JP3139248B2 - 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 digital signal recording / reproducing apparatus for recording / reproducing a plurality of digital signals which are time-division multiplex-transmitted on the same transmission path such as CATV.

[0002]

2. Description of the Related Art In recent years, a digital VTR for recording and reproducing a signal on a recording medium with a digital signal instead of the conventional analog recording VTR has been actively developed. In this digital VTR, the information amount of a signal is much larger than that in the case of analog recording, so a wide band is required. However, in order to avoid this and compress the information amount, a discrete cosine transform (DCT) or an orthogonal transform is used. It is common practice to perform high-efficiency encoding and record it on a recording medium. Such digital VTRs include, for example, D1, D
2, D3 and D4 format VTRs are known.

[0003]

However, in such a conventional digital VTR, no consideration is given to recording and reproduction of a time-division multiplexed digital signal.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a digital signal recording / reproducing apparatus for recording / reproducing a time-division multiplexed digital signal.

[0005]

In order to solve the above-mentioned conventional problems, a digital signal recording / reproducing apparatus according to the present invention comprises a means for selecting a desired signal from a multiplexed input signal ; Recording speed for recording the recorded signal
Means for recording auxiliary information including recording speed information indicating the recording speed on the recording medium, and a reproduction signal determined from the reproduced signal during reproduction based on the recording speed information in the auxiliary information.
A means for reproducing a signal at a raw speed and selecting a desired signal is provided.

[0006]

The desired signal is selected from the input time-division multiplexed digital signal using the auxiliary information, and the selected signal is
The auxiliary information including the recording speed information indicating the recording speed for recording is recorded on the recording medium together with the selected signal, and at the time of reproduction , based on the recording speed information in the auxiliary information from the reproduced signal.
By reproducing a signal at the determined reproduction speed and selecting and outputting a desired signal from the reproduced signal, recording and reproduction of a time-division multiplexed digital signal can be easily performed.

[0007]

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

FIG. 1 is a block diagram schematically showing a digital VTR for recording a time division multiplex transmission digital signal according to a first embodiment of the present invention.

1, reference numeral 1 denotes a signal input terminal, 2 denotes a recording selection signal input terminal, 3 denotes a recording signal selection circuit, 4 denotes an error correction encoder, 5 denotes a recording head, 6 denotes a magnetic tape, and 7 denotes a reproducing head. , 8 is a control circuit, 9 is a reproduction signal selection circuit, 1
0 is an error correction decoder, 11 is a reproduction selection signal input terminal,
12 is a signal output terminal.

The time-division multiplexed video signal input from the signal input terminal 1 enters a recording signal selection circuit 3. Here, the auxiliary signal of the input signal includes transmission speed, recording time, recording time,
A signal representing information such as a program name. The signal may be originally provided in the input signal as a part of the input signal, or may be a part of a signal input from the recording selection signal input terminal 2 as user data. Is also good. A recording selection signal is input from the recording selection signal input terminal 2 to the recording signal selection circuit 3, and the recording signal is selected. For example, as shown in FIG. 2A, six video signals A, B, C, D, E, and F are time-division multiplexed and four of A, B, C, and D are selectively recorded. The output of the recording signal selection circuit 3 is as shown in FIG. The recording signal selection circuit 3 calculates the transmission speed of the output signal based on the transmission speed information in the auxiliary information of the signal to be selected, generates recording speed information corresponding to the transmission speed, and outputs it to the control circuit 8. At this time, the recording speed takes a minimum value that does not exceed the transmission speed of the output signal among a plurality of preset recording speeds. For example, in a digital VTR having a normal recording speed of 25 Mbps,
Recording speeds other than normal speed: 30 Mbps, 18 Mbps
s, 12 Mbps, 6 Mbps, and 3 Mbps are set, and the transmission rates before being multiplexed are 5 Mbps, 4 Mbps, 3 Mbps, and 6 Mbps, respectively.
s, 2Mbps, 10Mbps A, B, C, D, E,
A signal obtained by multiplexing the six signals of F
When recording two signals, the signals to be selected are A, B,
In the case of D and F, the transmission speed of the output signal of the recording signal selection circuit 3 is 25 Mbps, and the recording speed is a normal 25 Mbps.
s. When the signals A, B, D, and E are selected, the transmission speed of the output signal of the recording signal selection circuit 3 is 16
Mbps, and the recording speed is 18 Mbps, which is the minimum recording speed higher than 16 Mbps. When the recording speed is different from the normal recording speed based on the input recording speed information, the control circuit 8 causes the magnetic tape 6 to run at a speed different from that at the time of the normal reproduction, so that the recording signal selection circuit 3
To obtain the recording speed corresponding to the recording speed information output from. The signal selected by the recording signal selection circuit 3 is input to an error correction encoder 4 together with auxiliary information such as a recording speed, a recording time, a recording time, and a program name, and an error correction code is added. The output of the error correction encoder 4 is a recording head 5
And recorded on the magnetic tape 6.

When reproducing the signal recorded as described above, first, the reproduction head 7 assists the user in selecting the number of recording signals, recording speed, recording time, recording time, program name, etc. from the magnetic tape 6. The signal is reproduced. Reproduction signal selection circuit 9
Extracts recording speed information from the auxiliary signal and outputs it to the control circuit 8 as reproduction speed information. The control circuit 8 sets the running speed of the magnetic tape 6 to the speed at the time of signal recording based on the input reproduction speed information. Here, the reproducing head 7 is made to follow the recording track by making the traveling speed of the magnetic tape 6 equal to the traveling speed at the time of recording at the time of reproduction. It is. The reproduction signal selection circuit 9 selects one or more desired signals based on the auxiliary signal and the reproduction selection signal input from the reproduction selection signal input terminal 11, and outputs the selected signal to the error correction decoder 10. For example, the magnetic tape 6
If it is known that the recorded contents indicate that the four signals A, B, C, and D are multiplex-recorded, the input of the reproduction signal selection circuit 9 is as shown in FIG. 3A. When two signals A and C are selected and reproduced from the reproduced signal, the output of the reproduced signal selection circuit 9 is as shown in FIG. 3B. The output of the reproduction signal selection circuit 9 is input to an error correction decoder 10, which corrects an error of the input signal and outputs it from an output terminal 12.

If the cassette accommodating the magnetic tape is provided with a memory as an auxiliary storage medium, the auxiliary information is recorded in the memory so that the information is recorded on the magnetic tape prior to reproduction of the magnetic tape. An auxiliary signal of the signal can be obtained, and even if the auxiliary signal is lost due to an error at the time of reproduction, reading the auxiliary information from the memory is useful during reproduction.

As described above, according to the present invention, it is possible to select an arbitrary number of signals from a plurality of time-division multiplexed digital signals, record them simultaneously, and simultaneously reproduce an arbitrary number of signals from them. it can.

When a plurality of reproduction signals are selected and reproduced simultaneously, a plurality of reproduction signals are simultaneously output from separate output terminals at the same time, in addition to the case where the signals are output in a time-division multiplexed manner as described above. It is also conceivable to have a configuration for outputting the data.
The digital V according to the second embodiment of the present invention having such a configuration.
FIG. 4 is a block diagram schematically showing the TR.

In FIG. 4, 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11 are the same as those shown in FIG. 1, 21 is an output signal control circuit, 22, 23, 24, 25
Is an output circuit, and 26, 27, 28 and 29 are output terminals.

In the embodiment of FIG. 4, the operation of the recording system is the same as that of the embodiment of FIG. During playback,
A signal reproduced from the magnetic tape 6 by the reproducing head 7 is input to a reproduced signal selecting circuit 9. The reproduction signal selection circuit 9 has a reproduction selection signal input terminal 11 as in the embodiment of FIG.
Receives a reproduction selection signal. The reproduction signal selection circuit 9 extracts the recording speed information from the auxiliary signal in the reproduction signal as in the embodiment of FIG. 1, and outputs this to the control circuit 8 as the reproduction speed information. The control circuit 8 sets the running speed of the magnetic tape 6 to the speed at the time of signal recording based on the input reproduction speed information. Note that also in this example, non-tracking reproduction is possible. The reproduction signal selection circuit 9 selects one or more desired signals based on the auxiliary signal and the reproduction selection signal input from the reproduction selection signal input terminal 11, and outputs the selected signal to the error correction decoder 10.

In the example shown in FIG. 4, there are four simultaneous outputs, but of course, any number can be used. Also, the number of simultaneous output circuits and the number of playback signal selections are
They do not have to match. Here, for the sake of simplicity, a case where the number of selected reproduction signals is two will be described. A signal obtained by multiplexing two signals as shown in FIG. 3B is input to the error correction decoder 10. An auxiliary signal of the signal selected as the reproduction signal is input from the reproduction signal selection circuit 9 and output to the output signal control circuit 21.
In this case, the auxiliary signal is a selection number signal of “selection number = 2”, a signal representing the content of the selection signal of “first selection signal = A”, “second selection signal = C”, the transmission speed of each signal, and the like. is there. Based on the contents of these auxiliary signals, the output signal control circuit supplies clock pulses as output control signals to the respective output circuits 22, 23, 24 and 25. When two signals A and C are selected as in this example, the output control signal from the output signal control circuit 21 is sent to the output circuit 26 at the timing when the signal A is selected as shown in FIG. , And to the output circuit 27 at the timing indicating the signal C as shown in FIG. Each output circuit 2
2, 23, 24 and 25 are output signal control circuits 21 respectively.
Only the selected signal is processed and output in parallel from each output terminal 26, 27, 28, 29 at the transmission rate of each signal.

Next, the output circuits 26, 27, 28, 2 in FIG.
9 will be described in more detail with reference to FIG. FIG. 6 is a block diagram showing a configuration example of the output circuits 26, 27, 28 and 29 of FIG. In FIG. 6, 31 is an output control signal input terminal, 32 is an input terminal, 33 is an auxiliary signal input terminal,
34 is a memory control circuit, 35 is a memory, and 36 is an output terminal.

The signals A and C shown in FIG. 3b are time-division multiplexed and input to the input terminal of FIG. 5b, c, d, and e are connected to the output control signal input terminal 31.
Is input. The input output control signal is input to the memory control circuit 34, and the memory control circuit 34 writes only the signal selected by the output control signal to the memory 35. In this example, the output control signal is “Hig
The signal at the time of the "h" level is selected and written in the memory 35. Therefore, when the output control signal is as shown in FIG. 5B, the signal A in the input signal and the output control signal are shown in FIG. In such a case, the signal of C in the input signal is written to the memory 35. Further, the output control signal is shown in FIG.
If no input signal is selected as shown at e, the input signal is not written into the memory 35. on the other hand,
The memory control circuit 34 controls the reading from the memory 35 in parallel with the writing control to the memory 35 as described above. From the auxiliary signal input terminal 33 to the memory circuit 34,
An auxiliary signal of the signal selected by the reproduction signal selection circuit 9 is input. The input auxiliary signal includes the transmission rate information of the selected signal, so that in the case of the normal output transmission rate S0 and the transmission rate S of the selected signal,
By setting the transmission speed to S / S0 times the normal value, the signal is output at the original transmission speed.

As described above, in the present invention, an arbitrary number of signals can be recorded and reproduced from a plurality of multiplexed digital signals.

The case where the present invention is applied to a digital recording VTR has been described above, but application to a recording / reproducing apparatus other than the VTR is also possible.

The configuration of the embodiment used in the description is merely an example, and a similar effect can be obtained with an arbitrary configuration.

[0023]

As described above, according to the digital signal recording / reproducing apparatus of the present invention, multiplex recording / reproduction can be performed by using the auxiliary information of the multiplex signal. Can be used by time shifting. Also, for package media in which data is recorded in advance,
The present invention is effective.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention.

FIG. 2 is a signal configuration diagram for explaining the operation of the first embodiment of the present invention.

FIG. 3 is a signal configuration diagram for explaining the operation of the first embodiment of the present invention.

FIG. 4 is a block diagram of a second embodiment of the present invention.

FIG. 5 is a signal configuration diagram for explaining the operation of the second embodiment of the present invention.

FIG. 6 is a block diagram of an output circuit according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Signal input terminal 2 Recording selection signal input terminal 3 Recording signal selection circuit 4 Error correction encoder 5 Recording head 6 Magnetic tape 7 Reproduction head 8 Control circuit 9 Reproduction signal selection circuit 10 Error correction decoder 11 Reproduction selection signal input terminal Reference Signs List 12 signal output terminal 21 output signal control circuit 22, 23, 24, 25 output circuit 26, 27, 28, 29 output terminal 31 output control signal input terminal 32 input terminal 33 auxiliary signal input terminal 34 memory control circuit 35 memory 36 output terminal

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 20/10 H04N 5/92

Claims (2)

(57) [Claims] 1. One or more digital signals from an input signal
Input signal selecting means for selecting the input signal, and the input signal selecting means
Information about the output of the input signal and the output of the input signal selecting means
And recording means for recording the auxiliary information on a recording medium, wherein the auxiliary information includes an output of the input signal selecting means and the auxiliary information.
Recording speed for recording auxiliary information on the recording medium.
The recording means includes a signal indicating the transmission speed Ri of the input signal.
If the recording speed is not equal to the normal recording speed R, set it in advance.
Minimum recording speed equal to or higher than the Ri among a plurality of recording speeds determined
Digital signal recording and reproducing characterized by recording at a speed
Raw equipment. 2. One or more signals recorded on a recording medium
And when the one or more signals are recorded on the recording medium.
Play back auxiliary information including recording speed information indicating the recording speed
Digital signal recording / reproducing apparatus, comprising: a first reproducing means for reproducing the auxiliary information related to the signal.
And reproducing the signal based on the output of the first reproducing means.
Second reproducing means, and one or more desired signals from the output of the second reproducing means.
Selecting means for selecting a reproduction signal, wherein the second reproducing means selects the recording speed information in the auxiliary information.
The playback speed is determined from the information and the signal is played back.
Digital signal recording and reproducing device.