JPH0697786B2 - Playback device for recorded information including device control information - Google Patents

Description

The present invention relates to a recorded information reproducing apparatus, and more particularly to a recorded information reproducing apparatus including apparatus control information such as address information for information retrieval or control information for controlling a reproducing operation.

On a recording medium such as a video disc, in addition to video and audio information, recording information such as address information for facilitating retrieval of such information or control information for designating an operation mode for reproducing a still image of a specific portion. Device control information for controlling the operation of the reproducing device is recorded as digital information, for example, a so-called Phillips code.

On the other hand, since the dropout phenomenon in the reproduced signal is unavoidable, a dropout compensation device is added to compensate the reproduced signal. In the case of having such a dropout compensation function, if a dropout occurs in a section including device control information such as address information or control information, dropout compensation is performed and, for example, 1H (1
(Horizontal line) will be replaced with the previous signal. For this reason, the normal information is not derived as the device control information, and an error occurs in the information search or reproduction operation, which significantly reduces the reliability, which is not preferable. If a section (for example, a V blanking section) is detected and the detection sensitivity of the dropout compensation circuit is lowered during that period, or if the compensation operation is stopped, the device control information will not be replaced with the information 1H before, and information retrieval or the like will be performed. It is possible to improve reliability. If the same device control information is recorded in consecutive 2H-equivalent sections, it is preceded by consecutive 2H-equivalent sections.
The detection sensitivity of the dropout compensation circuit is reduced or the function is stopped in the section equivalent to 1H, and then continues
If the dropout compensation operation is controlled to return to the normal operation state in the 1H equivalent section, the preceding device control information is output as it is without compensation, and the subsequent device control information is based on the same preceding information. Since the compensation is performed, the accuracy of reading the device control information can be significantly improved. Based on such knowledge, when the same device control information is recorded in the 1H equivalent section immediately before the 1H equivalent section including the device control information, only the 1H equivalent section immediately before this 1H equivalent section of the dropout compensation circuit The recorded information reproducing apparatus including means for substantially stopping the dropout detection operation has already been proposed by the present applicant.

However, in the recording information reproducing apparatus as described above, since the dropout compensation operation is stopped and released regardless of the content of the obtained information, for example, the same information is provided in the continuous 2H equivalent section. When the information of the preceding 1H equivalent section is mistakenly read due to dropout, the dropout compensation operation is canceled in the subsequent 1H equivalent section and the subsequent 1H
There is a drawback in that it is difficult to prevent malfunction in the information search or reproduction operation because the information in the corresponding section is replaced with incorrect information.

Therefore, an object of the present invention is to provide a recorded information reproducing apparatus with a dropout compensation function, which can improve the reading accuracy of the apparatus control information and improve the reliability of information retrieval or the stability of the reproducing operation.

The recorded information reproducing apparatus according to the present invention exists behind the section corresponding to the first horizontal line depending on a part or all of the information included in the section corresponding to the predetermined first horizontal line in the section including the device control information. The configuration includes means for selectively deciding whether to activate or stop the compensating operation of the dropout compensating circuit in the predetermined second horizontal line equivalent section.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, a reproduced RF signal including device control information is demodulated by a demodulator 1 and applied to a switching circuit 2 for dropout compensation. Also, the reproduced RF signal is input to the 1H delay circuit 3 and delayed by 1H, and after demodulated by the demodulator 4,
It is input to the switching circuit 2 described above. Furthermore, when a dropout detection circuit 5 is provided and a dropout in the reproduction RF signal is detected, a predetermined detection signal is output from the detection circuit 5 and supplied to the control input terminal of the switching circuit 2 via the analog switch circuit 6. To be done. 1H delay circuit 3 by this detection signal
Is output to the output terminal of the switching circuit 2 as a line output.

The output of the switching circuit 2 becomes the video signal output as it is and is input to the control information separation circuit 7. The control information separation circuit 7 is configured to detect the control information insertion section from the sync separation output by a sync separation circuit (not shown) and separate and extract the control information signal included in the video signal. The control information signal output from the control information separation circuit 7 is supplied to the control information decoding circuit 8. In the control information decoding circuit 8, the control information signal is decoded and an address signal for information retrieval or a mode command signal for commanding a mode in the reproducing operation is output. The output of the control information decoding circuit 8 is supplied to the control circuit (not shown) of the reproducing apparatus and the continuous line signal detection circuit 9. The continuous line signal detection circuit 9 stores in advance, for example, information (content of the first byte of the program area in the case of a Phillips code) included in each 1H-equivalent section in the continuous 2H-equivalent section of the control information. The output of the storage means and the corresponding portion of the output of the control information decoding circuit 8 are compared, and when these two outputs match, a detection signal composed of a low level signal is output. The Philips code is, for example, a lead-in code of "88FFFF", which is inserted in two consecutive H line sections in the V blanking period.
There are some Philips codes inserted in one H line section. The output of the continuous line signal detection circuit 9 is supplied to one input terminal of a 2-input NAND (logical product) gate 10. At the other input terminal of the gate 10, for example, a control information insertion section is detected from a sync separation output by a sync separation circuit (not shown), and a control information section timing signal composed of a high level signal over this control information insertion section. The output of a control information section detection circuit (not shown) configured to output is supplied. The output of the gate 10 is supplied to the control input terminal of the analog switch circuit 6. When the two inputs of the gate 10 both become high level, that is, when the control information section timing signal is output and the continuous line signal detection signal is not output, the gate
The output of 10 becomes low level and the analog switch circuit 6 is turned off. Then, the supply of the dropout detection signal to the control input terminal of the switching circuit 2 is blocked, and the dropout compensation is stopped.

In the above configuration, the control information insertion section is detected from the horizontal synchronizing signal or the like as shown in FIG.
When the control information section timing signal is output as shown in FIG. 5, the output of the gate 10 becomes low level and the dropout compensation operation is stopped as shown in FIG. After that, as shown in FIG. 6B, the α-th and (α +
1) αH, (α +) starting from each of the horizontal synchronization signals
1) When the control information included in each H horizontal line equivalent section is information A which is, for example, address information,
If the control information A is previously stored in the storage means in the continuous line signal detection circuit 9, the vertical synchronization signal (α +
1) When the horizontal sync signal is generated, the continuous line detection signal is generated so that the output of the gate 10 becomes high level so that the stop of the dropout compensation operation is released at (α + 1) H. be able to.

Next, in the same manner as in FIGS. 2 (a) and 2 (d), the horizontal synchronizing signal and the control information section timing signal are shown in FIG. 3 (a),
The control information included in each section corresponding to one horizontal line of αH and (α + 1) H starting from the α-th and (α + 1) -th horizontal synchronizing signals from the vertical synchronizing signal is output as shown in (d). When the information B and C which mean different operation modes, for example, as shown in FIG. 7B, the continuous line signal detection signal is not output, so that the control information section timing signal exists as shown in FIG. During this period, the dropout compensation operation remains stopped.

Further, as in FIGS. 2 (a) and 2 (d), the horizontal synchronization signal and the control information section timing signal are shown in FIG. 4 (a),
Each of αH, (α + 1) H, and (α + 2) H that is output as shown in (d) and has α-th, (α + 1) -th, and (α + 2) -th horizontal synchronization signals as the start ends from the vertical synchronization signal.
The control information included in the section corresponding to the horizontal line is shown in FIG.
When the information D is D, D, and E as shown in FIG. 5, if the information D is stored in advance in the storage means in the continuous line signal detection circuit 9, the second information D is read out as shown in FIG. Therefore, the stop of the dropout compensation operation can be released at (α + 1) H.

The continuous line signal detection circuit 9 in FIG.
Although it has been stated that the continuous line signal detection signal is output in the section corresponding to the horizontal line, the continuous line signal detection circuit 9 controls the control information in the field immediately following the content of the information included in the control information section in each field divided by the vertical synchronization signal. It may be configured to output the continuous line signal detection signal in the section. For example, in each of the three consecutive fields, among the horizontal synchronizing signals as shown in FIG.
The control information contained in each 1 horizontal line equivalent section starting from the +1) th signal is A, A, B, C as shown in FIG.
And A, A respectively, and the combination of the information A, A indicates that the same information is not continuous in the next field,
The combination of information B and C shall indicate that the same information continues in the next field. In such a case, the continuous line signal detection circuit 9 compares the stored contents of the storage means in which the information B and C are stored in advance with the read information, and when these information match, the next field as shown in FIG. If it is constructed so as to output a continuous line signal detection signal of a low level over a period of time, an address section detection signal composed of a low level signal in the section (α + 1) H as shown in FIG. Signal (FIG. 6 (f)) with the output of an address section detection circuit (not shown) that generates a signal is used as one input of the gate 10, and the other input of the gate 10 becomes high level in the control information section. When the control information section timing signal ((g) in the figure) is supplied, the dropout compensation operation is controlled as shown in (e) in the figure.

As described in detail above, the recorded information reproducing apparatus according to the present invention removes the horizontal line equivalent section existing behind the horizontal line equivalent section containing this information according to the content of the read information, while performing the dropout compensation operation. Since the control information is not replaced with erroneous information, it is possible to improve the reading accuracy of the control information and prevent erroneous operation in information retrieval or reproduction operation. It will be possible. In particular, it exists after the section corresponding to one horizontal line in which this information was included, depending on the content of part of the read information, that is, the state of "1" or "0" of one bit in the plurality of read bits. If the stop of the dropout compensation operation in the section corresponding to one horizontal line is released, the effect obtained will be great.

In the above embodiment, according to the read information, one horizontal line corresponding section immediately after the one horizontal line corresponding section including the information and immediately after the field including the one horizontal line corresponding section including the information. Although the dropout compensation operation is controlled only in one of the control information sections in the field, it is also possible to perform the dropout compensation in both of these sections. Further, by doing so, it becomes possible to more accurately control the dropout compensation at the time of reproduction of, for example, a Phillips-MCA system video disc in which the address information and the control information are alternately included in each field. .

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIGS. 2 to 4 are timing charts for explaining the operation of the circuit of FIG. 1, and FIG. It is a figure which shows the timing chart for demonstrating operation | movement of the circuit of another Example. Explanation of code of main part 5 …… Dropout detection circuit 6 …… Analog switch 7 …… Control information separation circuit 8 …… Control information decoding circuit 9 …… Continuous line signal detection circuit 10 …… NAND gate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Soichi Iwamura, "Introduction to Video Discs and DAD" (Published by Corona Publishing on November 1, 1982) 128-131

Claims (3)

[Claims] 1. A dropout is detected by detecting a dropout in a reproduction signal of recorded video information including a control information signal for controlling an operation of a recording information reproducing apparatus for every section corresponding to at least two horizontal lines in a predetermined section. A recorded information reproducing apparatus having a dropout compensating circuit for compensation, comprising a section timing signal generating means for detecting the predetermined section of the reproduction signal and generating a section timing signal, and the control information signal from the reproduction signal. Extracting means (7, 8) for extracting a dropout compensation operation while the section timing signal is present, and the extraction control information signal supplied from the extracting means matches the control information signal stored in advance. When it is found that the dropout compensation operation is performed only in the section corresponding to the predetermined horizontal line thereafter (9, 10)
And a stored information reproducing apparatus including: 2. The recorded information reproducing apparatus according to claim 1, wherein the compensation operation control means performs a compensation operation control of dropout in a section corresponding to a predetermined horizontal line immediately after the coincidence determination. 3. A compensation operation control means for performing dropout compensation operation control of a section corresponding to a predetermined horizontal line in a field immediately after a field to which the coincidence determination is made. The recorded information reproducing apparatus according to the first item.