JP3151115B2 - Recording and playback 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 recording and reproducing apparatus for recording an input signal on a magnetic tape and reproducing a signal recorded on the magnetic tape.

[0002]

2. Description of the Related Art There is a recording / reproducing apparatus in which a video signal for one frame is divided into a plurality of tracks and recorded on a magnetic tape. This recording / reproducing apparatus is designed such that if the first track is written first after switching frames during recording, and if the first track is not read first during reproduction, the previous or next frame is included in the reproduced video. Is mixed, and normal playback cannot be performed.

For this reason, in this method, a means for always synchronizing the frame of a device for reproducing from the first track with respect to the switching of frames is required. As a conventional example, Japanese Patent Application Laid-Open No. 5-328274 discloses that the mechanical control unit does not operate in frame synchronization at the time of reproduction, performs tracking control in synchronization with a temporary frame switching signal, and temporarily performs tracking control based on the track number detected by the demodulation unit. A method of generating a reference pulse having a different phase in synchronization with the frame switching signal to synchronize the frame of the signal processing unit and reproducing a signal recorded on a magnetic tape has been proposed.

[0004]

However, in the conventional frame synchronization method, when the mode of the apparatus changes from a recording state to a reproduction state, the method of obtaining frame synchronization of the apparatus is different. Becomes discontinuous. As a result, when the video signal to be displayed on the monitor is switched from the recorded image to the reproduced image, there is a problem that the screen is greatly disturbed once.

[0005] In addition, different frame switching signals are synchronized between recording and reproduction, and during reproduction, a plurality of frame switching signals having different phases are mixed in the apparatus, and the frame switching signals synchronized with each circuit are different. For this reason, the number of wirings in the device increases, and the frame synchronization timing differs for each circuit, so that the mode setting of the circuit constituting the device becomes complicated.

Accordingly, it is an object of the present invention to provide a recording / reproducing apparatus capable of preventing screen disturbance.

[0007]

A recording / reproducing apparatus according to claim 1 receives a recording / reproducing switching signal, generates a frame switching signal synchronized with the input signal at the time of recording, and outputs the frame switching signal at the time of recording at the time of reproducing. Frame switching signal generating means for generating a frame switching signal of a continuous phase; recording means for recording an input signal on a magnetic tape in synchronization with the frame switching signal; and recording means for recording on a magnetic tape in synchronization with the frame switching signal. Reproduction means for reproducing the reproduced signal.

According to a second aspect of the present invention, there is provided a frame switching signal generating means for generating a frame switching signal synchronized with an input signal during recording, and generating a frame switching signal having a phase continuous with the frame switching signal during recording during reproduction. And operates in synchronization with the frame switching signal, records an input signal on a magnetic tape during recording, and operates in synchronization with the frame switching signal, and a signal processing unit that reproduces a signal recorded on the magnetic tape during reproduction. A frame switching signal generating means and a mode setting means for setting a mode of the signal processing means, wherein the frame switching signal generating means and the signal processing means synchronously change to the set mode in synchronization with the frame switching signal. It is a feature.

[0009]

According to the recording / reproducing apparatus of the first aspect, the frame switching signal generating means generates a frame switching signal synchronized with the input signal during recording, and records the input signal on the magnetic tape in synchronization with the frame switching signal. During reproduction, a frame switching signal having a phase continuous with the frame switching signal at the time of recording is generated by the frame switching signal generating means, and the signal recorded on the magnetic tape is reproduced in synchronization with the frame switching signal. When the mode of the device changes to the playback state, the frame switching signal for synchronizing the frame of the device has the same phase as that of the recording, so that the continuity of the synchronization signal of the output video signal is maintained, and therefore, the image is displayed on the monitor. When the video signal is switched from the recorded image to the reproduced image, it is possible to prevent the screen from being disturbed.

According to the recording / reproducing apparatus of the second aspect, in addition to the same operation as the first aspect, the number of wirings in the apparatus can be reduced by synchronizing the apparatus with one frame switching signal regardless of the mode. it can. Also, the mode setting of the blocks constituting the device is performed in synchronization with the frame switching signal, and the mode change timing of each block is performed by the frame switching signal. However, collision of signals can be avoided, and mode transition of the device can be easily performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. That is, in this embodiment, a digital recording / reproducing device is taken as an example of the magnetic recording / reproducing device, and particularly, frame synchronization will be described. FIG.
FIG. 1 shows a block diagram of a digital recording / reproducing apparatus. In addition,
In the recording / reproducing apparatus, in addition to the video signal, an audio signal, character information, copy guard information, and various other additional information are recorded. For simplicity, FIG. 1 shows a configuration in which only the video signal is processed. I have.

The digital recording / reproducing apparatus shown in FIG. 1 is a recording means for recording image data 1 as an input signal on a magnetic tape 11, and reproduces data recorded on the magnetic tape 11 to produce a video signal 19. It comprises a reproducing means 41 which is a reproducing system for outputting. The recording means 40 is an A / D
A conversion unit 2, a shuffle unit 4, a compression unit 5, an error correction code adding unit 6, a modulation unit 7, a recording signal generation unit 8, a recording head 10,
It comprises a frame switching signal generator 3 and a mechanical controller 9.

The frame switching signal generating means 3 receives the image data 1 and the recording / reproducing switching signal 20 as input, detects the head of the frame of the image data 1, and generates a frame switching signal synchronized with the input signal. FIG. 2 shows the internal configuration of the frame switching signal generating means 3. More specifically, the blocks and their operations will be described. A frame head detector 304 detects the head of the frame of the synchronization signal of the input image data 1 and outputs a high pulse. The output signal of the frame head detector 304 is a flip-flop 308,
An output signal sequentially input to 309 and edge detected is output to a first input of the selector 305. 301 is a clock signal. At the time of recording, the selector 3
05 is selected and the frame counter 306 is selected.
Are reset by the output signal of the selector 305, and the frame switching signal 307 synchronized with the image data 1 is output. At the time of reproduction, since the reset signal is not output from the selector 305 by the recording / reproduction switching signal 20, the frame counter 306 performs the counting operation continuously from the time of recording. As a result, during playback, the continuous frame switching signal 30
7 is output. Note that in FIG.
Reference numeral 04 denotes a configuration for detecting the head of the frame of the synchronization signal of the input image data 1.
It is also possible to adopt a configuration in which a frame pulse indicating the beginning of a frame is directly input without the 04.

The shuffle section 4, compression section 5, error correction code adding section 6, modulation section 7, and mechanical control section 9 receive a frame switching signal and operate as a reference for frame synchronization of each block. That is, the mechanical control unit 9 rotates the rotating drum in synchronization with the frame switching signal to adjust the tracking of the recording head 10. On the other hand, the image data 1 of the input signal is converted into digital data by the A / D conversion unit 2, rearranged by the shuffle unit 4, subjected to DCT conversion, quantization and variable length coding by the compression unit 5, and added with an error correction code. The error correction code is added by the unit 6, modulated by the modulation unit 7, and recorded on the magnetic tape 11 via the recording signal output unit 8 and the recording head 10.

The reproduction means 41 includes a D / A conversion section 18, a deshuffle section 17, an expansion section 16, an error correction section 15, and a demodulation section 1.
4, a reproduction signal generation unit 13, a reproduction head 12, a frame switching signal generation unit 3, and a mechanical control unit 9. The frame switching signal generating means 3 outputs the recording / reproducing switching signal 2
0 is input, and a frame switching signal having a phase continuous with the frame switching signal at the time of recording is generated. Deshuffle part 17,
The decompression unit 16, the error correction unit 15, the demodulation unit 14, and the mechanical control unit 9 receive a frame switching signal as input and operate as a reference for frame synchronization of each block. That is, the mechanical control unit 9 rotates the rotating drum in synchronization with the frame switching signal at the time of reproduction to adjust the tracking of the reproduction head 12.

The output signal of the reproducing head 12 for tracing the magnetic tape 11 is supplied to a demodulating unit 1 via a reproducing signal generating unit 13.
4, demodulated, error-corrected by an error correction unit 15, decompressed by a decompression unit 16,
The D / A converter 1
8 outputs a video signal. According to a first embodiment,
The frame switching signal generating means 3 generates a frame switching signal synchronized with the input signal at the time of recording, and records the input signal on the magnetic tape 11 in synchronization with the frame switching signal. When the mode of the apparatus changes from the recording to the reproduction state, the frame switching signal of the phase thus generated is generated by the frame switching signal generating means 3 and the signal recorded on the magnetic tape 11 is reproduced in synchronization with the frame switching signal. In addition, the continuity of the synchronization signal of the output video signal is maintained since the frame switching signal for synchronizing the frame of the apparatus has the same phase as that of the recording,
Therefore, when the video signal projected on the monitor is switched from the recorded image to the reproduced image, it is possible to prevent the screen from being disturbed.

A second embodiment of the present invention will be described with reference to FIG. That is, the digital recording / reproducing apparatus described in the first embodiment has a recording system and a reproducing system, but usually, the recording system and the reproducing system share a circuit. FIG.
Signal processing means 43 which shares recording and reproducing circuits
FIG. 1 is a block diagram of a digital recording / reproducing apparatus having the following.
The recording / reproducing apparatus records audio signals, character information, copy guard information, and other various types of additional information in addition to the video signal. For simplicity, FIG. 3 shows a configuration in which only the video signal is processed. Is shown.

In FIG. 3, the frame switching signal generating means 23 detects the head of the frame of the image data 21 as an input signal at the time of recording, generates a frame switching signal, and has a phase continuous with the frame switching signal at the time of recording at the time of reproduction. Generate a frame switching signal. The internal configuration of the frame switching signal generating means 23 is the same as that of FIG. 2 except that the signal of the mode setting means 36 is input instead of the recording / reproducing switching signal 20, and the description is omitted.

The rearranging section 24 of the signal processing means 43,
Compression / decompression section 25, error correction code processing section 26, modulation / demodulation section 2
7. The mechanical control unit 29 and the mode setting unit 36 receive the frame switching signal and operate as a reference for frame synchronization of each block. The mode setting section 36 serially sets the mode setting such as switching between recording and reproduction to the frame switching signal generating means 23, the rearranging section 24, the compression / decompression section 25, the error correction code processing section 26, the modulation / demodulation section 27, and the mechanical control section 29. Perform by communication. The mode setting means 36 sequentially sets the mode of each block in the frame in synchronization with the frame switching signal. Then, the timing at which the mode of each block actually changes is performed in synchronization with the frame switching signal.

In the recording mode, the mechanical control unit 29 rotates the rotary drum in synchronization with the frame switching signal to adjust the tracking of the recording head 30. The image data 21 of the input signal is converted into digital data by an A / D converter 22, rearranged by a rearranger 24,
T-conversion, quantization and variable-length coding, error correction code processing section 26 adds an error correction code, modulates with modulation / demodulation section 27, and records on magnetic tape 31 via recording signal output section 28 and recording head 30. Is done.

In the reproducing mode, the mechanical control unit 29 rotates the rotating drum in synchronization with the frame switching signal to adjust the tracking of the reproducing head 32. Magnetic tape 3
The output signal of the reproducing head 32 for tracing 1 is input to the modulation / demodulation unit 27 via the reproduction signal generation unit 33 and demodulated. The error correction code processing unit 26 corrects the error. Quantization and IDCT conversion are performed, rearranged by the rearrangement unit 24, and a video signal is output from the D / A conversion unit 34.

According to the second embodiment, in addition to the same operation and effect as the first embodiment, the number of wires in the device can be reduced by synchronizing the device with one frame switching signal regardless of the mode. Can be. Also, the mode setting of the blocks constituting the device is performed in synchronization with the frame switching signal, and the mode change timing of each block is performed by the frame switching signal. However, collision of signals can be avoided, and mode transition of the device can be easily performed.

In the above-described embodiment, the input image data is an analog signal, but the digital data may be input directly without passing through the A / D converter. The video signal of the reproduction output is output as an analog signal through the D / A converter, but may be output without passing through the D / A. The mode setting by the mode setting means 36 may be parallel communication instead of serial communication.

As described above, the present invention has been described using the above-described embodiments. However, the configuration of the present invention can be realized by various methods other than the above.

[0025]

According to the recording / reproducing apparatus of the first aspect, the frame switching signal generating means generates a frame switching signal synchronized with the input signal at the time of recording, and synchronizes the input signal with the magnetic tape in synchronization with the frame switching signal. In order to reproduce the signal recorded on the magnetic tape in synchronization with the frame switching signal, a frame switching signal having a phase continuous with the frame switching signal at the time of recording is generated by the frame switching signal generating means during reproduction. When the mode of the device changes from recording to playback, the frame switching signal for synchronizing the frame of the device has the same phase as that of the recording, so that the continuity of the synchronization signal of the output video signal is maintained. When the video signal to be projected on the
There is an effect that the screen can be prevented from being disturbed.

According to the recording / reproducing apparatus of the second aspect, in addition to the same effect as the first aspect, the number of wirings in the apparatus can be reduced by synchronizing the apparatus with one frame switching signal regardless of the mode. it can. Also, the mode setting of the blocks constituting the device is performed in synchronization with the frame switching signal, and the mode change timing of each block is performed by the frame switching signal. However, collision of signals can be avoided, and mode transition of the device can be easily performed.

[Brief description of the drawings]

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

FIG. 2 is a block diagram of an internal configuration of a frame switching signal generator.

FIG. 3 is a block diagram illustrating a configuration of a digital recording / reproducing apparatus according to a second embodiment.

[Explanation of symbols]

 1, 21 Image data as input signal 3, 23 Frame switching signal generating means 11 Magnetic tape 40 Recording means 41 Reproducing means 43 Signal processing means

Continuation of the front page (72) Inventor Masato Mitsuda 1006 Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-5-328274 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) H04N 5/91-5/956 G11B 20/10-20/12 H04N 5/782-5/783

Claims (2)

(57) [Claims] 1. A frame switch for inputting a recording / reproduction switching signal, generating a frame switching signal synchronized with the input signal during recording, and generating a frame switching signal having a phase continuous with the frame switching signal during recording during reproduction. Signal generating means, recording means for recording an input signal on a magnetic tape in synchronization with the frame switching signal, and reproducing means for reproducing a signal recorded on the magnetic tape in synchronization with the frame switching signal. Recording and reproducing device provided. 2. A frame switching signal generating means for generating a frame switching signal synchronized with an input signal during recording, and generating a frame switching signal having a phase continuous with the frame switching signal during recording during reproduction. Signal processing means for recording an input signal on a magnetic tape during recording, and reproducing a signal recorded on the magnetic tape during reproduction, and operating in synchronization with the frame switching signal, A signal generation unit and a mode setting unit for setting a mode of the signal processing unit, wherein the frame switching signal generation unit and the signal processing unit are:
A recording / reproducing apparatus which changes to a mode set at the same time in synchronization with the frame switching signal.