WO1998050919A1

WO1998050919A1 - Method and device for recording and reproducing digital signal

Info

Publication number: WO1998050919A1
Application number: PCT/JP1998/001941
Authority: WO
Inventors: Shigekazu Morikawa
Original assignee: Sanyo Electric Co., Ltd.
Priority date: 1997-05-07
Filing date: 1998-04-27
Publication date: 1998-11-12
Also published as: JPH10308065A

Abstract

While a magnetic tape (10) is transported, the signal surface of the magnetic tape (10) is scanned to record time-compressed digital signals on the magnetic tape (10) or to reproduce time-compressed digital signals reproduced on the magnetic tape (10). The time-compressed digital video signals which are recorded are reproduced accurately by time-expanding them with a simple construction. A control circuit (7) controls the transport of the magnetic tape (10) while writing the compressed digital signals reproduced from the magnetic tape (10) into a memory (9). When the signals are written in the memory (9) to the extent of its limit capacity, the magnetic tape (10) is transported in the reverse direction by a certain distance, and then the tape (10) is temporarily stopped. By reading the compressed digital signals to produce a predetermined free capacity, the transport of the magnetic tape (10) is resumed. This process is repeated.

Description

Description Digital signal recording / reproduction method and thigh area

According to the present invention, a tape-like recording medium such as a digital video tape recorder is run in the longitudinal direction, and the signal surface of the self-view is recorded, and a digital signal whose time is increased is recorded on the recording medium. The present invention relates to a method and apparatus for reproducing a digital signal time-contracted from a bell. Background

With the recent development of digital information transmission technologies such as satellite broadcasting, cable TV, and Inuichi Net, multimedia information such as digital transit signals can be sent directly to households without the difficulty of cassette tapes. The service to deliver is feasible.

In such services, for example, digital »signals to be delivered to each home are transmitted in time, and at each home, helical scanning is performed on the received digital» signals as a time-compressed bit stream. Azimuth recording on a cassette tape by a digital video tape recorder of the system is Rikikawa Noh. At the time of signal reproduction, a cassette tape is reproduced, and the resulting digital excitation signal obtained is subjected to time expansion, demodulation, DZA conversion, etc., to generate an analog video signal, which is transmitted to a TV receiver. Supply and turn elephants.

Note that, for example, the fractal 赚: ^: (see Nikkei Byte March 1997, pp. 321 to 325) can be used as the digital デジタル time of the elephant signal. According to 2 o'clock The ability to compress video of about a minute to about 5 minutes and record it on a cassette tape is the ability. The following two methods can be used to reproduce a time-compressed digital video signal with time expansion.

That is,

1. Decrease the tape run i¾g during playback uniformly according to the power factor.

2. After running the tape on the same boat as the signal recording for one frame (for example, one track), repeat the intermittent feed operation to stop and stop, and reduce the tape running speed during playback as an average value. .

However, in the first method, since the head trace angle differs from that at the time of signal recording due to a decrease in tape running, the head trace angle is changed according to the tape running speed during reproduction. There is a problem that this requires a special mechanism.

In the above method 2, the tape must be run and stopped frequently at an extremely short pitch, and the running of the tape is not stable for a certain period immediately after the start of running after the stop. There is a risk that signal reproduction from the tape may not be performed accurately.

Accordingly, a first object of the present invention is to provide a digital signal recording and reproducing method and a digital signal recording / reproducing method which can reproduce a digital elephant signal whose time has elapsed by a simple configuration while extending the time.

A second object of the present invention is to provide a digital signal recording / reproducing method capable of accurately reproducing and reproducing a digital elephant signal which has been subjected to time JI by extending the time. . Disclosure of the invention The digital signal recording / reproducing method according to the present invention is characterized in that a time-contracted digital signal is recorded on a recording device while a tape-shaped recording difficulty is caused to travel in a longitudinal direction, passing a signal surface of a self-recording difficulty. Or, it is to reproduce the digital signal that has been time Ii from the terrible recording sea, write the digital signal that is reproduced from the recording difficulty to the memory, control the running of the recording difficulty, and the memory is set to ^ f When the data is written to the maximum capacity, the operation of stopping the recording is stopped, and the operation of restarting the operation of the recording medium is repeated when a predetermined free space is generated in the memory by reading the digital signal.

Specifically, at the time of signal reproduction, the same boat as at the time of signal recording is caused to run for recording. When the digital signal is a video signal, the memory has a capacity capable of storing at least several frames of video signals.

In the above-described recording and reproducing method and apparatus of the present invention, a digital signal whose recording time has been recorded is written by setting and executing the signal recording mode. Then, when the signal reproduction mode is set, the running of the recording fiber and the signal reproduction by Zhao are started, and the writing of the JIS digital signal obtained by this to the memory is started. Also, when a signal read request is issued from the subsequent circuit to the memory, a compressed digital signal is read from the memory, and the signal is supplied to the subsequent circuit and subjected to necessary processing such as time expansion, etc. For example, the indication is started. Here, since the reading of the signal from the memory is performed at a speed higher than the writing speed of the signal, the area of the memory where the signal has been written gradually increases.

Then, when the memory is written to the specified limit capacity, the running of the recording difficulty is paused. As a result, only the reading of the digital signal from the memory is continued, and the free space of the memory is gradually increased. Then, at the time when a predetermined free space is generated in the memory, the recording difficult running and the writing of the digital signal to the memory. Is opened.

By repeating the above operation, the digital signal recorded in response to the recording difficulty is sequentially output to the subsequent circuit at ¾¾¾ according to the rise rate, and the time is extended.

In the specific configuration of the recording / reproducing method and apparatus according to the present invention, when the memory is written up to a certain limit capacity, the plow is driven in a predetermined direction and then stopped.

As a result, a certain amount of overlap is recorded on the recording every time the direction of travel is changed in scanning during signal reproduction.

In this specific configuration, after the recording medium is stopped, immediately after the forward traveling is started, even if the traveling speed of the recording medium is unstable, the traveling in the forward direction is performed in the previous step. By the time the vehicle travels to the position where it stopped, that is, 舰 is safe during the overlapped section. The signal is reproduced.

FIG. 1 is a block diagram showing a configuration of a digital signal recording / reproducing apparatus and a receiving apparatus according to the present invention, FIG. 2 is a flowchart showing a control procedure in signal reproduction of the digital signal recording / reproducing apparatus, and FIG. This is a time chart for explaining the signal reproducing operation. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment in which the present invention is applied to a digital signal distribution system will be described in detail with reference to the drawings. A digital signal distribution system according to the present invention comprises a digital signal recording / reproducing device (1) and a receiving device (2) as shown in FIG. 1, and the receiving device (2) has a receiver (2) having a display. 3) is connected.

The digital elephant signal distributed from the distribution station and received by the receiving device (2) is sent to the digital signal recording / reproducing device (1) and recorded on the play tape (10). After that, the read digital video signal reproduced from the magnetic tape (10) is supplied to the receiving device (2), subjected to necessary processing such as time expansion, and output to the receiver (3). An indication is made.

The digital signal recording / reproducing device (1) has the same configuration as the digital VTR of the helical scan ^^; を the running sleep of the tape (10), the rotation of the ヘッド ^ head (4), etc. A well-known VTR mechanism (5), a head amplifier (6) for amplifying a recording signal and a raw signal by a magnetic head (4), a control circuit (7) for controlling the VTR mechanism (5), and control An input key (8) for giving various instructions to the circuit (7) and a memory (9) having a storage capacity for a plurality of frames and used for signal reproduction processing as described later are provided.

Here, the control circuit (7) and the memory (9) form a basic configuration of the present invention, and the operation thereof will be described below.

On the other hand, the receiving device (2) is configured to receive the distribution of the digital elephant signal timed by fractal rise ^: etc., and is transmitted using, for example, a satellite profile transmission wave. The receiving circuit (12) receives the rising digital signal and supplies it to the digital signal recording / reproducing device (1), and issues a signal read command R to the memory (9) of the digital signal recording / reproducing device (1) and Extends necessary processing such as time expansion, demodulation processing, DZA conversion, etc. to the digital signal D read in response to the thank-you order.It has a demodulation circuit (11). The analog elephant signal output from the long demodulation circuit (11) is output to the receiver (3). In the above digital elephant signal distribution system, when the signal recording mode is set by operating the input key (8), the VTR mechanism (5) is operated, and the viewing tape (10) is run and hidden at a constant rate. And the head (4) is turned feW]. The rising digital bell signal received by the receiving device (2) is supplied to the head (4) via the head amplifier (6) of the digital signal recording / reproducing device (1), and is fed to the tape (10). Azimuth recording is performed on the signal surface of the magnetic tape (10) by helical scanning by rotating the head (4). Here, the Ji digital video signal is a time signal that is about ² hours to about ⁵ minutes on the real time axis, i.e., TT, which is equivalent to about 5 minutes. It will be recorded over the length of the tape.

After that, when the signal playback mode is set by operating the input key (8), the VTR mechanism (5) is operated, and the テープ ^ tape (10) is run at the same time as the signal is recorded. At the same time, the head (4) is rotated at the same Jt as the signal recording. As a result, the digital transmission signal obtained from the play head (4) is written to the memory (9) via the head amplifier (6). At this time, the running of the observation tape (10) and the writing of the digital transmission signal to the memory (9) are controlled by the control circuit (7) with difficulty.

The digital difficult signal written in the memory (9) is sequentially read out in accordance with the signal read command R input from the expansion / demodulation circuit (11) of the receiving device (2), and the expansion / demodulation circuit (11) Supplied to

FIG. 2 shows a control procedure in a signal reproducing mode executed by the control circuit (7) of the digital signal recording / reproducing apparatus (1).

First, in step S1, it is determined whether or not a command to set the signal reproduction mode has been input. If the answer is yes, the signal reproduction mode is set in step S2. Next step In S3, it is determined whether or not the memory is in a "memory full" state in which the memory has been written to a certain limit capacity. If the determination is no, signal reproduction is continued. Also, in this process, when a signal read command is input from the receiving device (2), the digital signal »written in the memory is read.

Since the reading of the digital transport signal from the memory is performed at a low rate according to the duty ratio of the digital video signal, the writing of the digital elephant signal to the memory proceeds faster, and the writing of the memory (9) is performed. The embedded area will gradually expand.

Thereafter, when the determination is YES in step S3, the process proceeds to step S4, where the rewind reproduction for a plurality of frames is executed, and then the process is stopped in step S5. This will rewind the tape by a certain amount.

It should be noted that the recording signal obtained by rewinding reproduction is used only for tape rewinding control, and is not used for writing or indication to the memory. Therefore, only the reading of the digital signal ^ (elephant signal) from the memory is performed, and the writable area of the memory gradually expands.

Then, in step S6, it is determined whether or not the memory has reached a "memory empty" state in which a predetermined free space has been generated. Thereafter, if the result of the determination in step S6 is YES, the process returns to step S2, sets the reproduction mode, and continues to write the digital elephant signal to the memory.

According to the above control procedure, each time the memory becomes full, the tape is rewound by a certain amount, and reproduction of the river direction is started again from the rewind position. Each time, there will be a certain amount of overlap on the tape.

In this overlap section, since the tape has just started running, the running speed is unstable, and there is a possibility that an error may occur in signal reproduction. Since the boat is safe by the end of the procedure, in a new reproduction section following the overlap section, signal reproduction by stable running is performed.

Therefore, of the digital signals obtained by the two times in the overlap period, the signal obtained by the first Zhao is inverted, and the signal obtained by the second time is invalidated. An accurate reproduction signal can be obtained.

FIG. 3 shows a state in which the digital hidden signal recorded on the tape with the time jagged recorded therein is extended for a while and reproduced by the execution of the above control procedure.

The current video signal before the start time t 1 = 0 and the end time t 2 = T as shown in Fig. (A) is time-responsive at a predetermined rate, and is on the tape as shown in Fig. (B). It is recorded in the area ρ1 to ρ2.

First, as shown in FIG. 3 (c), the above-mentioned traveling control causes a step. In (1), the »signal is sequentially written to the memory as shown in (d) of the figure while the tape is running in the forward direction. As a result, the signal E1 is written to the memory of the first area A on the tape, and when the memory is full, the tape is rewound by a fixed amount in step (4) and stopped. Then, when the memory empty state is reached, the tape is again run in the forward direction at step <), and the I signal is sequentially written to the memory. As a result, the next video signal D2 in the area B on the tape is written to the memory, and when the memory is full, the tape is rewound by a fixed amount in step 、 and stopped. Thereafter, when the memory empty state is reached, the video signal is sequentially written to the memory while the tape is run in the forward direction again at step (1). As a result, the last video signal D3 in the area C on the tape is written to the memory.

In this way, the digital video signal of ~ ¾ recorded in each of the fiber areas A, B, and C on the tape is once written to memory, and then read out at a frequency corresponding to the fil rate. Being The time is extended according to the rate, and a reproduced signal with the start time t 1 = 0 and the end time t 2 = T is obtained as shown in FIG. 3 (e).

According to the digital signal distribution system according to the present invention as in ±, the digital signal recording / reproducing apparatus (1) only needs to set the same tape running in the signal recording mode in the signal reproduction mode. There is no need for a special key for matching, and a VTR mechanism with exactly the same configuration as before can be used.

In addition, since the memory has a storage capacity for a plurality of frames, the tape is rewound by a certain amount when stopping the tape, although the frequency of stopping the tape during signal reproduction is low. By providing an overlap section, errors during signal reproduction are avoided, so that high-quality reproduction can be obtained.

It should be noted that each fiber of the present invention is not limited to the above-described embodiment, and various deformations are T-functions within the feT surgical range described in the range of special FW requirements. For example, it is needless to say that the recording / reproduction text is not limited to the elephant signal, but may be an audio signal or other data signal. Industrial applicability

According to the digital signal recording / reproducing method and apparatus according to the present invention, for example, the same operation as that of the video precoder of の ^, that is, reproduction by forward tape feed, reverse tape feed, and thereafter Since the signal reproduction and the inter-decompression are performed by the rejection, a special mechanism is not required for the reproduction of the digital elephant signal that is kept on the time, and the configuration is simple.

Also, according to a specific configuration that gives an overlap over the record I », the time is digital! ^ In the reproduction of the elephant signal, the signal is reproduced by the stable running wisteria, so that the reproduced signal obtained is accurate and error-free.

Claims

The scope of the claims

1. While running the tape-shaped recording difficulty in the longitudinal direction, the signal surface of | ¾ | 3 recording difficulty is recorded, and the recorded digital signal is recorded in the recording difficulty, or the sickle is recorded in JI from the 3 recording difficulty. A digital signal recording and reproducing method that reproduces digital signals that have been recorded. In this case, the operation of restarting the running of the recording medium is repeated when a predetermined free space is generated in the memory by reading the request signal, when the running of the recording medium is stopped. Signal recording and playback method.

2. The digital signal recording / reproducing method according to claim 1, wherein when the memory is written up to a certain limit capacity, the recording sea is driven in a direction by a certain amount, and then stopped.

3. The digital signal recording / reproducing method according to claim 1 or 2, wherein the recording medium is run at the time of signal reproduction in the same manner as at the time of signal recording.

4. Tape running to make the signal surface of self-recording while running the tape-shaped recording in the longitudinal direction. · Zhao system, the signal recording system to record the digital signal after time ii in the recording dew, A signal reproduction system for reproducing a digital signal reproduced from a recording device, a memory for retrieving a digital signal reproduced from a recording thigh, and a control system for controlling running of recording »and signal writing to the memory. The control system writes the digital signal read from the signal surface of the recording difficulty to the memory while controlling the running of the recording difficulty, so that the memory has a certain limit capacity. When the data is written to the memory, the running of the recording medium is stopped, and the operation of restarting the running of the recording medium is repeated when a predetermined free space is generated in the memory by reading the digital signal. Digital signal Recording and reproducing apparatus.

5. The digital signal recording / reproducing device according to claim 4, wherein the control system causes the recording to run in a fixed amount when the data is written to the limited capacity of the memory, and then stops the recording.

6. The digital signal recording / reproducing apparatus according to claim 4 or claim 5, wherein the control system causes the same boat as the signal recorder to run the recording difficulty when reproducing the signal.