JPH0632464B2 - Recording information reproducing apparatus for PAL system color video information recording disk - Google Patents

Description

The present invention relates to a color signal processing device for reproducing color recorded information, and more particularly to reproducing information on a disc in which a color video signal based on the PAL (Phase Alternation Line) system is recorded for each frame for one frame. Disk information reproducing apparatus.

The color video signal Ep of the PAL system is Ep = Y + (B−Y) sinω st ± (R−Y) · cosω
st …… (1) Given to the formula. Where Y is the luminance signal, B and R
Indicates blue and red signals, and ωs is the angular frequency of the color subcarrier (subcarrier), which is about 4.43 MHz. The symbol ± in the equation (1) means phase inversion for each horizontal scanning line, and the RY components of the carrier color signal are subcos ± st having a phase difference of 180 ° for each horizontal scanning line. The carrier signal is AM-modulated and transmitted. Therefore, the color burst signal is transmitted by the R side on the receiver side.
It is necessary to also serve as information for inverting the phase of the Y component demodulation subcarrier for each line. Therefore, as shown in the vector diagram of FIG. 1, the color burst signal is BY
Each line is switched to a phase of ± 135 ° about the axis and is sent as a signal sin (ω st ± 135 °) in which the phase is inverted.

In order to perform correct color demodulation on the receiver side of such a PAL color video signal, the phase inversion state of the color burst signal is determined and the polarity of the subcarrier signal of the RY component is set to 1
It is necessary to always invert in a fixed direction at every horizontal scanning period. Therefore, a burst phase discriminator is provided to discriminate the phase inversion state of the color burst signal, and when the subcarrier signal inversion operation is reversed and (RY) is demodulated, the phase inversion circuit of the subcarrier is concerned. After that, the correct demodulation is performed.

However, if the response of the burst phase discriminator is made fast, an erroneous reset pulse is generated in response to the noise when the noise is superimposed on the input color video signal, which is not preferable. Therefore, it is general to set a certain time constant and generate a reset pulse only when erroneous demodulation is performed for a certain period of time so as to be strong against noise. As described above, the method of providing the time constant is effective when receiving a television broadcast wave, but a video disk on which color video information is recorded is reproduced using a VDP (video disk player), and this reproduction output is reproduced. The following drawbacks occur when inputting to the above-mentioned image receiver for use.

That is, in VDP, in addition to the normal playback mode,
Special playback modes such as still image playback, double speed playback, triple speed playback, and slow playback are possible. In such special playback mode, the information detection point of the pickup is always instantaneously controlled to jump from the current tracking track to another recording track. A jump action is required. FIG. 2 shows a locus of pickup information detection points in the still image reproduction mode, for example, the dotted line 1 is the locus, and 2 and 3 are part of the adjacent recording tracks. Further, each section in the track corresponds to one horizontal scanning section, and one frame (two fields) video signal is recorded per track on the recording disk of the CAV (constant angular velocity) system, and the number of lines of the video signal. As shown in the figure, each horizontal sync signal portion (which is a boundary portion of each section) is recorded on the same radial line of the disk in an aligned manner.
The inversion state of the PAL phase (which means the phase of the color burst signal and the signal of (RY) cosωst) in the horizontal scanning section is completely opposite as shown in the figure. Therefore, for example, in the still image reproduction mode, a track jump for one track is performed, and thus the PAL phase inversion state is reversed at each track jump, but as described above, the color burst phase discriminator (PAL phase discriminator) on the receiver side. The reaction of (1) is slow because it is late for several field periods due to the setting of the time constant, so that the color killer operates and a black and white image is produced or correct color demodulation is not performed. As described above, in the reproduction mode involving track jumps for odd number of tracks (hereinafter referred to as special reproduction mode), the PAL phase is lost, so the phase is corrected so as to maintain it, and the PAL phase is corrected in the receiver. A video signal must be provided.

Therefore, it is considered to use a circuit as shown in FIG. 3 in VDP. In the figure, the reproduced color video signal is represented by a delay unit 4 and a PA serving as carrier color signal phase correction means.
The two outputs A ₂ and B ₂ are input to the L phase corrector 5, respectively, and output as reproduction output via the second switch (switch) 6 and become receiver input. The PAL phase corrector 5 is a BPF 5 as an extracting means for separating the carrier color signal and the luminance signal.
1 and LPF 52, and the BPF 51 extracts only the carrier color signal frequency component. The extracted output of the BPF 51 is phase-inverted by the PAL phase inverter 7 including the multiplier 53 and the LPF 54 and having the subcarrier signal generator 8 and the multiplier 9 which will be described later and the one input B ₁ of the first switch 55. Become. Also, the output of BPF 51, that is, P
The input A ₁ of the AL phase inverter 7 is directly connected to the first switch 55.
The output selected by the switch 55 is added to the luminance signal from the LPF 52 in the adder 56. This addition output serves as the input B ₂ of the second switch 6 as a phase correction signal.

A subcarrier signal generator 8 is provided which extracts only a color burst component from the output of the BPF 51 and follows this average phase and generates a subcarrier signal cosωst of the same frequency. This output frequency is multiplied by a multiplier 9. Double
A signal of cos2ωst is obtained. This signal is the multiplier 53
Is multiplied by the extracted output from the BPF 51, and so-called heterodyne conversion is performed to perform PAL phase inversion. More specifically, the carrier color signal including the color burst signal is sin (ωst +
), The output of the multiplier 53 is cos2ωst · sin (ωst +) = 1/2 · {sin (3ωst +
φ) + sin (ωst −)} …… 2. Only the fundamental wave component is extracted by the BPF 54
The sin (ωst−) component is obtained. Here, since the BY component of the carrier color signal is = 0 (see FIG. 1), the output of the BPF 54 becomes sinωst and is not subjected to phase inversion. Similarly, since the RY component is = π / 2, BPF5
The output of 4 becomes sin (ωst−π / 2), and the input sin (ωst
+ Π / 2) undergoes phase inversion. Since the color burst signal is = ± 135 °, the input sin (ωst ±
135 °), the output of BPF54 is sin Will also undergo phase reversal, and thus PA
L phase inversion becomes possible. In addition, this PAL phase inverter 7
In addition to this heterodyne system, a well-known glass delay line system can also be used.

In such a configuration, the second switch 6 is used during normal reproduction.
Is controlled so that the signal A ₂ is selected and the PAL phase corrector 5 is bypassed, and the reproduced signal is directly transmitted as the output of the reproducing device without signal deterioration. The delay device 4 is for matching the delay amount in the PAL phase corrector 5, and there is no big problem even if it is not necessary. In a special mode such as still image reproduction, the switch 6 is controlled so as to select the signal B ₂ , and the first switch 55 is alternately switched every time a jump command signal is generated, so that either the signal A ₁ or the signal B ₁ is switched. It is selected for each jump. By doing so, the inversion property of the PAL phase is maintained constant even after the jump operation, and it is expediently sent to the receiver.

However, the second switch 6 is used for the PAL phase corrector 5
Since the input / output of is selected, if the PAL phase inversion property at the output of the switch 6 before and after the switching of the switch 6 is not maintained, the time constant of the PAL phase discriminator of the receiver is long. The color demodulation is disturbed over the frame period and the color killer causes black and white. In order to make this state easier to understand, the case of the still image reproduction mode will be described.

In the still image reproduction mode, as shown in FIG. 2, the line n + of the track 3 is responded to in response to the jump command.
The pickup information detection point jumps instantly from line 4 to line n + 5 of track 2 to repeat the still image reproduction, but the signal selection state of both switches 55 and 6 in this mode is shown in FIG. It becomes like this. Figure (a) is the second
Is a reproduction mode signal for controlling the switch 6, and transitions from the normal reproduction mode to the still image reproduction mode at time t ₁ . (b) is a jump command signal, which is a trigger signal of a flip-flop (not shown) that generates a control signal for the first switch 55. (c) shows the signal selection state of the second switch 6, (d) and (e) show the signal selection state of the first switch 55, and there are two types as shown in (d) and (e). The state can be considered.

Considering the PAL phase inversion state immediately before and after the first jump pulse generation time t ₂ in the two states of the switch 55, as is clear from FIGS. 2 and 4 (d) and (e). , (D), the output B of the PAL phase inverter 7
_{Since 1} is selected by the switch 55, there is no problem because the PAL phase maintains a constant inversion state. On the other hand, in the case of (e), the switch 55 controls the input A ₁ of the PAL phase inverter 7.
Is selected, the PAL phase inversion property around time t ₂ is reversed and the above-mentioned inconvenience occurs. Thus, in the case of (e), the PAL phase inversion property is reversed in the first jump, but in the second and subsequent jumps, the first switch 55 is switched for each jump, so the PAL phase inversion property is changed. Is kept. Therefore, the color demodulation of the receiver is disturbed over a few frames immediately after the first jump.

The same phenomenon occurs when the special reproduction mode is changed to the normal reproduction mode. FIG. 5 shows the operation state in such a case, and (a) to (e) correspond to (a) to (e) of FIG. 4, respectively. There are two possible selection states (d) and (e) of the first switch 55 at the instant t _{3 when} the mode is changed to the normal reproduction mode.
In the case of (d), since the PAL phase is not inverted by the switch 55, even if the switch 6 is switched to select the signal A ₂ , the inversion property of the PAL phase is not destroyed at any time t ₃ . However, in the case of (e), the inversion property of the PAL phase is reversed before and after the time t ₃ , and the same inconvenience as described above occurs.

It is an object of the present invention to provide a recorded information reproducing apparatus for a PAL system color video information recording disk which eliminates the color disorder of a color image at the time of shifting from the special reproduction mode to the normal reproduction mode.

A recording information reproducing apparatus for a PAL system color video information recording disk according to the present invention includes a PAL system color video signal including one component of a carrier color signal and a color burst signal whose phase is inverted every one horizontal scanning period, one frame per track. A recording information reproducing apparatus for a PAL system color video information recording disk, which reads a recorded signal of a recorded disk by a pickup to obtain a reproduction signal thereof and causes the pickup to make a track jump in response to a track jump command signal. Extraction means for extracting a carrier color signal component and a luminance signal component from the signal, and one phase of the carrier color signal and the color burst signal among the carrier color signal components in the extraction output of the extracting means are inverted and output. Phase inverter and before during special playback mode A first selector for alternately selecting and outputting the carrier color signal component and the output of the phase inverter in the extraction output of the extraction means each time the track jump command signal is generated, and the extraction output of the extraction means. A carrier color signal phase correction means having a luminance signal component and an adder for adding the output of the first selector, and using the added output of the adder as a phase correction signal; the reproduction signal and the phase A second selector for selecting the correction signal in accordance with the normal reproduction mode and the special reproduction mode respectively, and during the special reproduction mode period of the track jump command signal at the transition from the special reproduction mode to the normal reproduction mode. Track jump commanding means for forcibly generating the track jump command signal when the number of occurrences is odd.

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

FIG. 6 is a diagram of a switch control circuit according to an embodiment of the present invention, which is for controlling the switches 6 and 55 in the circuit of FIG. The reproduction mode signal (a) is used as a control signal for the second switch 6 and serves as a gate signal for the OR gate 11 via the inverter 10. Gate 1
The gated signal of 1 is the jump command input (b), and this gate output (c) is used as the trigger signal of the flip-flop 12 and as 1 input of the AND gate 13. The jump command input (b) referred to here is a signal that is issued, for example, at every predetermined timing during the vertical blanking period and serves as a basis for a jump command pulse described later. An inverted signal of the reproduction mode signal is used for the clear input of the flip-flop 12, and the output (d) of the flip-flop 12 becomes the trigger input of the MMV (monostable multivibrator) 14 and also the first switch 5
5 control signal. The output of this MMV14
(e) is one input of the OR gate 15, and the reproduction mode signal (a) is applied to the other inputs. The output (f) of the OR gate 15 is used as the other input of the AND gate 13, and the output (g) of the gate 13 becomes a jump command pulse. The jump command pulse (track jump command signal) is used to cause the pickup for reading the recorded information on the disk to jump the track according to the reproduction mode.

7 (a) to 7 (g) respectively show the waveforms of the signal (a) to (g) of each part of the circuit of FIG. 6, respectively, and show the control of the first and second switches 55 and 6. It is assumed that each switch selects the signal B ₁ or B ₂ when the signal is at the high level and selects the signal A ₁ or A ₂ when it is at the low level. Therefore, before and after the transition time t ₁ from the normal reproduction mode to the special reproduction mode, the second switch 6 outputs the output signal A ₂ to the output signal B _{2 of the} delay circuit 4 equivalent to the input signal of the PAL phase corrector 5.
Switch to. Special playback mode such as between still image playback mode _(t 1 _{~t 3)} jump command input at predetermined intervals to trigger the flip-flop 12 through the gate 11.

The flip-flop 12 that has been cleared until then is released from the reset state during the special reproduction mode, and is triggered by the first jump command signal Ca, and the Q output changes from the low level to the high level. Therefore, the first switch 55 is forcibly initialized to always select the signal B ₁ from the signal A _{1 with the first} jump command signal Ca as a boundary.
The output B ₁ of the L phase inverter 7 is derived and the PAL phase is inverted. Although the PAL phase between adjacent tracks is inverted by the initial setting means, the switch 55 immediately after the jump is always in the state of (d) in FIG. 4, so that the color disorder on the receiver side is eliminated.

Since the flip-flop 12 is inverted every time the jump command signal (c) is generated during this period, the switching state of the switch 55 is controlled for each jump command signal (c), and the correct PAL phase inversion property is maintained thereafter. During this time, at t _{1 to} t ₃ , the MMV 14 is triggered by the fall of the Q output (d) of the flip-flop 12 and outputs a low level single-shot pulse as shown in (e), while the gate 15 is in the high level reproduction mode. Since it is closed by the signal (a), this low level pulse (e) is not derived and the OR gate 15
Output (f) remains high.

Therefore, the gate 13 is opened and closed, and the jump command signal which is the output (c) of the gate 11 is output as it is as the jump command pulse (g) of the system.

Consider a case where the still image reproduction mode is changed to the normal reproduction mode at time t ₃ . In the one case, that is, when the flip-flop 12 is inverted by the jump command signal Cf immediately before the time t ₃ and its Q output transits to the low level as shown in FIG. 7D, the first switch 55 causes the PAL phase inverter 7 to operate. Input signal A ₁ is selected. Therefore, time t ₃
Even if the second switch 6 is switched to select the input signal A ₂ of the PAL phase corrector 5 at, the PAL phase inversion state before and after the time t ₃ is maintained constant.

On the other hand, in the other case, that is, the jump command signal Cf
By this, the flip-flop 12 is inverted and its Q output becomes high level, and the reproduction mode signal (a) which is a clear pulse is generated.
In case of transitioning to a low level at time t _{3 due} to (indicated by a dotted line in the figure), MMV14 is triggered by the fall of the Q output (d), and at time t ₃ is indicated by a dotted line in FIG. The low-level single-shot pulse shown is output. Since this passes through the gate 13 via the gate 15 in the open state, the time t1
From t1 to t3, a pulse similar to the jump command pulse generated based on the jump command input signal (b) is forcibly output. By such a track jump compulsory command means, the track jump operation of the pickup is forcibly performed by the one forcibly generated jump pulse. By doing this, the time t
Immediately before ₃ , the phase inversion output from the switch 55 is derived, and immediately after that, the recording signal of the track having a phase matching the phase inversion output is derived as a reproduction signal by the forced track jump operation. As a result, the PAL phase inversion property is maintained constant immediately before and after time t ₃ .

In other words, the Q output of the flip-flop 12 is at the high level at the end of the special reproduction mode, and the P output by the switch 55 is P.
This is a problem when the AL phase inversion output is derived, but the fact that the Q output of the flip-flop 12 is at a high level means that the jump command signal (b) causes the Q output of the flip-flop 12 to be cleared to a low level at the initial stage. This is a case where the special reproduction mode is ended by generating an odd number of triggers, and in this case, one jump command pulse is forcibly output as described above to maintain the continuity of PAL phase inversion. Is there. Therefore, it is easy to detect the odd number of times the jump command pulse is generated from the start point of the special reproduction mode by the flip-flop, but it is also possible to use a method using a counter or the like, and a computer means such as a microprocessor can be used to Even when the system is configured, the operation control can be performed similarly.

Also, depending on the timing of ending the special reproduction mode, etc., the switch is switched in a predetermined direction so that the PAL phase inversion output is selected at the time of transition to the next special reproduction mode, thereby preventing an adverse effect at the time of transition to the next special reproduction mode. It is also possible to do so.

In the above description, the case where the still image is reproduced as the special reproduction mode has been described as an example, but the same can be applied to other various modes.

As described above, according to the present invention, it is possible to reproduce a PAL system color video signal without causing any color disturbance even during reproduction in the special mode, and it is possible to obtain a reproducing apparatus having excellent characteristics.

[Brief description of drawings]

FIG. 1 is a vector diagram of a carrier color signal of the PAL system, FIG. 2 is a diagram showing a relationship between a track of a pickup information detection point and a recording track during reproduction in a special mode, and FIG. 3 is a color signal processing circuit of VDP. Block diagrams, FIGS. 4 and 5 are diagrams for explaining operation states of the circuit of FIG. 3, FIG. 6 is a circuit diagram of an embodiment of the present invention, and FIG. 7 is an operation waveform of each part of the circuit of FIG. It is a figure. Description of symbols of main parts 5 ... PAL phase corrector 6 ... second switch 7 ... PAL phase inverter 12 ... flip-flop 14 ... MMV 55 ... first switch 56 ... adder

Claims (1)

[Claims] 1. A recording signal of a disc in which a PAL system color video signal including one component of a carrier color signal whose phase is inverted every horizontal scanning period and a color burst signal is recorded by one frame per track is read by a pickup. A recording information reproducing apparatus for a PAL system color video information recording disk which obtains the reproduction signal and causes the pickup to perform a track jump in response to a track jump command signal, wherein a carrier color signal component and a luminance signal component are generated from the reproduction signal. Extracting means for extracting, a phase inverter for inverting and outputting the phase of one component of the carrier color signal and the color burst signal among the carrier color signal components in the extraction output of the extracting means, and during the special reproduction mode period Each time the track jump command signal is generated, the extraction output of the extraction means A first selector for alternately selecting and outputting the carrier color signal component and the output of the phase inverter, and a luminance signal component in the extraction output of the extracting means and the output of the first selector are added. And a carrier color signal phase correction means for using the addition output of the adder as a phase correction signal, and the reproduction signal and the phase correction signal are selected in accordance with the normal reproduction mode and the special reproduction mode, respectively. And a second selector which controls the track jump command signal when the number of occurrences of the track jump command signal during the special playback mode is odd during the transition from the special playback mode to the normal playback mode. And a recorded information reproducing apparatus for a PAL system color video information recording disk, which comprises: