an encoded data string according to another embodiment of the present invention.

FIG. 8 is a recording track pattern diagram of a recording / reproducing apparatus of another embodiment of the present invention.

[Explanation of symbols]

 1 Input Terminal 2 Input I / F Circuit 3 Recording Processing Circuit 1 4 Recording Processing Circuit 2 5 Tape Feed Control Circuit 6 First Recording Head 7 Second Recording Head 8 Magnetic Tape 9 First Reproducing Head 10th 2 playback head 11 playback processing circuit 1 12 playback processing circuit 2 13 output I / F circuit device 14 output terminal 15 cylinder 16 analog video signal input terminal 17 analog recording processing circuit 18 analog recording head 19 analog playback head 20 analog Reproduction processing circuit 21 Analog video signal output terminal 22 Input switching circuit 23 First switch 24 Second switch 25 Recording processing circuit 26 Reproduction processing circuit 27 Cylinder drive circuit

Front page continuation (72) Inventor Masaaki Kobayashi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. An input coded data string has a bit rate of N1 or N2 (N1 <N2) and has two channels of output. When the bit rate is N2, the input coded data string has two channels. Input I / F circuit which outputs the input encoded data string from only one channel when the bit rate is N1 and the output of the input I / F circuit. And a second recording processing circuit for converting the data into a signal suitable for recording and supplying the same to the recording head, the recording head for writing on the magnetic tape, and the magnetic tape feeding according to the bit rate of the input encoded data string. A tape feed control circuit for changing the magnetic field, a reproducing head for reading from the magnetic tape, first and second reproducing processing circuits for performing a predetermined reproducing process on a reproduced signal from the reproducing head, Output I / that has a channel input and outputs a 2-channel input signal when the bit rate of the reproduced encoded data is N2, and outputs a 1-channel input signal when the bit rate is N1. A recording / reproducing apparatus for an encoded data string, which comprises an F circuit and changes the feeding speed of the magnetic tape according to the bit rate of the input encoded data string and the number of channels used for recording and reproduction. 2. An analog video signal is recorded, comprising an analog video signal input / output terminal, an analog recording processing circuit and an analog reproduction processing circuit for performing processing suitable for recording and reproducing the analog video signal on a magnetic tape. 2. The coded data string recording / reproducing apparatus according to claim 1, wherein the cylinder rotational speed is not changed between the case and the case of recording the coded data string. 3. An input I / F circuit for detecting the bit rate of an input coded data string, wherein the bit rate of the input coded data string changes to N1 or N2 (N1 <N2), and an input I / F. A recording processing circuit, which is connected to the output of the circuit, converts an input coded data string into a signal suitable for recording and supplies the signal to a recording head, a recording head for writing to a magnetic tape, and a bit rate of the input coded data string. A tape feed control circuit that changes the magnetic tape feed according to the above, a cylinder drive circuit that changes the number of rotations of the cylinder, a read head that reads from the magnetic tape, and a playback that performs a predetermined playback process on the playback signal from the playback head. Processing circuit and output I / that outputs a signal having the same configuration as the input encoded data string
A recording / reproducing apparatus for an encoded data string, comprising an F circuit, and changing the feeding speed of the magnetic tape and the number of cylinder revolutions according to the bit rate of the input encoded data string. 4. An input I / F circuit for detecting the bit rate of an input encoded data string, the bit rate of the input encoded data string changing to N1 or N2 (N1 <N2), and an input I / F. A recording processing circuit, which is connected to the output of the circuit, converts an input coded data string into a signal suitable for recording and supplies the signal to a recording head, a recording head for writing to a magnetic tape, and a bit rate of the input coded data string. A tape feed control circuit for changing the magnetic tape feed according to the following, a reproducing head for reading from the magnetic tape, a reproducing processing circuit for performing a predetermined reproducing process on a reproduced signal from the reproducing head, and an input encoded data string And an output I / F circuit that outputs signals of the same configuration, wherein only the feeding speed of the magnetic tape is changed according to the bit rate of the input encoded data string. Column of the recording and reproducing apparatus.